如何使用Resttemplate和Ribbon呼叫Eureka實現負載均衡

2022-03-26 19:01:54

1.服務註冊和發現Eureka

可以用作服務治理。

2.首先我們建立一個父子工程

最外層是forezp

其下面建立四個子工程

eureka-server
eureka-client
eureka-client1
eureka-ribbon-client

3.forezp工程相關

1.forezp pom檔案如下

<?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>

4.Eureka的服務中心:eureka-server相關

1.pom檔案

<?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檔案

server.port=8761 
eureka.instance.hostname=localhost
 
#防止自己註冊自己
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
#eureka的註冊地址
eureka.client.service-url.default-zone=http://${eureka.instance.hostname}:${server.port}/eureka/}

3.需要在啟動類新增 @EnableEurekaServer 註解來開啟註冊服務

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);
   }  
}

5.eureka-client和eureka-client1用來提供服務

這兩個子工程其實區別不大，只是為了驗證實現負載均衡。

1.pom檔案

<?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.新建一個ApiController類

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設定如下

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

4.eureka-client2的 apllication.properties設定如下

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

5.需要在啟動類新增註解 @EnableEurekaClient，開啟服務提供

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);
   } 
}

6.eureka-ribbon-client工程相關

1.pom檔案

<?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組態檔如下

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

3.新建RibbonConfig類，在這裡注入RestTemplate類同時開啟負載均衡

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層，呼叫eureka-client （eureka-client1）提供的restful介面，其中 eureka-client 為 eureka-client （eureka-client1）註冊在 eureka-service上的serviceId資訊，如果沒有設定serviceId,預設使用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層，呼叫RibbonService為我們提供的方法

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.同時也需要在啟動類新增@EnableEurekaClient註解

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);
   }  
}