RestTemplate的使用（项目实例）

项目目录

Get请求测试类

package com.example.demo.testRestTemplate;

import com.example.demo.pojo.User;
import org.junit.Test;
import org.springframework.http.*;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestTemplate;

import java.util.HashMap;
import java.util.Map;


/**
 * @author lyd
 * @Description: Get测试
 * @date 10:21
 */
public class TestGet {

	RestTemplate restTemplate = new RestTemplate();

	/**
	 * 简单无参使用
	 */
	@Test
	public void doGetTestOne() {

		String url = "http://localhost:8080/doGetTestOne";

		//方式一：GET 方式获取 JSON 串数据
		String result = restTemplate.getForObject(url, User.class).toString();
		System.out.println("返回结果1：" + result);

		//方式二：GET 方式获取 JSON 数据映射后的 User 实体对象
		User user = restTemplate.getForObject(url, User.class);
		System.out.println("返回结果2：" + user);

		//方式三：GET 方式获取包含 User 实体对象 的响应实体 ResponseEntity 对象,用 getBody() 获取
		ResponseEntity responseEntity = restTemplate.getForEntity(url, User.class);
		System.out.println("返回结果3：" + responseEntity.getBody());

		// 方法四
		//构建请求实体 HttpEntity 对象，用于配置 Header 信息和请求参数
		MultiValueMap header = new LinkedMultiValueMap();//一键多值映射
		header.add(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE);
		HttpEntity<Object> requestEntity = new HttpEntity<>(header);
		//执行请求获取包含 Product 实体对象 的响应实体 ResponseEntity 对象,用 getBody() 获取
		ResponseEntity exchangeResult = restTemplate.exchange(url, HttpMethod.GET, requestEntity, User.class);
		System.out.println("状态值:" + exchangeResult.getStatusCode());
		System.out.println("返回结果4:" + exchangeResult.getBody());

	}

	/**
	 * 复杂使用
	 */
	@Test
	public void doGetTestTwo() {

		String url = "http://localhost:8080/doGetTestWayOne?age={age}";

		//方式一：将参数的值存在可变长度参数里，按照顺序进行参数匹配
		ResponseEntity<User> responseEntity = restTemplate.getForEntity(url, User.class, 27);
		System.out.println("返回结果1:" + responseEntity);

		//方式二：将请求参数以键值对形式存储到 Map 集合中，用于请求时URL上的拼接
		Map<String, Object> uriVariables = new HashMap<>();
		uriVariables.put("age", 101);
		User user = restTemplate.getForObject(url, User.class, uriVariables);
		System.out.println("返回结果2:" + user);
	}


}

Get请求接口

package com.example.demo.controller;

import com.example.demo.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

/**
 * @author lyd
 * @Description: Get对应接收示例
 * @date 10:38
 */
@RestController
public class GetController {

	@Autowired
	User user;

	@RequestMapping("doGetTestOne")
	public Object doGetTestOne() {
		user.setName("getOne");
		user.setMotto("我命油我不油天");
		user.setAge(12);
		user.setGender("男");
		return user;
	}

	@RequestMapping("doGetTestWayOne")
	public Object doGetTestWayOne(Integer age) {
		user.setName("getOne");
		user.setMotto("我命油我不油天");
		user.setAge(age);
		user.setGender("男");
		return user;
	}


}

Post请求测试类

package com.example.demo.testRestTemplate;

import com.example.demo.pojo.User;
import org.junit.Test;
import org.springframework.http.*;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestTemplate;

import java.nio.charset.StandardCharsets;


/**
 * @author lyd
 * @Description: Post请求测试类
 * @date 11:09
 */
public class TestPost {


	RestTemplate restTemplate = new RestTemplate();

	@Test
	public void doPostTestOne() {

		String url = "http://localhost:8080/doPostTestOne";

		// 设置请求的 Content-Type 为 application/x-www-form-urlencoded
		MultiValueMap<String,String> header = new LinkedMultiValueMap<>();
		header.add(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_FORM_URLENCODED_VALUE);

