Spring Boot2釋出呼叫REST服務實現方法
阿新 • • 發佈：2020-04-26
開發環境：IntelliJ IDEA 2019.2.2
Spring Boot版本：2.1.8
一、釋出REST服務
1、IDEA新建一個名稱為rest-server的Spring Boot專案
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;
@RestController
public 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;
}
}專案結構如下：
訪問http://localhost:8080/user/lc，頁面顯示：
{"name":"lc","age":30}
二、使用RestTemplae呼叫服務
1、IDEA新建一個名稱為rest-client的Spring Boot專案
2、新建一個含有main方法的普通類RestTemplateMain.java，呼叫服務
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()'，控制檯輸出：lc,30
3、在bean裡面使用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;
@Service
public 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 中呼叫
配置在application.properties 配置埠和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呼叫服務
繼續在rest-client專案基礎上修改程式碼。
1、pom.xml新增依賴
<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、新建介面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 中呼叫
decoder(new GsonDecoder()) 表示添加了解碼器的配置，GsonDecoder會將返回的JSON字串轉換為介面方法返回的物件。
相反的，encoder(new GsonEncoder())則是編碼器，將物件轉換為JSON字串。
@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步程式碼，並把請求地址放到配置檔案中。
（1）application.properties 新增配置
複製程式碼 程式碼如下: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;
@Configuration
public 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 中呼叫
@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;
@RestController
public 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}","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;
}
}
專案結構
先後訪問下面地址，可見到輸出正常結果
http://localhost:9001/user/lc
http://localhost:9001/user2/lc2
http://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，也希望大家多多支援我們。