服务网关zuul----zuul中的动态刷新路由配置

Spring Cloud实战小贴士：Zuul处理Cookie和重定向

所以解决该问题的思路也很简单，我们只需要通过设置sensitiveHeaders即可，设置方法分为两种：

全局设置：
- zuul.sensitive-headers=
指定路由设置：
- zuul.routes.<routeName>.sensitive-headers=
- zuul.routes.<routeName>.custom-sensitive-headers=true

重定向问题

在使用Spring Cloud Zuul对接Web网站的时候，处理完了会话控制问题之后。往往我们还会碰到如下图所示的问题，我们在浏览器中通过Zuul发起了登录请求，该请求会被路由到某WebSite服务，该服务在完成了登录处理之后，会进行重定向到某个主页或欢迎页面。此时，仔细的开发者会发现，在登录完成之后，我们浏览器中URL的HOST部分发生的改变，该地址变成了具体WebSite服务的地址了。这就是在这一节，我们将分析和解决的重定向问题！

出现该问题的根源是Spring Cloud Zuul没有正确的处理HTTP请求头信息中的Host导致。在Brixton版本中，Spring Cloud Zuul的PreDecorationFilter过滤器实现时完全没有考虑这一问题，它更多的定位于REST API的网关。所以如果要在Brixton版本中增加这一特性就相对较为复杂，不过好在Camden版本之后，Spring Cloud Netflix 1.2.x版本的Zuul增强了该功能，我们只需要通过配置属性zuul.add-host-header=true就能让原本有问题的重定向操作得到正确的处理。关于更多Host头信息的处理，读者可以参考本文之前的分析思路，可以通过查看PreDecorationFilter过滤器的源码来详细更多实现细节。

http://blog.didispace.com/spring-cloud-zuul-cookie-redirect/

Spring cloud使用/refresh端点手动刷新配置

一介绍
很多场景下，需要在运行期间动态调整配置。如果配置发生了修改，微服务也应该实现配置的刷新。
下面实现配置的手动刷新。
二新建项目microservice-config-client-refresh
三为项目添加spring-boot-starter-actuator依赖，该依赖包含了/refresh端点，用于配置的刷新。
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
</dependencies>
四在Controller上添加注解@RefreshScope。添加@RefreshScope的类会在配置更改时得到特殊处理。
package com.itmuch.cloud.study.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RefreshScope
public class ConfigClientController {
@Value("${profile}")
private String profile;
@GetMapping("/profile")
public String hello() {
return this.profile;
}
}
五测试
1 启动microservice-config-server
2 启动microservice-config-client-refresh
3 访问http://localhost:8081/profile,获得结果
dev-1.0
4 修改Git仓库中microservice-foo-dev.properties的文件内容为：
profile=dev-1.0-change
5 重新访问http://localhost:8081/profile,获得结果依然是：
dev-1.0
6 发送post请求到http://localhost:8081/refresh,结果返回
[
"config.client.version",
"profile"
]
7 再次访问http://localhost:8081/profile，返回结果为：
dev-1.0-change
说明配置已经刷新
---------------------
作者：chengqiuming
来源：CSDN
原文：https://blog.csdn.net/chengqiuming/article/details/80872615
版权声明：本文为博主原创文章，转载请附上博文链接！

https://tech.asimio.net/2017/10/10/Routing-requests-and-dynamically-refreshing-routes-using-Spring-Cloud-Zuul-Server.html

https://www.cnblogs.com/flying607/p/8459397.html

《spring扩展点之三：Spring 的监听事件 ApplicationListener 和 ApplicationEvent 用法，在spring启动后做些事情》

《服务网关zuul之七：zuul中的动态刷新路由配置》

《ApplicationEvent事件机制源码分析》

在spring-cloud-netflix-core-1.4.4.RELEASE.jar中org.springframework.cloud.netflix.zuul.RoutesRefreshedEvent.java

@SuppressWarnings("serial")
public class RoutesRefreshedEvent extends ApplicationEvent {
private RouteLocator locator;

public RoutesRefreshedEvent(RouteLocator locator) {
    super(locator);
    this.locator = locator;
}

public RouteLocator getLocator() {
    return this.locator;
}

}

在spring-cloud-netflix-core-1.4.4.RELEASE-sources.jar中的org.springframework.cloud.netflix.zuul.zuulZuulServerAutoConfiguration.java配置了监听事件。

    private static class ZuulRefreshListener
            implements ApplicationListener<ApplicationEvent> {
    @Autowired
    private ZuulHandlerMapping zuulHandlerMapping;

    private HeartbeatMonitor heartbeatMonitor = new HeartbeatMonitor();

    @Override
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof ContextRefreshedEvent
                || event instanceof RefreshScopeRefreshedEvent
                || event instanceof RoutesRefreshedEvent) {
            this.zuulHandlerMapping.setDirty(true);
        }
        else if (event instanceof HeartbeatEvent) {
            if (this.heartbeatMonitor.update(((HeartbeatEvent) event).getValue())) {
                this.zuulHandlerMapping.setDirty(true);
            }
        }
    }

}</pre>

关于spring的ApplicationEvent见《spring扩展点之三：Spring 的监听事件 ApplicationListener 和 ApplicationEvent 用法，在spring启动后做些事情》

https://blog.csdn.net/weixin_34267123/article/details/86021770

java配置

@Configuration
public class ZuulConfig {
<span class="hljs-meta"><span class="hljs-meta">@Bean</span>(name=<span class="hljs-string"><span class="hljs-string">"zuul.CONFIGURATION_PROPERTIES"</span>)
<span class="hljs-meta"><span class="hljs-meta">@RefreshScope</span>
<span class="hljs-meta"><span class="hljs-meta">@ConfigurationProperties</span>(<span class="hljs-string"><span class="hljs-string">"zuul"</span>)
<span class="hljs-meta"><span class="hljs-meta">@Primary</span>
<span class="hljs-function"><span class="hljs-keyword"><span class="hljs-function"><span class="hljs-keyword">public</span> ZuulProperties </span><span class="hljs-title"><span class="hljs-function"><span class="hljs-title">zuulProperties</span></span><span class="hljs-params"><span class="hljs-function"><span class="hljs-params">()</span> </span>{
    <span class="hljs-keyword"><span class="hljs-keyword">return</span> <span class="hljs-keyword"><span class="hljs-keyword">new</span> ZuulProperties();
}