		/**
		 * 方式一拼接： 将请求参数值以 K=V 方式用 & 拼接，发送请求使用
		 */

		// 设置实体类
		User user = new User();
		user.setName("meimei");
		user.setMotto("娇滴滴");
		user.setAge(11);
		user.setGender("女");
		String userStr = "name=" + user.getName() + "&Motto=" + user.getMotto() + "&age=" + user.getAge() + "&Gender=" + user.getGender();
		HttpEntity<String> request = new HttpEntity<>(userStr, header);

		// RestTemplate设定发送UTF-8编码数据
		restTemplate.getMessageConverters().set(1,new StringHttpMessageConverter(StandardCharsets.UTF_8));
		ResponseEntity<User> exchangeResult = restTemplate.exchange(url, HttpMethod.POST, request, User.class);
		System.out.println("返回结果1："+exchangeResult);

		/**
		 * 方式二：将请求参数以键值对形式存储在 MultiValueMap 集合，发送请求时使用
		 */
		MultiValueMap<String,Object> map = new LinkedMultiValueMap();
		map.add("name","titi");
		map.add("age",13);
		map.add("gender","女");
		map.add("motto","猛男");
		HttpEntity<MultiValueMap> request2 = new HttpEntity(map,header);
		// RestTemplate设定发送UTF-8编码数据
		restTemplate.getMessageConverters().set(1,new StringHttpMessageConverter(StandardCharsets.UTF_8));
		ResponseEntity<User> exchangeResult2 = restTemplate.exchange(url,HttpMethod.POST, request2, User.class);
		System.out.println("返回结果2："+exchangeResult2);


	}


}

Post请求接口

package com.example.demo.controller;

import com.example.demo.pojo.User;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author lyd
 * @Description: Post对应返回
 * @date 11:21
 */
@RestController
public class PostController {


   @RequestMapping(value = "doPostTestOne",method = RequestMethod.POST)
   public Object doPostTestOne(User user) {
      return user;
   }


}

文件上传测试类

package com.example.demo.testRestTemplate;

import org.junit.Test;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestTemplate;

import java.io.File;
import java.util.Collections;

/**
 * @author lyd
 * @Description: 上传文件测试类
 * @date 14:17
 */
public class TestFiles {

	RestTemplate restTemplate = new RestTemplate();

	@Test
	public void testUploadFile() {
		String url = "http://localhost:8080/testUploadFile";

		MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
		String filePath = "D:\IdeaProjects\test-RestTemplate\src\main\resources\verifyImg\1.png";
		FileSystemResource fileSystemResource = new FileSystemResource(new File(filePath));
		body.add("file", fileSystemResource);

		MultiValueMap<String,Object> header = new LinkedMultiValueMap<>();
		header.put(HttpHeaders.CONTENT_TYPE, Collections.singletonList(MediaType.MULTIPART_FORM_DATA_VALUE));

		HttpEntity<MultiValueMap<String,Object>> requestEntity = new HttpEntity(body,header);
		ResponseEntity<String> responseEntity = restTemplate.postForEntity(url, requestEntity, String.class);

		System.out.println("upload: " + responseEntity);
	}


}

文件上传请求接口

package com.example.demo.controller;

import com.example.demo.pojo.User;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartRequest;

/**
 * @author lyd
 * @Description: 文件测试类访问接口
 * @date 14:18
 */
@RestController
public class FileController {

	@RequestMapping(value = "testUploadFile",method = RequestMethod.POST)
	public String testUploadFile(MultipartRequest request) {
		// Spring MVC 使用 MultipartRequest 接受带文件的 HTTP 请求
		MultipartFile file = request.getFile("file");
		String originalFilename = file.getOriginalFilename();
		return "upload success filename: " + originalFilename;
	}


}

上面用到的实体类

package com.example.demo.pojo;

import lombok.Data;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.stereotype.Component;

/**
 * @author lyd
 * @Description: 用户实体类
 * @date 11:55
 */
@Data
@Component
public class User {

	private String name;

	private Integer age;

	private String gender;

	private String motto;


}

项目源码

https://github.com/Wranglery/test-RestTemplate