第四章 Spring CLoud 使用RestTemplate+Eureka调用用户微服务

上一篇讲到注册服务和用户服务，本章主要讲解一个服务调用另一个服务的方法：使用RestTemplate+eureka

项目结构如下：



SpringCloudOrderApplication类

package com.example.demo;

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

@SpringBootApplication
@EnableEurekaClient
public class SpringCloudOrderApplication {

@Bean	//必须new 一个RestTemplate并放入spring容器当中,否则启动时报错
public RestTemplate restTemplate() {
return new RestTemplate();
}

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

OrderController类

package com.example.demo.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import com.example.demo.entity.User;

@RestController
public class OrderController {
@Autowired
private RestTemplate restTemplate;

//获取application.yml里相应节点的值
@Value("${user.userServicePath}")
private String userServicePath;

@GetMapping("/order/{id}")
public User findById(@PathVariable Long id) {
return this.restTemplate.getForObject(this.userServicePath + id, User.class);
}
}

User类

package com.example.demo.entity;

import java.math.BigDecimal;

public class User {
private Long id;

private String username;

private String name;

private Short age;

private BigDecimal balance;

public Long getId() {
return this.id;
}

public void setId(Long id) {
this.id = id;
}

public String getUsername() {
return this.username;
}

public void setUsername(String username) {
this.username = username;
}

public String getName() {
return this.name;
}

public void setName(String name) {
this.name = name;
}

public Short getAge() {
return this.age;
}

public void setAge(Short age) {
this.age = age;
}

public BigDecimal getBalance() {
return this.balance;
}

public void setBalance(BigDecimal balance) {
this.balance = balance;
}

}

application.yml配置

spring:
application:
name: spring-cloud-order    #微服务的名称
server:
port: 7901  #微服务端口号
user:
userServicePath: http://localhost:7900/user/    #用户微服务的URL地址
eureka:
client:
healthcheck:
enabled: true   # 开启健康检查
serviceUrl:
defaultZone: http://user:123456@localhost:8761/eureka   #服务eureka的URL地址
instance:
prefer-ip-address: true

Pom.xml配置

<?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>

<groupId>com.example.demo</groupId>
<artifactId>spring-cloud-order</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>

<name>spring-cloud-order</name>
<description>spring-cloud-order</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.1.RELEASE</version>
</parent>

<properties>
<!-- 文件拷贝时的编码 -->
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<!-- 编译时的编码 -->
<maven.compiler.encoding>UTF-8</maven.compiler.encoding>
<!-- jdk版本 -->
<java.version>1.8</java.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- 注册中心 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<!-- 这个库让我们可以访问应用的很多信息,包括:/env、/info、/metrics、/health等 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!-- 用于热部署 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<!-- 版本依赖管理，故之后添加依赖无需指定version -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Camden.SR2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>

<build>
<plugins>
<!-- 用以为integration-test提供支持。 -->
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>

启动eureka服务，然后启动用户微服务和订单微服务，如下图所示：






注意，要是创建的项目报错，请点击项目右键：Maven----->Update Project

勾选Force Update of Snapshots/Releases即可