Spring Cloud 快速入门

文章参考于史上最简单的 SpringCloud 教程 | 终章

Spring Cloud 是一个微服务框架，与 Spring Boot 结合，开发简单。将一个大工程项目，分成多个小 web 服务工程，可以分别独立扩展，又可以共同合作。

环境

spring 官网的 sts 3.9.2，就是有spring 相关插件的eclipse；
apache maven 3.5.4，配置阿里云镜像
jdk1.8
Spring Cloud Finchley版本
Spring Boot 2.0.3

Spring Cloud 组件

服务注册中心、服务、断路器、配置中心

服务的注册与发现 - Eureka

使用 Eureka 来实现服务注册中心、服务提供者和服务消费者。

服务注册中心

一个服务注册中心，所有的服务都在注册中心注册，负载均衡也是通过在注册中心注册的服务来使用一定策略来实现。

1.新建一个 Spring Boot 工程，用来管理服务，elipse右键 -> new -> Spring Starter Project :

点击 next ，选择 Cloud Discovery 下的 Eureka Server 组件

生成的 pom 文件：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
<span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>com.beigege.cloud<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>eureka-server<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">version</span>&gt;</span>0.0.1-SNAPSHOT<span class="hljs-tag">&lt;/<span class="hljs-name">version</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">packaging</span>&gt;</span>jar<span class="hljs-tag">&lt;/<span class="hljs-name">packaging</span>&gt;</span>

<span class="hljs-tag">&lt;<span class="hljs-name">name</span>&gt;</span>eureka-server<span class="hljs-tag">&lt;/<span class="hljs-name">name</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">description</span>&gt;</span>spring cloud学习<span class="hljs-tag">&lt;/<span class="hljs-name">description</span>&gt;</span>

<span class="hljs-tag">&lt;<span class="hljs-name">parent</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>org.springframework.boot<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>spring-boot-starter-parent<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">version</span>&gt;</span>2.0.3.RELEASE<span class="hljs-tag">&lt;/<span class="hljs-name">version</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">relativePath</span> /&gt;</span> <span class="hljs-comment">&lt;!-- lookup parent from repository --&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">parent</span>&gt;</span>

<span class="hljs-tag">&lt;<span class="hljs-name">properties</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">project.build.sourceEncoding</span>&gt;</span>UTF-8<span class="hljs-tag">&lt;/<span class="hljs-name">project.build.sourceEncoding</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">project.reporting.outputEncoding</span>&gt;</span>UTF-8<span class="hljs-tag">&lt;/<span class="hljs-name">project.reporting.outputEncoding</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">java.version</span>&gt;</span>1.8<span class="hljs-tag">&lt;/<span class="hljs-name">java.version</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">spring-cloud.version</span>&gt;</span>Finchley.RELEASE<span class="hljs-tag">&lt;/<span class="hljs-name">spring-cloud.version</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">properties</span>&gt;</span>

<span class="hljs-tag">&lt;<span class="hljs-name">dependencies</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">dependency</span>&gt;</span>
        <span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>org.springframework.boot<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
        <span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>spring-boot-starter-test<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
        <span class="hljs-tag">&lt;<span class="hljs-name">scope</span>&gt;</span>test<span class="hljs-tag">&lt;/<span class="hljs-name">scope</span>&gt;</span>
    <span class="hljs-tag">&lt;/<span class="hljs-name">dependency</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">dependency</span>&gt;</span>
        <span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>org.springframework.cloud<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
        <span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>spring-cloud-starter-netflix-eureka-server<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
    <span class="hljs-tag">&lt;/<span class="hljs-name">dependency</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">dependencies</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">dependencyManagement</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">dependencies</span>&gt;</span>
        <span class="hljs-tag">&lt;<span class="hljs-name">dependency</span>&gt;</span>
            <span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>org.springframework.cloud<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
            <span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>spring-cloud-dependencies<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
            <span class="hljs-tag">&lt;<span class="hljs-name">version</span>&gt;</span>${spring-cloud.version}<span class="hljs-tag">&lt;/<span class="hljs-name">version</span>&gt;</span>
            <span class="hljs-tag">&lt;<span class="hljs-name">type</span>&gt;</span>pom<span class="hljs-tag">&lt;/<span class="hljs-name">type</span>&gt;</span>
            <span class="hljs-tag">&lt;<span class="hljs-name">scope</span>&gt;</span>import<span class="hljs-tag">&lt;/<span class="hljs-name">scope</span>&gt;</span>
        <span class="hljs-tag">&lt;/<span class="hljs-name">dependency</span>&gt;</span>
    <span class="hljs-tag">&lt;/<span class="hljs-name">dependencies</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">dependencyManagement</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">build</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">plugins</span>&gt;</span>
        <span class="hljs-tag">&lt;<span class="hljs-name">plugin</span>&gt;</span>
            <span class="hljs-tag">&lt;<span class="hljs-name">groupId</span>&gt;</span>org.springframework.boot<span class="hljs-tag">&lt;/<span class="hljs-name">groupId</span>&gt;</span>
            <span class="hljs-tag">&lt;<span class="hljs-name">artifactId</span>&gt;</span>spring-boot-maven-plugin<span class="hljs-tag">&lt;/<span class="hljs-name">artifactId</span>&gt;</span>
        <span class="hljs-tag">&lt;/<span class="hljs-name">plugin</span>&gt;</span>
    <span class="hljs-tag">&lt;/<span class="hljs-name">plugins</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">build</span>&gt;</span>

