restTemplate方式实现springcloud项目初探

一般需要三个项目，注册中心也就是Eureka注册中心项目，服务的调用方和服务的接口提供方。

1.首先新建maven工程，eureka-server项目

新建完毕，引入pom依赖

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <!--eureka server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
        <!-- spring boot test -->
        <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>Dalston.RC1</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>
    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>

然后配置yml配置文件
/eureka-server/src/main/resources/application.yml
配置文件内容如下

server:
  port: 8888        端口号
eureka:
  instance:
    hostname: localhost     启动地址，这里默认为本地
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/     eureka注册中心地址

然后创建启动类（注意注解要使用正确）
EurekaApp.java

package com.lwq;

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

@SpringBootApplication
@EnableEurekaServer 
public class EurekaApp {
    public static void main(String[] args) {
        SpringApplication.run(EurekaApp.class, args);
    }

}

启动项目，访问http://localhost:8888/成功访问说明配置正确

2.创建服务提供者，即service-member（这里一会员服务为例）

同样，创建工程需要引入maven依赖

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</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>Dalston.RC1</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>
    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>

然后引入配置文件application.yml

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8888/eureka/      此处为eureka本地工程地质
server:
  port: 8762
spring:
  application:
    name: service-member        此处为服务调用的名称

创建启动类MemberApp.java

package com.lwq;

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

@SpringBootApplication
@EnableEurekaClient       //注意这里是client，而注册中心那里是 server
public class MemberApp {

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

    }

}

创建接口服务
MemberController.java

package com.lwq;

import java.util.ArrayList;
import java.util.List;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MemberController {

    @RequestMapping("/getUserList")
    public List<String> getUserList() {
        List<String> listUser = new ArrayList<String>();
        listUser.add("zhangsan");
        listUser.add("lisi");
        listUser.add("wangwu");
        return listUser;
    }
}

启动查看eureka注册中心会出现有服务注册成功

image.png

此时访问项目地址就可以成功返回

image.png

3.下面我们创建服务的调用者 service-order服务，通过rest方式进行调用

创建完毕引入依赖

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

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

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</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>Dalston.RC1</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>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>

引入yml文件

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8888/eureka/
server:
  port: 8764
spring:
  application:
    name: service-order

创建启动类OrderApp.java

package com.lwq;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
public class OrderApp {

    public static void main(String[] args) {
        SpringApplication.run(OrderApp.class, args);
    }
    
    /**
     * 启用rest方法进行调用
     * @return
     */
    @Bean
    @LoadBalanced //允许负载均衡
    RestTemplate restTemplate() {
        return new RestTemplate();
    }

}

编写service,调用service-member

@SuppressWarnings("unchecked")
@Service
public class MemberService {
    @Autowired
    RestTemplate restTemplate;

    public List<String> getOrderByUserList() { 
        //这里直接写服务提供者的名称即可
        return restTemplate.getForObject("http://service-member/getUserList", List.class);
    }   
}

创建controller类型进行调用完成正确返回信息

package com.lwq;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class OrderController {

    @Autowired
    private MemberService memberService;
    
    @RequestMapping("getOrderByUserList")
    public List<String> getOrderByUserList() {
        return memberService.getOrderByUserList();
    }
}

小提示：注意三个项目的启动顺序，一定要是eureka项目首先启动，不然无法完成注册会报错