Spring高级-容器接口-ApplicationContext的功能

ApplicationContext的实现类拥有不同的能力

EnvironmentCapable：整合 Environment 环境（能通过它获取各种来源的配置信息）
MessageSource： 国际化，提供一些针对不同语言翻译的能力
ResourcePatternResolver：通配符方式获取一组 Resource 资源
ApplicationEventPublisher：事件发布与监听，实现组件之间的解耦，类似于消息中间件

1 MessageSource（国际化）

放入资源

文件内容分别是

messages.properties 空

messages_en.properties hi=Hello

messages_ja.properties hi=こんにちは

messages_zh.properties hi=你好

代码

package com.mangoubiubiu.show;

import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultSingletonBeanRegistry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.MessageSource;
import org.springframework.core.env.EnvironmentCapable;
import org.springframework.core.io.support.ResourcePatternResolver;

import java.lang.reflect.Field;
import java.util.Locale;
import java.util.Map;

@Slf4j
@SpringBootApplication
public class ShowApplication {

    public static void main(String[] args) throws Exception {
        //返回的结果是Spring 容器
        ConfigurableApplicationContext context = SpringApplication.run(ShowApplication.class, args);

        System.out.println(context.getMessage("hi",null, Locale.CHINA));
        System.out.println(context.getMessage("hi",null, Locale.JAPANESE));
        System.out.println(context.getMessage("hi",null, Locale.ENGLISH));

    }

}

效果

上面ConfigurableApplicationContext 是 ApplicationContext的实现类一样也可以用MessageSource

2 ResourcePatternResolver（通配符方式获取一组 Resource 资源）

package com.mangoubiubiu.show;

import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultSingletonBeanRegistry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.MessageSource;
import org.springframework.core.env.EnvironmentCapable;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourcePatternResolver;

import java.lang.reflect.Field;
import java.util.Locale;
import java.util.Map;

@Slf4j
@SpringBootApplication
public class ShowApplication {

    public static void main(String[] args) throws Exception {
        //返回的结果是Spring 容器
        ConfigurableApplicationContext context = SpringApplication.run(ShowApplication.class, args);
        


        //Resource 是 Spring 中对文件的一个抽象
        Resource[] resources_yml = context.getResources("classpath:application.yml");
        for (Resource resource: resources_yml) {
            System.out.println(resource);
        }

        //classpath:META-INF/spring.factories  只是在类路径下找 在jar包里是找不到的
        //classpath*:META-INF/spring.factories  在jar里找要加*
        Resource[] resources = context.getResources("classpath*:META-INF/spring.factories");
        for (Resource resource: resources) {
            System.out.println(resource);
        }



    }

}

3 EnvironmentCapable 整合 Environment 环境（能通过它获取各种来源的配置信息）

package com.mangoubiubiu.show;

import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultSingletonBeanRegistry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.MessageSource;
import org.springframework.core.env.EnvironmentCapable;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourcePatternResolver;

import java.lang.reflect.Field;
import java.util.Locale;
import java.util.Map;

@Slf4j
@SpringBootApplication
public class ShowApplication {

    public static void main(String[] args) throws Exception {
        //返回的结果是Spring 容器
        ConfigurableApplicationContext context = SpringApplication.run(ShowApplication.class, args);
        
        //不区分大小写
        //系统环境变量
        System.out.println(context.getEnvironment().getProperty("java_home"));
        //配置信息
        System.out.println(context.getEnvironment().getProperty("server.port"));
        //启动参数
        System.out.println(context.getEnvironment().getProperty("env"));



    }

}

启动参数

4 ApplicationEventPublisher（事件发布与监听，实现组件之间的解耦，类似于消息中间件）

简单代码

package com.mangoubiubiu.show;

import org.springframework.context.ApplicationEvent;

public class UserRegisteredEvent extends ApplicationEvent {
    public UserRegisteredEvent(Object source) {
        super(source);
    }
}

package com.mangoubiubiu.show;

import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultSingletonBeanRegistry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.MessageSource;
import org.springframework.core.env.EnvironmentCapable;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourcePatternResolver;

import java.lang.reflect.Field;
import java.util.Locale;
import java.util.Map;

@Slf4j
@SpringBootApplication
public class ShowApplication {

    public static void main(String[] args) throws Exception {
        //返回的结果是Spring 容器
        ConfigurableApplicationContext context = SpringApplication.run(ShowApplication.class, args);


        //里面context 是事件源
        context.publishEvent(new UserRegisteredEvent(context));

    }

}

package com.mangoubiubiu.show;


import lombok.extern.slf4j.Slf4j;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Slf4j
@Component
public class Component1 {

    @EventListener
    public void aaa(UserRegisteredEvent event){
        log.info("这是Component1 监听到了事件{}",event);
    }

}

package com.mangoubiubiu.show;

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Slf4j
@Component
public class Compent2 {

    @EventListener
    public void aaa(UserRegisteredEvent event){
        log.info("这是Component2 监听到了事件{}",event);
    }
}

结合业务用户注册后发短信

事件发布类

package com.mangoubiubiu.show;


import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Slf4j
@Component
public class Component1 {

    @Autowired
    private ApplicationEventPublisher context;

    public void register(){
        log.info("用户注册");
        //注册后发布事件
        context.publishEvent(new UserRegisteredEvent(this));
    }

}

监听类：监听类可以写多个，且可以写不同的业务场景

package com.mangoubiubiu.show;

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Slf4j
@Component
public class Compent2 {

    @EventListener
    public void aaa(UserRegisteredEvent event){
        log.info("这是Component2 监听到了事件{}",event);
        log.info("发短信");

    }
}

调用类

package com.mangoubiubiu.show;

import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultSingletonBeanRegistry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.MessageSource;
import org.springframework.core.env.EnvironmentCapable;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourcePatternResolver;

import java.lang.reflect.Field;
import java.util.Locale;
import java.util.Map;

@Slf4j
@SpringBootApplication
public class ShowApplication {

    public static void main(String[] args) throws Exception {
        //返回的结果是Spring 容器
        ConfigurableApplicationContext context = SpringApplication.run(ShowApplication.class, args);


        context.getBean(Component1.class).register(); //获取bean 实例调用方法
    }

}

posted @ 2022-03-24 22:47 KwFruit 阅读(164) 评论(0) 编辑收藏举报

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