</project>

2.使用 @EnableEurekaServer 来说明项目是一个 Eureka：

@SpringBootApplication

@EnableEurekaServer

public class EurekaServerApplication {
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> main(String[] args) {
    SpringApplication.run(EurekaServerApplication.<span class="hljs-keyword">class</span>, args);
}

}

3.修改配置文件，配置文件，可以是 application.properties 或 application.yml，这里改后缀，使用 yml，两种格式内容都是一样的只是格式不同 application.yml：

server: port: 8761 #服务端口 spring: application: name: eurka-server #服务应用名称

eureka: instance: hostname: localhost client: registerWithEureka: false #是否将自己注册到Eureka Server，默认为true fetchRegistry: false #是否从Eureka Server获取注册信息，默认为true service-url: defaultZone: http://${eureka.instance.hostname}😒{server.port}/eureka/ #服务注册的 URL

默认 eureka server 也是一个 eureka client，registerWithEureka: false 和 fetchRegistry: false 来表明项目是一个 Eureka Server。

4.运行 EurekaServerApplication 类，启动项目，访问项目 http://localhost:8761/

服务提供者

1.新建项目名为 eureka-client 的 Spring Boot 项目，跟 Eureka Server 新建一样，只是在选择 Spring Boot 组件的时候，不选 Eureka Server ，选择 Eureka Client，这里为了测试，再添加一个 Web 下的 Web 组件：

2.修改配置，application.yml:

server: port: 8762 spring: application: name: service-hi #服务之间的调用都是根据这个 name

eureka: client: service-url: defaultZone: http://localhost:8761/eureka/

3.添加 @EnableEurekaClient 注解，并添加一个测试接口 /hi：

@SpringBootApplication

@EnableEurekaClient

@RestController

public class EurekaClientApplication {
<span class="hljs-keyword">public</span> static void main(String[] args) {
    SpringApplication.run(EurekaClientApplication.<span class="hljs-keyword">class</span>, args);
}

<span class="hljs-meta">@Value(<span class="hljs-meta-string">"<span class="hljs-subst">${server.port}</span>"</span>)</span>
String port;

<span class="hljs-meta">@RequestMapping(<span class="hljs-meta-string">"/hi"</span>)</span>
<span class="hljs-keyword">public</span> String home(<span class="hljs-meta">@RequestParam(value = <span class="hljs-meta-string">"name"</span>, defaultValue = <span class="hljs-meta-string">"beigege"</span>)</span> String name) {
    <span class="hljs-keyword">return</span> <span class="hljs-string">"hi "</span> + name + <span class="hljs-string">" ,i am from port:"</span> + port;
}

}

4.启动 Eureka Server 和 Eureka Client 项目，访问http://localhost:8761 ，即eureka server 的网址：

服务消费者 - Ribbon | Feign

Spring Cloud 两种调用服务的方式，ribbon + restTemplate，和 feign。

Ribbon

ribbon 在客户端实现了负载均衡。

启动 Eureka Server 和 Eureka Client，修改 Eureka Client 端口，再启动一个 Eureka Client 实例，相当于一个小的集群，访问localhost:8761