}

修改路由

到git config server，修改zuul的路由，比如

zuul:
  host:
    socket-timeout-millis: 60000
    connect-timeout-millis: 30000
  proxy:
    addProxyHeaders: true
  routes:
    baidu:
      path: /baidu
      url: http://baidu.com

刷新

curl -i -X POST localhost:10000/refresh

验证

curl -i localhost:10000/routes

作者：go4it
链接：https://www.jianshu.com/p/a9332b111002
來源：简书
简书著作权归作者所有，任何形式的转载都请联系作者获得授权并注明出处。

深入理解SpringCloud之配置刷新

阅读目录

　　我们知道在SpringCloud中，当配置变更时，我们通过访问http://xxxx/refresh，可以在不启动服务的情况下获取最新的配置，那么它是如何做到的呢，当我们更改数据库配置并刷新后，如何能获取最新的数据源对象呢？下面我们看SpringCloud如何做到的。

回到顶部

一、环境变化

1.1、关于ContextRefresher

　　当我们访问/refresh时，会被RefreshEndpoint类所处理。我们来看源代码：

/*
 * Copyright 2013-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.cloud.endpoint;
import java.util.Arrays;

import java.util.Collection;

import java.util.Set;
import org.springframework.boot.actuate.endpoint.AbstractEndpoint;

import org.springframework.boot.context.properties.ConfigurationProperties;

import org.springframework.cloud.context.refresh.ContextRefresher;

import org.springframework.jmx.export.annotation.ManagedOperation;

import org.springframework.jmx.export.annotation.ManagedResource;
/**


@author Dave Syer


@author Venil Noronha

*/

@ConfigurationProperties(prefix = "endpoints.refresh", ignoreUnknownFields = false)

@ManagedResource

public class RefreshEndpoint extends AbstractEndpoint<Collection<String>> {
private ContextRefresher contextRefresher;
public RefreshEndpoint(ContextRefresher contextRefresher) {

super("refresh");

this.contextRefresher = contextRefresher;

}
@ManagedOperation

public String[] refresh() {

Set<String> keys = contextRefresher.refresh();

return keys.toArray(new String[keys.size()]);

}
@Override

public Collection<String> invoke() {

return Arrays.asList(refresh());

}


}

　　通过源代码我们了解到：当访问refresh端点时，实际上执行的是ContextRefresher的refresh方法，那么我们继续追踪源代码，找到其refresh方法：

public synchronized Set<String> refresh() {
        Map<String, Object> before = extract(
                this.context.getEnvironment().getPropertySources());
        addConfigFilesToEnvironment();
        Set<String> keys = changes(before,
                extract(this.context.getEnvironment().getPropertySources())).keySet();
        this.context.publishEvent(new EnvironmentChangeEvent(context, keys));
        this.scope.refreshAll();
        return keys;
    }

　　我们可以看到refresh方法做了如下几件事情：

　　1）获取刷新之前的所有PropertySource

　　2) 调用addConfigFilesToEnvironment方法获取最新的配置

　　3) 调用changes方法更新配置信息

　　4) 发布EnvironmentChangeEnvent事件

　　5）调用refreshScope的refreshAll方法刷新范围

　　我们重点关注一下2，3，4步骤

1.2、addConfigFilesToEnvironment方法

　　我们先来看看这个方法是怎么实现的：

/* for testing */ ConfigurableApplicationContext addConfigFilesToEnvironment() {
        ConfigurableApplicationContext capture = null;
        try {
            StandardEnvironment environment = copyEnvironment(
                    this.context.getEnvironment());
            SpringApplicationBuilder builder = new SpringApplicationBuilder(Empty.class)
                    .bannerMode(Mode.OFF).web(false).environment(environment);
            // Just the listeners that affect the environment (e.g. excluding logging
            // listener because it has side effects)
            builder.application()
                    .setListeners(Arrays.asList(new BootstrapApplicationListener(),
                            new ConfigFileApplicationListener()));
            capture = builder.run();
            if (environment.getPropertySources().contains(REFRESH_ARGS_PROPERTY_SOURCE)) {
                environment.getPropertySources().remove(REFRESH_ARGS_PROPERTY_SOURCE);
            }
            MutablePropertySources target = this.context.getEnvironment()
                    .getPropertySources();
            String targetName = null;
            for (PropertySource<?> source : environment.getPropertySources()) {
                String name = source.getName();
                if (target.contains(name)) {
                    targetName = name;
                }
                if (!this.standardSources.contains(name)) {
                    if (target.contains(name)) {
                        target.replace(name, source);
                    }
                    else {
                        if (targetName != null) {
                            target.addAfter(targetName, source);
                        }
                        else {
                            // targetName was null so we are at the start of the list
                            target.addFirst(source);
                            targetName = name;
                        }
                    }
                }
            }
        }
        finally {
            ConfigurableApplicationContext closeable = capture;
            while (closeable != null) {
                try {
                    closeable.close();
                }
                catch (Exception e) {
                    // Ignore;
                }
                if (closeable.getParent() instanceof ConfigurableApplicationContext) {
                    closeable = (ConfigurableApplicationContext) closeable.getParent();
                }
                else {
                    break;
                }
            }
        }
        return capture;
    }

　　1) 该方法首先拷贝当前的Environment

　　2) 通过SpringApplicationBuilder构建了一个简单的SpringBoot启动程序并启动

builder.application().setListeners(Arrays.asList(new BootstrapApplicationListener(),
                            new ConfigFileApplicationListener()));

　　这里面会添加两个监听器分别为：BootstrapApplicationListener与ConfigFileApplicationListener，通过先前的学习，我们知道BootstrapApplicationListener是引导程序的核心监听器，而ConfigFileApplicationListener也是非常重要的类：

