SpringCloud之Zuul：服务网关

Zuul在Web项目中的使用见上文《SpringBoot中使用Zuul》，下面例子为Zuul在Spring Cloud的使用。

开发工具：IntelliJ IDEA 2019.2.3

一、服务器端

1、创建项目

IDEA中创建一个新的SpringBoot项目，名称为“zuul-eureka-server”，SpringBoot版本选择2.1.10，在选择Dependencies(依赖)的界面勾选Spring Cloud Discovery -> Eureka Server。
pom.xml完整内容如下：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>zuul-eureka-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>zuul-eureka-server</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2、修改配置application.yml

修改端口号为8761；取消将自己信息注册到Eureka服务器，不从Eureka服务器抓取注册信息。

server:
  port: 8761
eureka:
  client:
    register-with-eureka: false
    fetch-registry: false

3、修改启动类代码

增加注解@EnableEurekaServer

package com.example.zuuleurekaserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class ZuulEurekaServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(ZuulEurekaServerApplication.class, args);
    }

}

二、服务提供者

1、创建项目

IDEA中创建一个新的SpringBoot项目，除了名称为“zuul-provider”，其它步骤和上面创建服务器端一样。

2、修改配置application.yml

server:
  port: 8000
spring:
  application:
    name: zuul-provider
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

3、添加一个实体类User.java

package com.example.zuulprovider;

public class User {
    String name;
    Integer age;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
}

4、修改启动类代码

package com.example.zuulprovider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@EnableEurekaClient
@RestController
public class ZuulProviderApplication {

    public static void main(String[] args) {
        SpringApplication.run(ZuulProviderApplication.class, args);
    }

    @RequestMapping(value="/user/{name}", produces = MediaType.APPLICATION_JSON_VALUE)
    public User user(@PathVariable String name) {
        User u = new User();
        u.setName(name);
        u.setAge(30);
        return u;
    }
}

三、服务调用者

1、创建项目

IDEA中创建一个新的SpringBoot项目，名称为“zuul-invoker”，SpringBoot版本选择2.1.10，在选择Dependencies(依赖)的界面勾选Spring Cloud Discovery -> Eureka Server，Spring Cloud Routing -> OpenFeign。
pom.xml完整内容如下：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>zuul-invoker</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>zuul-invoker</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2、修改配置application.yml

server:
  port: 9000
spring:
  application:
    name: zuul-invoker
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

3、添加一个实体类User.java

package com.example.zuulinvoker;

public class User {
    String name;
    Integer age;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
}

4、添加一个客户端接口UserClient.java

package com.example.zuulinvoker;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

//声明调用的服务名称
@FeignClient("zuul-provider")
public interface UserClient {
    @RequestMapping(method = RequestMethod.GET, value = "/user/{name}")
    User getUser(@PathVariable("name") String name);
}

5、修改启动类代码CloudInvokerApplication.java

加上注解@EnableEurekaClient和@EnableFeignClients

package com.example.zuulinvoker;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients
public class ZuulInvokerApplication {

    public static void main(String[] args) {
        SpringApplication.run(ZuulInvokerApplication.class, args);
    }

}

6、添加控制器 InvokerController.java

package com.example.zuulinvoker;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class InvokerController {
    @Autowired
    private UserClient userClient;

    @RequestMapping(value = "/invokeUser/{name}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
    public User invokeUser(@PathVariable String name){
        User user = userClient.getUser(name);
        return user;
    }
}

四、网关Zuul

1、创建项目
IDEA中创建一个新的SpringBoot项目，名称为“zuul-gateway”，SpringBoot版本选择2.1.10，在选择Dependencies(依赖)的界面勾选Spring Cloud Discovery -> Eureka Server，Spring Cloud Routing -> Zuul。
pom.xml完整内容如下：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>zuul-gateway</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>zuul-gateway</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</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>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2、修改启动类代码

增加注解@EnableZuulProxy

package com.example.zuulgateway;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableZuulProxy
public class ZuulGatewayApplication {

    public static void main(String[] args) {
        SpringApplication.run(ZuulGatewayApplication.class, args);
    }

}

3、修改配置application.yml

把网关项目注册到Eureka服务器中；
声明所有的/user/**请求会被转发到Id为zuul-invoker的服务进行处理。

server:
  port: 8080
spring:
  application:
    name: zuul-gateway
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
zuul:
  routes:
    user:
      path: /user/**
      serviceId: zuul-invoker

五、测试

1、启动服务器端。
浏览器访问http://localhost:8761/，正常
2、启动服务提供者
浏览器访问 http://localhost:8000/user/小明
页面输出：{"name":"小明","age":30}
3、启动服务调用者。
浏览器访问http://localhost:9000/invokeUser/小明
页面输出：{"name":"小明","age":30}
4、启动网关
http://localhost:8080/user/invokeUser/小明
页面输出：{"name":"小明","age":30}
由此可见，成功转发并处理。