1.新建一个 spring boot 工程，名称为 service-ribbon，创建过程和 eureka-client 一样，组件多选一个 Cloud Routing 下的 Ribbon，创建完成之后的 pom 文件依赖：

server: port: 8764 spring: application: name: service-ribbon

eureka: client: service-url: defaultZone: http://localhost:8761/eureka/

ServiceRibbonApplication 加上 @EnableEurekaClient 注解

2.向 Spring 注入一个 bean: restTemplate，并添加 @LoadBalanced 注解，表明这个 restTemplate 开启负载均衡功能：

@SpringBootApplication

@EnableEurekaClient

public class ServiceRibbonApplication {
<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">main</span><span class="hljs-params">(String[] args)</span> </span>{
    SpringApplication.run(ServiceRibbonApplication.class, args);
}

<span class="hljs-meta">@Bean</span>
<span class="hljs-meta">@LoadBalanced</span>
<span class="hljs-function">RestTemplate <span class="hljs-title">restTemplate</span><span class="hljs-params">()</span> </span>{
    <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> RestTemplate();
}

}

3.写一个接口用来调用之前的 service-hi 服务的 /hi 接口：
新建 service 层，名叫 HelloService，调用 /hi 接口，这里用服务名 SERVICE-HI 代替具体的 URL：

@Service

public class HelloService {
<span class="hljs-meta">@Autowired</span>
RestTemplate restTemplate;

<span class="hljs-keyword">public</span> <span class="hljs-built_in">String</span> hiService(<span class="hljs-built_in">String</span> name) {
    <span class="hljs-keyword">return</span> restTemplate.getForObject(<span class="hljs-string">"http://SERVICE-HI/hi?name="</span>+name,<span class="hljs-built_in">String</span>.class);
}

}

新建 controller 层，调用 service 层：

@RestController

public class HelloControler {
<span class="hljs-meta">@Autowired</span>
HelloService helloService;
<span class="hljs-meta">@RequestMapping(value = <span class="hljs-meta-string">"/hi"</span>)</span>
<span class="hljs-keyword">public</span> String hi(<span class="hljs-meta">@RequestParam</span> String name){
    <span class="hljs-keyword">return</span> helloService.hiService(name);
}

}

4.启动 service-ribbon 工程，多次访问该工程的 /hi 接口，即 localhost:8764/hi?name=test：

hi test ,i am from port:8762
hi test ,i am from port:8763

上面交替显示，说明实现了负载均衡，ribbon 会在客户端发送请求时做一个负载均衡。

Feign

整合了 Ribbon，具有负载均衡的能力，整合了Hystrix，具有熔断的能力.

1.创建一个 spring boot工程，创建过程和 eureka-client 一样，多添加一个组件 Cloud Routing 下的 Feign，项目名叫 service-feign，创建完后的 pom 文件依赖：

server: port: 8765 spring: application: name: service-feign

eureka: client: serviceUrl: defaultZone: http://localhost:8761/eureka/

SericeFeignApplication 上添加 @EnableEurekaClient 和 @EnableFeignClients 注解：

@SpringBootApplication

@EnableEurekaClient

@EnableFeignClients

public class SericeFeignApplication {
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> main(String[] args) {
    SpringApplication.run(SericeFeignApplication.<span class="hljs-keyword">class</span>, args);
}

}

2.写一个 SchedualServiceHi 接口，通过@ FeignClient（“服务名”），来指定调用哪个服务，@GetMapping("接口名")，来向接口发送 Get 请求，@RequestParam 是请求参数：

@FeignClient(value = "service-hi")

public interface SchedualServiceHi {
<span class="hljs-meta">@GetMapping(<span class="hljs-meta-string">"/hi"</span>)</span>
String sayHiFromClientOne(<span class="hljs-meta">@RequestParam(value = <span class="hljs-meta-string">"name"</span>)</span> String name);

}

写一个 controller 层测试 SchedualServiceHi 接口：

@RestController

public class HiController {
<span class="hljs-meta">@Autowired</span>
SchedualServiceHi schedualServiceHi;

<span class="hljs-meta">@GetMapping(value = <span class="hljs-meta-string">"/hi"</span>)</span>
<span class="hljs-keyword">public</span> String sayHi(<span class="hljs-meta">@RequestParam</span> String name) {
    <span class="hljs-keyword">return</span> schedualServiceHi.sayHiFromClientOne( name );
}