/*
 * Copyright 2012-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.boot.context.config;
import java.io.IOException;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.Collections;

import java.util.Iterator;

import java.util.LinkedHashSet;

import java.util.LinkedList;

import java.util.List;

import java.util.Queue;

import java.util.Set;
import org.apache.commons.logging.Log;
import org.springframework.beans.BeansException;

import org.springframework.beans.CachedIntrospectionResults;

import org.springframework.beans.factory.config.BeanFactoryPostProcessor;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.bind.PropertiesConfigurationFactory;

import org.springframework.boot.bind.PropertySourcesPropertyValues;

import org.springframework.boot.bind.RelaxedDataBinder;

import org.springframework.boot.bind.RelaxedPropertyResolver;

import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;

import org.springframework.boot.context.event.ApplicationPreparedEvent;

import org.springframework.boot.env.EnumerableCompositePropertySource;

import org.springframework.boot.env.EnvironmentPostProcessor;

import org.springframework.boot.env.PropertySourcesLoader;

import org.springframework.boot.logging.DeferredLog;

import org.springframework.context.ApplicationEvent;

import org.springframework.context.ConfigurableApplicationContext;

import org.springframework.context.annotation.ConfigurationClassPostProcessor;

import org.springframework.context.event.SmartApplicationListener;

import org.springframework.core.Ordered;

import org.springframework.core.annotation.AnnotationAwareOrderComparator;

import org.springframework.core.convert.ConversionService;

import org.springframework.core.convert.support.DefaultConversionService;

import org.springframework.core.env.ConfigurableEnvironment;

import org.springframework.core.env.EnumerablePropertySource;

import org.springframework.core.env.MutablePropertySources;

import org.springframework.core.env.PropertySource;

import org.springframework.core.env.PropertySources;

import org.springframework.core.io.DefaultResourceLoader;

import org.springframework.core.io.Resource;

import org.springframework.core.io.ResourceLoader;

import org.springframework.core.io.support.SpringFactoriesLoader;

import org.springframework.util.Assert;

import org.springframework.util.ResourceUtils;

import org.springframework.util.StringUtils;

import org.springframework.validation.BindException;
/**


{@link EnvironmentPostProcessor} that configures the context environment by loading


properties from well known file locations. By default properties will be loaded from


'application.properties' and/or 'application.yml' files in the following locations:


<ul>


<li>classpath:</li>


<li>file:./</li>


<li>classpath:config/</li>


<li>file:./config/:</li>


</ul>


<p>


Alternative search locations and names can be specified using


{@link #setSearchLocations(String)} and {@link #setSearchNames(String)}.


<p>


Additional files will also be loaded based on active profiles. For example if a 'web'


profile is active 'application-web.properties' and 'application-web.yml' will be


considered.


<p>


The 'spring.config.name' property can be used to specify an alternative name to load


and the 'spring.config.location' property can be used to specify alternative search


locations or specific files.


<p>


Configuration properties are also bound to the {@link SpringApplication}. This makes it


possible to set {@link SpringApplication} properties dynamically, like the sources


("spring.main.sources" - a CSV list) the flag to indicate a web environment


("spring.main.web_environment=true") or the flag to switch off the banner


("spring.main.show_banner=false").



@author Dave Syer


@author Phillip Webb


@author Stephane Nicoll


@author Andy Wilkinson


@author Eddú Meléndez

*/

public class ConfigFileApplicationListener

implements EnvironmentPostProcessor, SmartApplicationListener, Ordered {
private static final String DEFAULT_PROPERTIES = "defaultProperties";
// Note the order is from least to most specific (last one wins)

private static final String DEFAULT_SEARCH_LOCATIONS = "classpath:/,classpath:/config/,file:./,file:./config/";
private static final String DEFAULT_NAMES = "application";
/**

The "active profiles" property name.

*/

public static final String ACTIVE_PROFILES_PROPERTY = "spring.profiles.active";

/**

The "includes profiles" property name.

*/

public static final String INCLUDE_PROFILES_PROPERTY = "spring.profiles.include";

/**

The "config name" property name.

*/

public static final String CONFIG_NAME_PROPERTY = "spring.config.name";

/**

The "config location" property name.

*/

public static final String CONFIG_LOCATION_PROPERTY = "spring.config.location";

/**

The default order for the processor.

*/

public static final int DEFAULT_ORDER = Ordered.HIGHEST_PRECEDENCE + 10;

/**

Name of the application configuration {@link PropertySource}.

*/

public static final String APPLICATION_CONFIGURATION_PROPERTY_SOURCE_NAME = "applicationConfigurationProperties";

private final DeferredLog logger = new DeferredLog();
private String searchLocations;
private String names;
private int order = DEFAULT_ORDER;
private final ConversionService conversionService = new DefaultConversionService();
@Override

public boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {

return ApplicationEnvironmentPreparedEvent.class.isAssignableFrom(eventType)

|| ApplicationPreparedEvent.class.isAssignableFrom(eventType);

}
@Override

public boolean supportsSourceType(Class<?> aClass) {

return true;

}
@Override

public void onApplicationEvent(ApplicationEvent event) {

if (event instanceof ApplicationEnvironmentPreparedEvent) {

onApplicationEnvironmentPreparedEvent(

(ApplicationEnvironmentPreparedEvent) event);

}

if (event instanceof ApplicationPreparedEvent) {

onApplicationPreparedEvent(event);

}

}
private void onApplicationEnvironmentPreparedEvent(

ApplicationEnvironmentPreparedEvent event) {

List<EnvironmentPostProcessor> postProcessors = loadPostProcessors();

postProcessors.add(this);

AnnotationAwareOrderComparator.sort(postProcessors);

for (EnvironmentPostProcessor postProcessor : postProcessors) {

postProcessor.postProcessEnvironment(event.getEnvironment(),

event.getSpringApplication());

}

}
List<EnvironmentPostProcessor> loadPostProcessors() {

return SpringFactoriesLoader.loadFactories(EnvironmentPostProcessor.class,

getClass().getClassLoader());

}
@Override

public void postProcessEnvironment(ConfigurableEnvironment environment,

SpringApplication application) {

addPropertySources(environment, application.getResourceLoader());

configureIgnoreBeanInfo(environment);

bindToSpringApplication(environment, application);

}
private void configureIgnoreBeanInfo(ConfigurableEnvironment environment) {

if (System.getProperty(

CachedIntrospectionResults.IGNORE_BEANINFO_PROPERTY_NAME) == null) {

RelaxedPropertyResolver resolver = new RelaxedPropertyResolver(environment,

"spring.beaninfo.");

Boolean ignore = resolver.getProperty("ignore", Boolean.class, Boolean.TRUE);

System.setProperty(CachedIntrospectionResults.IGNORE_BEANINFO_PROPERTY_NAME,

ignore.toString());

