1. 常用依赖

 <!--httpClient Start--><!--httpClient 文件上传 Start--><!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload --><dependency><groupId>commons-fileupload</groupId><artifactId>commons-fileupload</artifactId><version>1.4</version></dependency><!-- https://mvnrepository.com/artifact/commons-io/commons-io --><dependency><groupId>commons-io</groupId><artifactId>commons-io</artifactId><version>2.11.0</version></dependency><!--httpClient 文件上传 End--><!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpcore --><dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpcore</artifactId><version>4.4.14</version></dependency><!-- https://mvnrepository.com/artifact/commons-httpclient/commons-httpclient --><dependency><groupId>commons-httpclient</groupId><artifactId>commons-httpclient</artifactId><version>3.1</version></dependency><!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpmime --><dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpmime</artifactId><version>4.5.13</version></dependency><!--httpClient End-->

2. 工具类

package com.gblfy.utils;import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethodRetryHandler;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.RequestEntity;
import org.apache.commons.httpclient.methods.StringRequestEntity;
import org.apache.commons.httpclient.params.HttpMethodParams;import javax.servlet.http.HttpServletRequest;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Enumeration;/*** Http协议post请求** @author gblfy* @version 1.0* @date 2020-09-28*/
public class HttpApiUtil {/*** 协议类型：HTTP 请求方式：POST 报文格式:json 编码设置：UTF-8 响应类型：jsonStr** @param url     请求地址* @param json    请求报文* @param timeOut 超时时间* @return* @throws Exception*/public static String postJosnContent(String url, String json, int timeOut) throws Exception {System.out.println("请求接口参数：" + json);HttpClient httpClient = new HttpClient();httpClient.getHttpConnectionManager().getParams().setSoTimeout(timeOut);PostMethod method = new PostMethod(url);method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, (HttpMethodRetryHandler) (method1, exception, executionCount) -> false);try {RequestEntity entity = new StringRequestEntity(json, "application/json", "UTF-8");method.setRequestEntity(entity);httpClient.executeMethod(method);System.out.println("请求接口路径url：" + method.getURI().toString());InputStream in = method.getResponseBodyAsStream();// 下面将stream转换为StringStringBuffer sb = new StringBuffer();InputStreamReader isr = new InputStreamReader(in, "UTF-8");char[] b = new char[4096];for (int n; (n = isr.read(b)) != -1; ) {sb.append(new String(b, 0, n));}String returnStr = sb.toString();return returnStr;} catch (Exception e) {e.printStackTrace();throw e;} finally {method.releaseConnection();}}public static String postJosnContent2(HttpServletRequest request, String url, String json, int timeOut) throws Exception {System.out.println("请求接口参数：" + json);HttpClient httpClient = new HttpClient();httpClient.getHttpConnectionManager().getParams().setSoTimeout(timeOut);PostMethod method = new PostMethod(url);method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, (HttpMethodRetryHandler) (method1, exception, executionCount) -> false);try {RequestEntity entity = new StringRequestEntity(json, "application/json", "UTF-8");method.setRequestEntity(entity);// 如果存在多个header的建议参数传递map，编译map添加header，下面二种添加header的场景情况//TODO 1 添加自定义header （不需要特殊处理）method.addRequestHeader("自定义header key", "自定义header value");//TODO 2 添加header 需要特殊处理for (Enumeration<String> e = request.getHeaderNames(); e.hasMoreElements(); ) {String name = e.nextElement().toString();System.out.println(name + ":" + request.getHeader(name));if ("Content-Type".equalsIgnoreCase(name)) {method.addRequestHeader(name, request.getHeader(name));}if ("appid".equalsIgnoreCase(name)) {method.addRequestHeader(name, request.getHeader(name));}if ("appsecret".equalsIgnoreCase(name)) {method.addRequestHeader(name, request.getHeader(name));}}httpClient.executeMethod(method);System.out.println("请求接口路径url：" + method.getURI().toString());InputStream in = method.getResponseBodyAsStream();// 下面将stream转换为StringStringBuffer sb = new StringBuffer();InputStreamReader isr = new InputStreamReader(in, "UTF-8");char[] b = new char[4096];for (int n; (n = isr.read(b)) != -1; ) {sb.append(new String(b, 0, n));}String returnStr = sb.toString();return returnStr;} catch (Exception e) {e.printStackTrace();throw e;} finally {method.releaseConnection();}}// -------------------------------------------单元测试---------------------------------------
//	public static void main(String[] args) throws Exception {
//
//		// 客户端发送String url = "http://127.0.0.1:8080postToJson";String json = "{\"name\":\"gblfy\"}";
//		 String res = postJosnContent(url, json,5000);
//		 System.out.println("响应报文:" + res);
//
//		// 服务端接收
//		// @RequestMapping(value = "/postToJson", method = RequestMethod.POST,produces =
//		// "application/json;charset=UTF-8")
//		// @ResponseBody
//		// public String postToJson(@RequestBody String json) {
//		// System.out.println(json);
//		// return json;
//	}}