開發環境：IntelliJ IDEA 2019.2.2Spring Boot版本：2.1.8

一、發布REST服務

1、IDEA新建一個名稱為rest-server的Spring Boot項目

2、新建一個實體類User.java

package com.example.restserver.domain;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; }}

3、新建一個控制器類 UserController.java

package com.example.restserver.web;import com.example.restserver.domain.User;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;@RestControllerpublic class UserController { @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; }}

項目結構如下：

訪問http://localhost:8080/user/lc，頁面顯示：

{'name':'lc','age':30}

二、使用RestTemplae調用服務

1、IDEA新建一個名稱為rest-client的Spring Boot項目

2、新建一個含有main方法的普通類RestTemplateMain.java，調用服務

package com.example.restclient;import com.example.restclient.domain.User;import org.springframework.web.client.RestTemplate;public class RestTemplateMain { public static void main(String[] args){ RestTemplate tpl = new RestTemplate(); User u = tpl.getForObject('http://localhost:8080/user/lc', User.class); System.out.println(u.getName() + ',' + u.getAge()); }}

右鍵Run ’RestTemplateMain.main()’，控制臺輸出：lc,30

3、在bean里面使用RestTemplate，可使用RestTemplateBuilder，新建類UserService.java

package com.example.restclient.service;import com.example.restclient.domain.User;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.web.client.RestTemplateBuilder;import org.springframework.context.annotation.Bean;import org.springframework.stereotype.Service;import org.springframework.web.client.RestTemplate;@Servicepublic class UserService { @Autowired private RestTemplateBuilder builder; @Bean public RestTemplate restTemplate(){ return builder.rootUri('http://localhost:8080').build(); } public User userBuilder(String name){ User u = restTemplate().getForObject('/user/' + name, User.class); return u; }}

4、編寫一個單元測試類，來測試上面的UserService的bean。

package com.example.restclient.service;import com.example.restclient.domain.User;import org.junit.Assert;import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import org.springframework.test.context.junit4.SpringRunner;@RunWith(SpringRunner.class)@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.NONE)public class UserServiceTest { @Autowired private UserService userService; @Test public void testUser(){ User u = userService.userBuilder('lc'); Assert.assertEquals('lc', u.getName()); }}

5、控制器類UserController.cs 中調用

配置在application.properties 配置端口和8080不一樣，如server.port = 9001

@Autowired private UserService userService; @RequestMapping(value='/user/{name}', produces = MediaType.APPLICATION_JSON_VALUE) public User user(@PathVariable String name) { User u = userService.userBuilder(name); return u; }

三、使用Feign調用服務

繼續在rest-client項目基礎上修改代碼。

1、pom.xml添加依賴

<dependency> <groupId>io.github.openfeign</groupId> <artifactId>feign-core</artifactId> <version>9.5.0</version> </dependency> <dependency> <groupId>io.github.openfeign</groupId> <artifactId>feign-gson</artifactId> <version>9.5.0</version> </dependency>

2、新建接口UserClient.java

package com.example.restclient.service;import com.example.restclient.domain.User;import feign.Param;import feign.RequestLine;public interface UserClient { @RequestLine('GET /user/{name}') User getUser(@Param('name')String name);}

3、在控制器類UserController.java 中調用

decoder(new GsonDecoder()) 表示添加了解碼器的配置，GsonDecoder會將返回的JSON字符串轉換為接口方法返回的對象。相反的，encoder(new GsonEncoder())則是編碼器，將對象轉換為JSON字符串。

@RequestMapping(value='/user2/{name}', produces = MediaType.APPLICATION_JSON_VALUE) public User user2(@PathVariable String name) { UserClient service = Feign.builder().decoder(new GsonDecoder()) .target(UserClient.class, 'http://localhost:8080/'); User u = service.getUser(name); return u; }

4、優化第3步代碼，并把請求地址放到配置文件中。

（1）application.properties 添加配置

復制代碼 代碼如下:application.client.url = http://localhost:8080

（2）新建配置類ClientConfig.java

package com.example.restclient.config;import com.example.restclient.service.UserClient;import feign.Feign;import feign.gson.GsonDecoder;import org.springframework.beans.factory.annotation.Value;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configurationpublic class ClientConfig { @Value('${application.client.url}') private String clientUrl; @Bean UserClient userClient(){ UserClient client = Feign.builder().decoder(new GsonDecoder()).target(UserClient.class, clientUrl); return client; }}

（3）控制器 UserController.java 中調用

@Autowired private UserClient userClient; @RequestMapping(value='/user3/{name}', produces = MediaType.APPLICATION_JSON_VALUE) public User user3(@PathVariable String name) { User u = userClient.getUser(name); return u; }

UserController.java最終內容：

package com.example.restclient.web;import com.example.restclient.domain.User;import com.example.restclient.service.UserClient;import com.example.restclient.service.UserService;import feign.Feign;import feign.gson.GsonDecoder;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.RestController;@RestControllerpublic class UserController { @Autowired private UserService userService; @Autowired private UserClient userClient; @RequestMapping(value='/user/{name}', produces = MediaType.APPLICATION_JSON_VALUE) public User user(@PathVariable String name) { User u = userService.userBuilder(name); return u; } @RequestMapping(value='/user2/{name}', produces = MediaType.APPLICATION_JSON_VALUE) public User user2(@PathVariable String name) { UserClient service = Feign.builder().decoder(new GsonDecoder()) .target(UserClient.class, 'http://localhost:8080/'); User u = service.getUser(name); return u; } @RequestMapping(value='/user3/{name}', produces = MediaType.APPLICATION_JSON_VALUE) public User user3(@PathVariable String name) { User u = userClient.getUser(name); return u; }}

項目結構

先后訪問下面地址，可見到輸出正常結果

http://localhost:9001/user/lchttp://localhost:9001/user2/lc2http://localhost:9001/user3/lc3

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持好吧啦網。