}

}
private void onApplicationPreparedEvent(ApplicationEvent event) {

this.logger.replayTo(ConfigFileApplicationListener.class);

addPostProcessors(((ApplicationPreparedEvent) event).getApplicationContext());

}
/**

Add config file property sources to the specified environment.
@param environment the environment to add source to
@param resourceLoader the resource loader
@see #addPostProcessors(ConfigurableApplicationContext)

*/

protected void addPropertySources(ConfigurableEnvironment environment,

ResourceLoader resourceLoader) {

RandomValuePropertySource.addToEnvironment(environment);

new Loader(environment, resourceLoader).load();

}

/**

Bind the environment to the {@link SpringApplication}.
@param environment the environment to bind
@param application the application to bind to

*/

protected void bindToSpringApplication(ConfigurableEnvironment environment,

SpringApplication application) {

PropertiesConfigurationFactory<SpringApplication> binder = new PropertiesConfigurationFactory<SpringApplication>(

application);

binder.setTargetName("spring.main");

binder.setConversionService(this.conversionService);

binder.setPropertySources(environment.getPropertySources());

try {

binder.bindPropertiesToTarget();

}

catch (BindException ex) {

throw new IllegalStateException("Cannot bind to SpringApplication", ex);

}

}

/**

Add appropriate post-processors to post-configure the property-sources.
@param context the context to configure

*/

protected void addPostProcessors(ConfigurableApplicationContext context) {

context.addBeanFactoryPostProcessor(

new PropertySourceOrderingPostProcessor(context));

}

public void setOrder(int order) {

this.order = order;

}
@Override

public int getOrder() {

return this.order;

}
/**

Set the search locations that will be considered as a comma-separated list. Each
search location should be a directory path (ending in "/") and it will be prefixed
by the file names constructed from {@link #setSearchNames(String) search names} and
profiles (if any) plus file extensions supported by the properties loaders.
Locations are considered in the order specified, with later items taking precedence
(like a map merge).
@param locations the search locations

*/

public void setSearchLocations(String locations) {

Assert.hasLength(locations, "Locations must not be empty");

this.searchLocations = locations;

}

/**

Sets the names of the files that should be loaded (excluding file extension) as a
comma-separated list.
@param names the names to load

*/

public void setSearchNames(String names) {

Assert.hasLength(names, "Names must not be empty");

this.names = names;

}

/**


{@link BeanFactoryPostProcessor} to re-order our property sources below any


{@code @PropertySource} items added by the {@link ConfigurationClassPostProcessor}.

*/

private class PropertySourceOrderingPostProcessor

implements BeanFactoryPostProcessor, Ordered {
private ConfigurableApplicationContext context;
PropertySourceOrderingPostProcessor(ConfigurableApplicationContext context) {

this.context = context;

}
@Override

public int getOrder() {

return Ordered.HIGHEST_PRECEDENCE;

}
@Override

public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)

throws BeansException {

reorderSources(this.context.getEnvironment());

}
private void reorderSources(ConfigurableEnvironment environment) {

ConfigurationPropertySources

.finishAndRelocate(environment.getPropertySources());

PropertySource<?> defaultProperties = environment.getPropertySources()

.remove(DEFAULT_PROPERTIES);

if (defaultProperties != null) {

environment.getPropertySources().addLast(defaultProperties);

}

}


}
/**


Loads candidate property sources and configures the active profiles.

*/

private class Loader {
private final Log logger = ConfigFileApplicationListener.this.logger;
private final ConfigurableEnvironment environment;
private final ResourceLoader resourceLoader;
private PropertySourcesLoader propertiesLoader;
private Queue<Profile> profiles;
private List<Profile> processedProfiles;
private boolean activatedProfiles;
Loader(ConfigurableEnvironment environment, ResourceLoader resourceLoader) {

this.environment = environment;

this.resourceLoader = resourceLoader == null ? new DefaultResourceLoader()

: resourceLoader;

}
public void load() {

this.propertiesLoader = new PropertySourcesLoader();

this.activatedProfiles = false;

this.profiles = Collections.asLifoQueue(new LinkedList<Profile>());

this.processedProfiles = new LinkedList<Profile>();
 // Pre-existing active profiles set via Environment.setActiveProfiles()
 // are additional profiles and config files are allowed to add more if
 // they want to, so don't call addActiveProfiles() here.
 Set&lt;Profile&gt; initialActiveProfiles = initializeActiveProfiles();
 this.profiles.addAll(getUnprocessedActiveProfiles(initialActiveProfiles));
 if (this.profiles.isEmpty()) {
     for (String defaultProfileName : this.environment.getDefaultProfiles()) {
         Profile defaultProfile = new Profile(defaultProfileName, true);
         if (!this.profiles.contains(defaultProfile)) {
             this.profiles.add(defaultProfile);
         }
     }
 }

 // The default profile for these purposes is represented as null. We add it
 // last so that it is first out of the queue (active profiles will then
 // override any settings in the defaults when the list is reversed later).
 this.profiles.add(null);

 while (!this.profiles.isEmpty()) {
     Profile profile = this.profiles.poll();
     for (String location : getSearchLocations()) {
         if (!location.endsWith("/")) {
             // location is a filename already, so don't search for more
             // filenames
             load(location, null, profile);
         }
         else {
             for (String name : getSearchNames()) {
                 load(location, name, profile);
             }
         }
     }
     this.processedProfiles.add(profile);
 }

 addConfigurationProperties(this.propertiesLoader.getPropertySources());

}
private Set<Profile> initializeActiveProfiles() {

if (!this.environment.containsProperty(ACTIVE_PROFILES_PROPERTY)

&& !this.environment.containsProperty(INCLUDE_PROFILES_PROPERTY)) {

return Collections.emptySet();

}

// Any pre-existing active profiles set via property sources (e.g. System

// properties) take precedence over those added in config files.

