今天想实现 java 后端发送 formdata 上传文件，为了以后查找方便，特此记录下来
上一次使用 WebClient 实现远程调用 （一个非阻塞、响应式的HTTP客户端，它以响应式被压流的方式执行HTTP请求） 查看
现在使用的 RestTemplate
RestTemplate 是在客户端访问 Restful 服务的一个核心类
默认使用 JDK 提供的包去建立HTTP连接
为每种 HTTP 请求都实现了相关的请求封装方法
public <T> T postForObject(URI url, @Nullable Object request, Class<T> responseType)
url -> URI类型的请求路径
request -> 请求体对象
responseType -> 响应数据类型
package com.example.hystrix.controller; import org.springframework.core.io.FileSystemResource; import org.springframework.util.LinkedMultiValueMap; import org.springframework.util.MultiValueMap; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.client.RestTemplate; import java.io.File; @RestController public class DemoController { @RequestMapping("/upload") public String upload() { String url = "http://localhost:2001/api/upload"; //上传的地址 String filePath = "E:\\test\\test.dxf"; RestTemplate rest = new RestTemplate(); FileSystemResource resource = new FileSystemResource(new File(filePath)); MultiValueMap<String, Object> param = new LinkedMultiValueMap<>(); param.add("files", resource); //MultipartFile的名称 String rs = rest.postForObject(url, param, String.class); System.out.println(rs); return rs; } }
或者
public <T> ResponseEntity<T> exchange(URI url, HttpMethod method, @Nullable HttpEntity<?> requestEntity, Class<T> responseType)
url -> URI类型的请求路径
method-> 请求方式
requestEntity-> 请求体
responseType -> 响应数据类型
package com.example.hystrix.controller; import org.springframework.core.io.FileSystemResource; import org.springframework.http.HttpEntity; import org.springframework.http.HttpMethod; import org.springframework.http.ResponseEntity; import org.springframework.util.LinkedMultiValueMap; import org.springframework.util.MultiValueMap; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.client.RestTemplate; import java.io.File; @RestController public class DemoController { @RequestMapping("/upload") public String upload() { String url = "http://localhost:2001/api/upload"; //上传的地址 String filePath = "E:\\test\\test.dxf"; RestTemplate rest = new RestTemplate(); FileSystemResource resource = new FileSystemResource(new File(filePath)); MultiValueMap<String, Object> param = new LinkedMultiValueMap<>(); param.add("files", resource); //MultipartFile的名称 HttpEntity<MultiValueMap<String, Object>> httpEntity = new HttpEntity<MultiValueMap<String, Object>>(param); ResponseEntity<String> responseEntity = rest.exchange(url, HttpMethod.POST, httpEntity, String.class); String rs = responseEntity.getBody(); System.out.println(rs); return rs; } }
原文：https://www.cnblogs.com/baby123/p/12174942.html