}

3.启动 service-feign，访问localhost:8765/hi?name=test 测试，下面交替显示，说明实现了负载均衡：

hi test ,i am from port:8762
hi test ,i am from port:8763

断路器 - Hystrix

链式调用服务，其中一个服务宕机，其他服务可能会跟着异常，发生雪崩，当对一个服务的调用失败次数到达一定阈值，断路器会打开，执行服务调用失败时的处理，避免连锁故障，上面已经启动：eureka-server、两个 eureka-client 实例、service-ribbon 和 service-feign，下面继续修改，分别在 service-ribbon 和 service-feign 上实现断路器。

service-ribbon + Hystrix

1.在 pom 文件中加入 Hystrix 依赖：

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>

2.在程序的启动类 ServiceRibbonApplication 加 @EnableHystrix 注解开启Hystrix：

@SpringBootApplication

@EnableEurekaClient

@EnableHystrix

public class ServiceRibbonApplication {
<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">main</span><span class="hljs-params">(String[] args)</span> </span>{
    SpringApplication.run( ServiceRibbonApplication.class, args );
}

<span class="hljs-meta">@Bean</span>
<span class="hljs-meta">@LoadBalanced</span>
<span class="hljs-function">RestTemplate <span class="hljs-title">restTemplate</span><span class="hljs-params">()</span> </span>{
    <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> RestTemplate();
}

}

3.添加熔断方法，改造 HelloService 类，在 hiService 方法上面添加 @HystrixCommand 注解，fallbackMethod 是熔断方法，当服务不可用时会执行，该方法，即 hiError 方法：

@Service

public class HelloService {
<span class="hljs-meta">@Autowired</span>
RestTemplate restTemplate;

<span class="hljs-meta">@HystrixCommand</span>(fallbackMethod = <span class="hljs-string">"hiError"</span>)
<span class="hljs-keyword">public</span> <span class="hljs-built_in">String</span> hiService(<span class="hljs-built_in">String</span> name) {
    <span class="hljs-keyword">return</span> restTemplate.getForObject(<span class="hljs-string">"http://SERVICE-HI/hi?name="</span>+name,<span class="hljs-built_in">String</span>.class);
}

<span class="hljs-keyword">public</span> <span class="hljs-built_in">String</span> hiError(<span class="hljs-built_in">String</span> name) {
    <span class="hljs-keyword">return</span> <span class="hljs-string">"hi,"</span>+name+<span class="hljs-string">",sorry,error!"</span>;
}

}

重启 service-ribbon，访问 localhost:8764/hi?name=test

hi test ,i am from port:8763

关闭两个 eureka-client 实例，在访问 localhost:8764/hi?name=test，浏览器显示：

hi,test,sorry,error!

当服务不可用时，断路器会迅速执行熔断方法

service-feign + Hystrix

1.Feign 自带断路器，在D版本的Spring Cloud之后，它没有默认打开。需要在配置文件中配置打开：

feign: 
  hystrix: 
    enabled: true

2.在请求接口指定熔断实现类，fallback 指定熔断实现类：

@FeignClient(value ="service-hi",fallback = SchedualServiceHiHystric.class)

public interface SchedualServiceHi {
<span class="hljs-meta">@GetMapping(<span class="hljs-meta-string">"/hi"</span>)</span>
String sayHiFromClientOne(<span class="hljs-meta">@RequestParam(value = <span class="hljs-meta-string">"name"</span>)</span> String name);

}

SchedualServiceHiHystric 类实现 SchedualServiceHi 接口：

@Component

public class SchedualServiceHiHystric implements SchedualServiceHi{
<span class="hljs-meta">@Override</span>
<span class="hljs-function"><span class="hljs-keyword">public</span> String <span class="hljs-title">sayHiFromClientOne</span><span class="hljs-params">(String name)</span> </span>{
    <span class="hljs-keyword">return</span> <span class="hljs-string">"sorry "</span>+name;
}

}

3.访问测试，重启 service-feign，访问 localhost:8765/hi?name=test:

sorry test

打开 eureka-client，再次访问 localhost:8765/hi?name=test:

hi test ,i am from port:8762

证明断路器起到作用，注意浏览器缓存。

路由网关 - Zuul

1.创建一个 spring boot 工程，名称为 service-zuul，创建过程和 eureka-client 一样，组件要多添加一个 Cloud Routing 下的 Zuul，pom 文件的依赖如下：

