使用Resttemplate和Ribbon调用Eureka实现负载均衡

1.服务注册和发现Eureka，可以用作服务治理。

2.首先我们建立一个父子工程

最外层是forezp

其下面建立四个子工程

eureka-server

eureka-client

eureka-client1

eureka-ribbon-client

4.forezp工程相关

1.forezp pom文件如下

<?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 http://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>2.1.5.RELEASE</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.example</groupId>
   <artifactId>forezp</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>forezp</name>
   <description>Demo project for Spring Boot</description>


   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
      <java.version>1.8</java.version>
      <spring-cloud.version>Dalston.SR1</spring-cloud.version>
   </properties>


   <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>


   <modules>
      <module>euraka-client</module>
      <module>euraka-server</module>
      <module>eureka-ribbon-client</module>
      <module>euraka-client2</module>
   </modules>


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


</project>

5.Eureka的服务中心：eureka-server相关

1.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>
   <parent>
      <groupId>com.example</groupId>
      <artifactId>forezp</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.example</groupId>
   <artifactId>euraka-server</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>euraka-server</name>
   <description>Demo project for Spring Boot</description>


   <properties>
      <java.version>1.8</java.version>
      <spring-cloud.version>Greenwich.SR1</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.application.properties文件

server.port=8761

eureka.instance.hostname=localhost

#防止自己注册自己
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
#eureka的注册地址
eureka.client.service-url.default-zone=http://${eureka.instance.hostname}:${server.port}/eureka/}

3.需要在启动类添加 @EnableEurekaServer 注解来开启注册服务

package com.example.eurakaserver;


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


@SpringBootApplication
@EnableEurekaServer
public class EurakaServerApplication {


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


}

6.eureka-client和eureka-client1用来提供服务，这两个子工程其实区别不大，只是为了验证实现负载均衡。

1.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>
	<parent>
		<groupId>com.example</groupId>
		<artifactId>forezp</artifactId>
		<version>0.0.1-SNAPSHOT</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>euraka-client2</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>euraka-client2</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Greenwich.SR1</spring-cloud.version>
	</properties>

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

		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</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.新建一个ApiController类

package com.example.eurakaclient2;


import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;


@RestController
public class ApiController {


    @Value("${server.port}")
    String port;
    @GetMapping("/hi")
    public String home(@RequestParam String name1){
        return "hi "+name1+"i am a port:"+port;
    }
}

3.eureka-client 的 apllication.properties配置如下

eureka.client.service-url.defaultZone=http://localhost:8761/eureka/
server.port=8762
spring.application.name=eureka-client

4.eureka-client2的 apllication.properties配置如下

eureka.client.service-url.defaultZone=http://localhost:8761/eureka/
server.port=8763
spring.application.name=eureka-client

5.需要在启动类添加注解 @EnableEurekaClient，开启服务提供

package com.example.eurakaclient2;


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


@SpringBootApplication
@EnableEurekaClient
public class EurakaClient2Application {


   public static void main(String[] args) {
      SpringApplication.run(EurakaClient2Application.class, args);
   }


}

7.eureka-ribbon-client工程相关

1.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>
   <parent>
      <groupId>com.example</groupId>
      <artifactId>forezp</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.example</groupId>
   <artifactId>eureka-ribbon-client</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>eureka-ribbon-client</name>
   <description>Demo project for Spring Boot</description>


   <properties>
      <java.version>1.8</java.version>
      <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
   </properties>


   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.cloud</groupId>
         <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
      </dependency>


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


      <dependency>
         <groupId>org.projectlombok</groupId>
         <artifactId>lombok</artifactId>
         <optional>true</optional>
      </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.applicaiton.properties配置文件如下

spring.application.name=eureka-ribbon-client
server.port=8764
eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

3.新建RibbonConfig类，在这里注入RestTemplate类同时开启负载均衡

package com.example.eurekaribbonclient;


import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;


@Configuration
public class RibbonConfig {


    @Bean
    @LoadBalanced
    RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

4.新建service层，调用eureka-client （eureka-client1）提供的restful接口，其中 eureka-client 为 eureka-client （eureka-client1）注册在 eureka-service上的serviceId信息，如果没有配置serviceId,默认使用spring.application.name

package com.example.eurekaribbonclient;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;




    @Service
    public class RibbonService {
        @Autowired
    RestTemplate restTemplate;
    public String hi(String name){


        return restTemplate.getForObject("http://eureka-client/hi?name1="+name,String.class);
    }
}

5.新建controller层，调用RibbonService为我们提供的方法

package com.example.eurekaribbonclient;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;


@RestController
public class RibbonController {
    @Autowired
    RibbonService ribbonService;


    @GetMapping("/hi")
    public String hi(@RequestParam(required = false,defaultValue = "forezp")String name){
        return ribbonService.hi(name);
    }
}

6.同时也需要在启动类添加@EnableEurekaClient注解

package com.example.eurekaribbonclient;


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


@SpringBootApplication
@EnableEurekaClient
public class EurekaRibbonClientApplication {


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


}

8.验证

1.按照顺序启动工程

2.浏览器访问 http://localhost:8761/

可以看到EUREKA-CLIENT 和 EUREKA-RIBBON-CLIENT已经注册进来了

使用Resttemplate和Ribbon调用Eureka实现负载均衡

3.我们访问 http://localhost:8764/hi?name=forezp 两次

可以看到页面分别返回

hi forezpi am a port:8762

hi forezpi am a port:8763

这样验证了我们实现了负载均衡。

使用Resttemplate和Ribbon调用Eureka实现负载均衡

1.服务注册和发现Eureka，可以用作服务治理。

2.首先我们建立一个父子工程

4.forezp工程相关

5.Eureka的服务中心：eureka-server相关

6.eureka-client和eureka-client1用来提供服务，这两个子工程其实区别不大，只是为了验证实现负载均衡。

7.eureka-ribbon-client工程相关

8.验证

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