SpringProfiles springProfiles = bindSpringProfiles(

this.environment.getPropertySources());

Set<Profile> activeProfiles = new LinkedHashSet<Profile>(

springProfiles.getActiveProfiles());

activeProfiles.addAll(springProfiles.getIncludeProfiles());

maybeActivateProfiles(activeProfiles);

return activeProfiles;

}
/**

Return the active profiles that have not been processed yet. If a profile is
enabled via both {@link #ACTIVE_PROFILES_PROPERTY} and
{@link ConfigurableEnvironment#addActiveProfile(String)} it needs to be
filtered so that the {@link #ACTIVE_PROFILES_PROPERTY} value takes precedence.
<p>
Concretely, if the "cloud" profile is enabled via the environment, it will take
less precedence that any profile set via the {@link #ACTIVE_PROFILES_PROPERTY}.
@param initialActiveProfiles the profiles that have been enabled via

@return the unprocessed active profiles from the environment to enable

*/

private List<Profile> getUnprocessedActiveProfiles(

Set<Profile> initialActiveProfiles) {

List<Profile> unprocessedActiveProfiles = new ArrayList<Profile>();

for (String profileName : this.environment.getActiveProfiles()) {

Profile profile = new Profile(profileName);

if (!initialActiveProfiles.contains(profile)) {

unprocessedActiveProfiles.add(profile);

}

}

// Reverse them so the order is the same as from getProfilesForValue()

// (last one wins when properties are eventually resolved)

Collections.reverse(unprocessedActiveProfiles);

return unprocessedActiveProfiles;

}

private void load(String location, String name, Profile profile) {

String group = "profile=" + (profile == null ? "" : profile);

if (!StringUtils.hasText(name)) {

// Try to load directly from the location

loadIntoGroup(group, location, profile);

}

else {

// Search for a file with the given name

for (String ext : this.propertiesLoader.getAllFileExtensions()) {

if (profile != null) {

// Try the profile-specific file

loadIntoGroup(group, location + name + "-" + profile + "." + ext,

null);

for (Profile processedProfile : this.processedProfiles) {

if (processedProfile != null) {

loadIntoGroup(group, location + name + "-"

+ processedProfile + "." + ext, profile);

}

}

// Sometimes people put "spring.profiles: dev" in

// application-dev.yml (gh-340). Arguably we should try and error

// out on that, but we can be kind and load it anyway.

loadIntoGroup(group, location + name + "-" + profile + "." + ext,

profile);

}

// Also try the profile-specific section (if any) of the normal file

loadIntoGroup(group, location + name + "." + ext, profile);

}

}

}
private PropertySource<?> loadIntoGroup(String identifier, String location,

Profile profile) {

try {

return doLoadIntoGroup(identifier, location, profile);

}

catch (Exception ex) {

throw new IllegalStateException(

"Failed to load property source from location '" + location + "'",

ex);

}

}
private PropertySource<?> doLoadIntoGroup(String identifier, String location,

Profile profile) throws IOException {

Resource resource = this.resourceLoader.getResource(location);

PropertySource<?> propertySource = null;

StringBuilder msg = new StringBuilder();

if (resource != null && resource.exists()) {

String name = "applicationConfig: [" + location + "]";

String group = "applicationConfig: [" + identifier + "]";

propertySource = this.propertiesLoader.load(resource, group, name,

(profile == null ? null : profile.getName()));

if (propertySource != null) {

msg.append("Loaded ");

handleProfileProperties(propertySource);

}

else {

msg.append("Skipped (empty) ");

}

}

else {

msg.append("Skipped ");

}

msg.append("config file ");

msg.append(getResourceDescription(location, resource));

if (profile != null) {

msg.append(" for profile ").append(profile);

}

if (resource == null || !resource.exists()) {

msg.append(" resource not found");

this.logger.trace(msg);

}

else {

this.logger.debug(msg);

}

return propertySource;

}
private String getResourceDescription(String location, Resource resource) {

String resourceDescription = "'" + location + "'";

if (resource != null) {

try {

resourceDescription = String.format("'%s' (%s)",

resource.getURI().toASCIIString(), location);

}

catch (IOException ex) {

// Use the location as the description

}

}

return resourceDescription;

}
private void handleProfileProperties(PropertySource<?> propertySource) {

SpringProfiles springProfiles = bindSpringProfiles(propertySource);

maybeActivateProfiles(springProfiles.getActiveProfiles());

addProfiles(springProfiles.getIncludeProfiles());

}
private SpringProfiles bindSpringProfiles(PropertySource<?> propertySource) {

MutablePropertySources propertySources = new MutablePropertySources();

propertySources.addFirst(propertySource);

return bindSpringProfiles(propertySources);

}
private SpringProfiles bindSpringProfiles(PropertySources propertySources) {

SpringProfiles springProfiles = new SpringProfiles();

RelaxedDataBinder dataBinder = new RelaxedDataBinder(springProfiles,

"spring.profiles");

dataBinder.bind(new PropertySourcesPropertyValues(propertySources, false));

springProfiles.setActive(resolvePlaceholders(springProfiles.getActive()));

springProfiles.setInclude(resolvePlaceholders(springProfiles.getInclude()));

return springProfiles;

}
private List<String> resolvePlaceholders(List<String> values) {

List<String> resolved = new ArrayList<String>();

for (String value : values) {

resolved.add(this.environment.resolvePlaceholders(value));

}

return resolved;

}
private void maybeActivateProfiles(Set<Profile> profiles) {

if (this.activatedProfiles) {

if (!profiles.isEmpty()) {

this.logger.debug("Profiles already activated, '" + profiles

+ "' will not be applied");

}

return;

}

if (!profiles.isEmpty()) {

addProfiles(profiles);

this.logger.debug("Activated profiles "

+ StringUtils.collectionToCommaDelimitedString(profiles));

this.activatedProfiles = true;

removeUnprocessedDefaultProfiles();

}

}
private void removeUnprocessedDefaultProfiles() {

for (Iterator<Profile> iterator = this.profiles.iterator(); iterator

.hasNext()😉 {

if (iterator.next().isDefaultProfile()) {

iterator.remove();

}

}

}
private void addProfiles(Set<Profile> profiles) {

for (Profile profile : profiles) {

this.profiles.add(profile);

if (!environmentHasActiveProfile(profile.getName())) {

// If it's already accepted we assume the order was set

// intentionally

prependProfile(this.environment, profile);

}

}

}
private boolean environmentHasActiveProfile(String profile) {

for (String activeProfile : this.environment.getActiveProfiles()) {

if (activeProfile.equals(profile)) {

return true;

}

}

return false;