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

2.在入口 application 中添加 @EnableZuulProxy 注解，开启路由：

@SpringBootApplication

@EnableEurekaClient

@EnableZuulProxy

public class ServiceZuulApplication {
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> main(String[] args) {
    SpringApplication.run(ServiceZuulApplication.<span class="hljs-keyword">class</span>, args);
}

}

application.yml 配置：

server: port: 8769 spring: application: name: service-zuul

eureka: client: serviceUrl: defaultZone: http://localhost:8761/eureka/

添加路由

修改 application.yml 添加路由配置：

server: port: 8769 spring: application: name: service-zuul eureka: client: serviceUrl: defaultZone: http://localhost:8761/eureka/

zuul: routes: api-a: path: /api-a/ service-id: service-ribbon api-b: path: /api-b/ service-id: service-feign

8769 端口的所有 api-a 请求会转发到 service-ribbon 工程，api-b 到 service-feign

启动 service-zuul，访问 localhost:8769/api-a/hi?name=test，浏览器显示：

hi test ,i am from port:8762

访问 localhost:8769/api-b/hi?name=test，浏览器显示：

hi test ,i am from port:8762

说明路由成功。

过滤器

新建自定义过滤器，继承 ZuulFilter：

@Component

public class MyFilter extends ZuulFilter {
<span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> Logger log = LoggerFactory.getLogger(MyFilter.class);

<span class="hljs-comment">/*
 * filterType：返回一个字符串代表过滤器的类型，在zuul中定义了四种不同生命周期的过滤器类型，具体如下：
 * pre：路由之前
 * routing：路由之时 
 * post： 路由之后 
 * error：发送错误调用 
 */</span>
<span class="hljs-meta">@Override</span>
<span class="hljs-function"><span class="hljs-keyword">public</span> String <span class="hljs-title">filterType</span><span class="hljs-params">()</span> </span>{
    <span class="hljs-keyword">return</span> <span class="hljs-string">"pre"</span>;
}

<span class="hljs-comment">/*
 * filterOrder：过滤的顺序
 */</span>
<span class="hljs-meta">@Override</span>
<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">int</span> <span class="hljs-title">filterOrder</span><span class="hljs-params">()</span> </span>{
    <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
}

<span class="hljs-comment">/*
 * shouldFilter：这里可以写逻辑判断，是否要过滤，本文true,永远过滤。
 */</span>
<span class="hljs-meta">@Override</span>
<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">boolean</span> <span class="hljs-title">shouldFilter</span><span class="hljs-params">()</span> </span>{
    <span class="hljs-keyword">return</span> <span class="hljs-keyword">true</span>;
}

<span class="hljs-comment">/*
 * run：过滤器的具体逻辑。可以很复杂，包括查sql，nosql去判断该请求到底有没有权限访问，
 * 这里是判断请求有没有 token 参数
 */</span>
<span class="hljs-meta">@Override</span>
<span class="hljs-function"><span class="hljs-keyword">public</span> Object <span class="hljs-title">run</span><span class="hljs-params">()</span> </span>{
    RequestContext ctx = RequestContext.getCurrentContext();
    HttpServletRequest request = ctx.getRequest();
    log.info(String.format(<span class="hljs-string">"%s &gt;&gt;&gt; %s"</span>, request.getMethod(), request.getRequestURL().toString()));
    Object accessToken = request.getParameter(<span class="hljs-string">"token"</span>);
    <span class="hljs-keyword">if</span>(accessToken == <span class="hljs-keyword">null</span>) {
        log.warn(<span class="hljs-string">"token is empty"</span>);
        ctx.setSendZuulResponse(<span class="hljs-keyword">false</span>);
        ctx.setResponseStatusCode(<span class="hljs-number">401</span>);
        <span class="hljs-keyword">try</span> {
            ctx.getResponse().getWriter().write(<span class="hljs-string">"token is empty"</span>);
        }<span class="hljs-keyword">catch</span> (Exception e){}

        <span class="hljs-keyword">return</span> <span class="hljs-keyword">null</span>;
    }
    log.info(<span class="hljs-string">"ok"</span>);
    <span class="hljs-keyword">return</span> <span class="hljs-keyword">null</span>;
}

}

重启 service-zuul 访问 localhost:8769/api-a/hi?name=test，浏览器显示