}
private void prependProfile(ConfigurableEnvironment environment,

Profile profile) {

Set<String> profiles = new LinkedHashSet<String>();

environment.getActiveProfiles(); // ensure they are initialized

// But this one should go first (last wins in a property key clash)

profiles.add(profile.getName());

profiles.addAll(Arrays.asList(environment.getActiveProfiles()));

environment.setActiveProfiles(profiles.toArray(new String[profiles.size()]));

}
private Set<String> getSearchLocations() {

Set<String> locations = new LinkedHashSet<String>();

// User-configured settings take precedence, so we do them first

if (this.environment.containsProperty(CONFIG_LOCATION_PROPERTY)) {

for (String path : asResolvedSet(

this.environment.getProperty(CONFIG_LOCATION_PROPERTY), null)) {

if (!path.contains("$")) {

path = StringUtils.cleanPath(path);

if (!ResourceUtils.isUrl(path)) {

path = ResourceUtils.FILE_URL_PREFIX + path;

}

}

locations.add(path);

}

}

locations.addAll(

asResolvedSet(ConfigFileApplicationListener.this.searchLocations,

DEFAULT_SEARCH_LOCATIONS));

return locations;

}
private Set<String> getSearchNames() {

if (this.environment.containsProperty(CONFIG_NAME_PROPERTY)) {

return asResolvedSet(this.environment.getProperty(CONFIG_NAME_PROPERTY),

null);

}

return asResolvedSet(ConfigFileApplicationListener.this.names, DEFAULT_NAMES);

}
private Set<String> asResolvedSet(String value, String fallback) {

List<String> list = Arrays.asList(StringUtils.trimArrayElements(

StringUtils.commaDelimitedListToStringArray(value != null

? this.environment.resolvePlaceholders(value) : fallback)));

Collections.reverse(list);

return new LinkedHashSet<String>(list);

}
private void addConfigurationProperties(MutablePropertySources sources) {

List<PropertySource<?>> reorderedSources = new ArrayList<PropertySource<?>>();

for (PropertySource<?> item : sources) {

reorderedSources.add(item);

}

addConfigurationProperties(

new ConfigurationPropertySources(reorderedSources));

}
private void addConfigurationProperties(

ConfigurationPropertySources configurationSources) {

MutablePropertySources existingSources = this.environment

.getPropertySources();

if (existingSources.contains(DEFAULT_PROPERTIES)) {

existingSources.addBefore(DEFAULT_PROPERTIES, configurationSources);

}

else {

existingSources.addLast(configurationSources);

}

}


}
private static class Profile {
 private final String name;

 private final boolean defaultProfile;

 Profile(String name) {
     this(name, false);
 }

 Profile(String name, boolean defaultProfile) {
     Assert.notNull(name, "Name must not be null");
     this.name = name;
     this.defaultProfile = defaultProfile;
 }

 public String getName() {
     return this.name;
 }

 public boolean isDefaultProfile() {
     return this.defaultProfile;
 }

 @Override
 public String toString() {
     return this.name;
 }

 @Override
 public int hashCode() {
     return this.name.hashCode();
 }

 @Override
 public boolean equals(Object obj) {
     if (obj == this) {
         return true;
     }
     if (obj == null || obj.getClass() != getClass()) {
         return false;
     }
     return ((Profile) obj).name.equals(this.name);
 }

}
/**


Holds the configuration {@link PropertySource}s as they are loaded can relocate


them once configuration classes have been processed.

*/

static class ConfigurationPropertySources

extends EnumerablePropertySource<Collection<PropertySource<?>>> {
private final Collection<PropertySource<?>> sources;
private final String[] names;
ConfigurationPropertySources(Collection<PropertySource<?>> sources) {

super(APPLICATION_CONFIGURATION_PROPERTY_SOURCE_NAME, sources);

this.sources = sources;

List<String> names = new ArrayList<String>();

for (PropertySource<?> source : sources) {

if (source instanceof EnumerablePropertySource) {

names.addAll(Arrays.asList(

((EnumerablePropertySource<?>) source).getPropertyNames()));

}

}

this.names = names.toArray(new String[names.size()]);

}
@Override

public Object getProperty(String name) {

for (PropertySource<?> propertySource : this.sources) {

Object value = propertySource.getProperty(name);

if (value != null) {

return value;

}

}

return null;

}
public static void finishAndRelocate(MutablePropertySources propertySources) {

String name = APPLICATION_CONFIGURATION_PROPERTY_SOURCE_NAME;

ConfigurationPropertySources removed = (ConfigurationPropertySources) propertySources

.get(name);

if (removed != null) {

for (PropertySource<?> propertySource : removed.sources) {

if (propertySource instanceof EnumerableCompositePropertySource) {

EnumerableCompositePropertySource composite = (EnumerableCompositePropertySource) propertySource;

for (PropertySource<?> nested : composite.getSource()) {

propertySources.addAfter(name, nested);

name = nested.getName();

}

}

else {

propertySources.addAfter(name, propertySource);

}

}

propertySources.remove(APPLICATION_CONFIGURATION_PROPERTY_SOURCE_NAME);

}

}
@Override

public String[] getPropertyNames() {

return this.names;

}


}
/**


Holder for {@code spring.profiles} properties.

*/

static final class SpringProfiles {
private List<String> active = new ArrayList<String>();
private List<String> include = new ArrayList<String>();
public List<String> getActive() {

return this.active;

}
public void setActive(List<String> active) {

this.active = active;

}
public List<String> getInclude() {

return this.include;

}
public void setInclude(List<String> include) {

this.include = include;

}
Set<Profile> getActiveProfiles() {

return asProfileSet(this.active);

}
Set<Profile> getIncludeProfiles() {

return asProfileSet(this.include);

}
private Set<Profile> asProfileSet(List<String> profileNames) {

List<Profile> profiles = new ArrayList<Profile>();

for (String profileName : profileNames) {

profiles.add(new Profile(profileName));

}

Collections.reverse(profiles);

return new LinkedHashSet<Profile>(profiles);

}


}


}

　　根据javadoc注释的说明，这个类会从指定的位置加载application.properties或者application.yml并将它们的属性读到Envrionment当中，其中这几个方法大家关注下：

    @Override
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof ApplicationEnvironmentPreparedEvent) {
            onApplicationEnvironmentPreparedEvent(
                    (ApplicationEnvironmentPreparedEvent) event);
        }
        if (event instanceof ApplicationPreparedEvent) {
            onApplicationPreparedEvent(event);
        }
    }

　　当springboot程序启动时一定会触发该事件监听，如果当前是 ApplicationEnvironmentPreparedEvent事件就会调用 onApplicationEnvironmentPreparedEvent方法，最终该方法会执行：

    @Override
    public void postProcessEnvironment(ConfigurableEnvironment environment,
            SpringApplication application) {
        addPropertySources(environment, application.getResourceLoader());
        configureIgnoreBeanInfo(environment);
        bindToSpringApplication(environment, application);
    }

　其中 bindToSpringApplication方法为：

/**
     * Bind the environment to the {@link SpringApplication}.
     * @param environment the environment to bind
     * @param application the application to bind to
     */
    protected void bindToSpringApplication(ConfigurableEnvironment environment,
            SpringApplication application) {
        PropertiesConfigurationFactory<SpringApplication> binder = new PropertiesConfigurationFactory<SpringApplication>(
                application);
        binder.setTargetName("spring.main");
        binder.setConversionService(this.conversionService);
        binder.setPropertySources(environment.getPropertySources());
        try {
            binder.bindPropertiesToTarget();
        }
        catch (BindException ex) {
            throw new IllegalStateException("Cannot bind to SpringApplication", ex);
        }
    }

　　很明显该方法是将Environment绑定到对应SpringApplication上，通过这个类就可以获取到我们更改过后的配置了

1.3、changes方法

private Map<String, Object> changes(Map<String, Object> before,
            Map<String, Object> after) {
        Map<String, Object> result = new HashMap<String, Object>();
        for (String key : before.keySet()) {
            if (!after.containsKey(key)) {
                result.put(key, null);
            }
            else if (!equal(before.get(key), after.get(key))) {
                result.put(key, after.get(key));
            }
        }
        for (String key : after.keySet()) {
            if (!before.containsKey(key)) {
                result.put(key, after.get(key));
            }
        }
        return result;
    }

　　changes方法其实就是处理配置变更信息的，分以下几种情况：

　　1）如果刷新过后配置文件新增配置就添加到Map里

　　2) 如果有配置变更就添加变更后的配置

　　3) 如果删除了原先的配置，就把原先的key对应的值设置为null

　　至此经过changes方法后，上下文环境已经拥有最新的配置了。

1.4、发布事件

　　当上述步骤都执行完毕后，紧接着会发布EnvrionmentChangeEvent事件，可是这个事件谁来监听呢？在这里我贴出官网的一段描述：

　　　应用程序将收听EnvironmentChangeEvent，并以几种标准方式进行更改（用户可以以常规方式添加ApplicationListeners附加ApplicationListeners）。当观察到EnvironmentChangeEvent时，它将有一个已更改的键值列表，应用程序将使用以下内容：

1.重新绑定上下文中的任何@ConfigurationProperties bean

2.为logging.level.*中的任何属性设置记录器级别

　　根据官网描述我们知道将变更一下操作行为@ConfigurationProperties的bean与更改日志level，那么如何做到的呢？结合官网文档我们来关注以下两个类：

　　ConfigurationPropertiesRebinder:

View Code

　　我们可以看到该类监听了ChangeEnvrionmentEvent事件，它最主要作用是拿到更新的配置以后，重新绑定@ConfigurationProperties标记的类使之能够读取最新的属性

　　LoggingRebinder:

View Code

　　该类也是监听了ChangeEnvrionmentEvent事件，用于重新绑定日志级别

回到顶部

二、刷新范围

　　我们考虑如下场景，当我们变更数据库配置后，通过refresh刷新，虽然能获取到最新的配置，可是我们的DataSource对象早就被初始化好了，换句话说即便配置刷新了我们拿到的依然是配置刷新前的对象。怎么解决这个问题呢？

　　我们继续看ContextRefresher的refresh方法，最后有一处代码值得我们关注一下this.scope.refreshAll()，此处scope对象是RefreshScope类型，那么这个类有什么作用呢？那么我们先要关注一下@RefreshScope注解。在这里我在贴出官网一段解释：

　　当配置更改时，标有@RefreshScope的Spring @Bean将得到特殊处理。这解决了状态bean在初始化时只注入配置的问题。例如，如果通过Environment更改数据库URL时DataSource有开放连接，那么我们可能希望这些连接的持有人能够完成他们正在做的工作。然后下一次有人从游泳池借用一个连接，他得到一个新的URL

　　　刷新范围bean是在使用时初始化的懒惰代理（即当调用一个方法时），并且作用域作为初始值的缓存。要强制bean重新初始化下一个方法调用，您只需要使其缓存条目无效。RefreshScope是上下文中的一个bean，它有一个公共方法refreshAll()来清除目标缓存中的范围内的所有bean。还有一个refresh(String)方法可以按名称刷新单个bean。此功能在/refresh端点（通过HTTP或JMX）中公开。

　　这里我贴出@RefreshScope源码：

View Code

　　在这个注解上我们关注一下此处标记了@Scope("refresh")，我们知道Spring的Bean属性有个叫scope的，它定义了bean的作用范围，常见的有singleon,prototype,session等。此处新定义了一个范围叫做refresh，在此我贴出RefreshScope的源代码来分析一下：

View Code

　　该类继承了GenericScope：

View Code

这里面我们先看一下RefreshScope的构造函数：

/**
     * Create a scope instance and give it the default name: "refresh".
     */
    public RefreshScope() {
        super.setName("refresh");
    }

　　这里面创建了一个名字为refresh的scope。

　　紧接着在它的父类里我们可以看一下这个方法：

　　 @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
            throws BeansException {
        this.beanFactory = beanFactory;
        beanFactory.registerScope(this.name, this);
        setSerializationId(beanFactory);
    }

　　此方法中使用BeanFactory注册了一个refresh的范围，使得scope为refresh的bean生效。@RefreshScope标注的类还有一个特点：会使用代理对象并进行延迟加载。我们来看一下postProcessBeanDefinitionRegistry方法

@Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry)
            throws BeansException {
        for (String name : registry.getBeanDefinitionNames()) {
            BeanDefinition definition = registry.getBeanDefinition(name);
            if (definition instanceof RootBeanDefinition) {
                RootBeanDefinition root = (RootBeanDefinition) definition;
                if (root.getDecoratedDefinition() != null && root.hasBeanClass()
                        && root.getBeanClass() == ScopedProxyFactoryBean.class) {
                    if (getName().equals(root.getDecoratedDefinition().getBeanDefinition()
                            .getScope())) {
                        root.setBeanClass(LockedScopedProxyFactoryBean.class);
                    }
                }
            }
        }
    }

　　该方法遍历所有的bean定义如果当前的bean的scope为refresh,那么就把当前的bean设置为 LockedScopedProxyFactoryBean的代理对象。

　　RefreshScope还会监听一个ContextRefreshedEvent，该事件会在ApplicationContext初始化或者refreshed时触发，我们来看一下代码：

　　 @EventListener
    public void start(ContextRefreshedEvent event) {
        if (event.getApplicationContext() == this.context && this.eager
                && this.registry != null) {
            eagerlyInitialize();
        }
    }
private void eagerlyInitialize() {
    for (String name : this.context.getBeanDefinitionNames()) {
        BeanDefinition definition = this.registry.getBeanDefinition(name);
        if (this.getName().equals(definition.getScope()) &amp;&amp; !definition.isLazyInit()) {
            Object bean = this.context.getBean(name);
            if (bean != null) {
                bean.getClass();
            }
        }
    }
}</pre>

　　注意此处获取refreshscope的bean，其中getBean是一个复杂而又繁琐的过程，此处我们先不在这里讨论，只不过经过这个方法以后，其通过代理机制会在GernericScope的BeanLifecycleWrapperCache缓存里把这个@RefreshScope标记的bean添加进去。

　　最后我们回过头来看一看RefreshScope的refreshAll方法：

    @ManagedOperation(description = "Dispose of the current instance of all beans in this scope and force a refresh on next method execution.")
    public void refreshAll() {
        super.destroy();
        this.context.publishEvent(new RefreshScopeRefreshedEvent());
    }
//.......GernericScope的destroy方法
@Override
public void destroy() {
    List&lt;Throwable&gt; errors = new ArrayList&lt;Throwable&gt;();
    Collection&lt;BeanLifecycleWrapper&gt; wrappers = this.cache.clear();
    for (BeanLifecycleWrapper wrapper : wrappers) {
        try {
            Lock lock = locks.get(wrapper.getName()).writeLock();
            lock.lock();
            try {
                wrapper.destroy();
            }
            finally {
                lock.unlock();
            }
        }
        catch (RuntimeException e) {
            errors.add(e);
        }
    }
    if (!errors.isEmpty()) {
        throw wrapIfNecessary(errors.get(0));
    }
    this.errors.clear();
}</pre>

　　这里的代码逻辑很简单清除与释放缓存里被@RefreshScope标记的bean 。

　　当我们要获取对象时，我们可以关注如下方法：

    @Override
    public Object get(String name, ObjectFactory<?> objectFactory) {
        BeanLifecycleWrapper value = this.cache.put(name,
                new BeanLifecycleWrapper(name, objectFactory));
        locks.putIfAbsent(name, new ReentrantReadWriteLock());
        try {
            return value.getBean();
        }
        catch (RuntimeException e) {
            this.errors.put(name, e);
            throw e;
        }
    }     
//.....  BeanLifecycleWrapper的方法
    public Object getBean() {
        if (this.bean == null) {
            synchronized (this.name) {
                if (this.bean == null) {
                    this.bean = this.objectFactory.getObject();
                }
            }
        }
        return this.bean;
    }            </pre>

BeanLifecycleWrapper这个是@RefreshScope标记bean的一个包装类，会被存储到缓存里，在这里取不到值的话就会从objectFactory里去拿

回到顶部

三、示例与总结

3.1、示例

　　创建AppConfig类代码如下：

package com.bdqn.lyrk.refresh.scope.server;
import org.springframework.boot.context.properties.EnableConfigurationProperties;

import org.springframework.cloud.context.config.annotation.RefreshScope;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;
@Configuration

@EnableConfigurationProperties(StudentConfig.class)

public class AppConfig {
@RefreshScope
@Bean
public Student student(StudentConfig config) {
    Student student = new Student();
    student.setName(config.getName());
    return student;
}

}

　　在这里，将Student设置为@RefreshScope 那么刷新以后会获取最新的Bean

　　启动类：

package com.bdqn.lyrk.refresh.scope.server;
import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication

@RestController

public class RefreshScopeApplication {
@Autowired
private Student student;

@GetMapping
public String student() {
    return student.getName();
}

public static void main(String[] args) throws InterruptedException {

    SpringApplication.run(RefreshScopeApplication.class, args);
}

}

　　application.yml文件：

spring:
  application:
    name: refresh-scope-server
endpoints:
  refresh:
    sensitive: false
server:
  port: 8089
student:
  name: admin

　　这里把refresh端点开放出来，然后变更配置后就可以获取最新的对象了

3.2、总结

　　1) 当配置更新并通过refresh端点刷新后，会执行ContextRefresher的refresh方法，该方法会记录当前的Environment，而后构建一个简易的SpringApplicationBuilder并执行其run方法，此时ConfigFileApplicationListener会读取我们修改过后的配置并绑定到SpringApplication对象上，最后进行changes操作来变更已有的PropertySource

　　2) @RefreshScope最好配合@Bean使用，当且仅当变更配置后，需要重新获取最新的bean时使用。加上该注解的Bean会被代理并且延迟加载，所有的scope属性为Refresh的bean会被包装成BeanLifecycleWrapper存入缓存(ConcurrentHashMap)中,所有的读取，修改，删除都是基于该缓存的

https://www.cnblogs.com/niechen/p/8979578.html

原文地址：https://www.cnblogs.com/softidea/p/10427041.html

posted @ 2019-07-16 09:43 星朝阅读(1402) 评论(0) 编辑收藏举报

刷新页面返回顶部

星朝

服务网关zuul----zuul中的动态刷新路由配置

重定向问题

java配置

修改路由

刷新

验证

深入理解SpringCloud之配置刷新

一、环境变化

1.1、关于ContextRefresher

1.2、addConfigFilesToEnvironment方法

1.3、changes方法

1.4、发布事件

二、刷新范围

三、示例与总结

3.1、示例

3.2、总结

公告