简单的Http请求工具类Demo

第一个版本（含字符串数组）：

相关依赖：

        <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
		<dependency>
		    <groupId>org.apache.httpcomponents</groupId>
		    <artifactId>httpclient</artifactId>
		</dependency>
		
		<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
		<dependency>
		    <groupId>com.alibaba</groupId>
		    <artifactId>fastjson</artifactId>
		    <version>1.2.56</version>
		</dependency>

发送方：

package com.tm.demo.test;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import com.alibaba.fastjson.JSONObject;


/**
 * @Classname HttpTest
 * @Description TODO 测试http请求工具类
 * @Date 2019/7/3 0003 16:24
 * @Created by jtj
 */

public class HttpTest {

	public static void main(String[] args) throws Exception {
		Map<String,String> map = new HashMap<>();
		//参数是字符串类型
		map.put("msgType", "0"); //消息类型
		map.put("cmdId","1");  //指令标识	
		//参数有数组，转成json字符串
		Map<String,String[]> cmdParams = new HashMap<>();
		cmdParams.put("dev", new String[]{"1","2","3"});
		map.put("cmdParams",JSONObject.toJSONString(cmdParams)); //指令参数
		//发送请求
		String result = postMethod("http://localhost:8080/test", map);
		System.out.println("返回结果:"+result);
	}
	
	/**
	 * @param url 请求地址
	 * @param params  参数
	 * @return  结果
	 * @throws Exception
	 */
	public static String postMethod(String url, Map<String, String> params) throws Exception {

		CloseableHttpClient client = HttpClients.createDefault();
		CloseableHttpResponse response = null;

		RequestConfig config = RequestConfig.custom().setConnectTimeout(20000).setSocketTimeout(20000).build();
		HttpPost httpPost = new HttpPost(url);
		httpPost.setConfig(config);

		List<NameValuePair> list = new ArrayList<NameValuePair>();

		Set<String> keySets = params.keySet();
		for (String key : keySets) {

			String value = params.get(key);
			list.add(new BasicNameValuePair(key, value));
		}

		try {
			httpPost.setEntity(new UrlEncodedFormEntity(list));
			response = client.execute(httpPost);
			HttpEntity entity = response.getEntity();
			String content = EntityUtils.toString(entity);

			return content;

		} catch (Exception e) {

			throw e;
		} finally {

			httpPost.releaseConnection();
			response.close();

		}

	}
}

 接收方：

    @RequestMapping("/test")
    @ResponseBody
    public String test(HttpServletRequest request){
        Map<String,String[]> params = request.getParameterMap();
        Iterator entries = params.entrySet().iterator();
        while (entries.hasNext()) {
            Map.Entry<String, String[]> entry = (Map.Entry<String, String[]>)entries.next();
            //获取key值
            System.out.println("Key = " + entry.getKey());
            //这里的value值为数组形式,暂时用字符串代替，按自己需要去组织
            System.out.println("Value = " + JSONObject.toJSONString(entry.getValue()));
        }
        return "copy";
    }

第二版本（不含字符串数组）： 

package com.swft.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;

/** 
 * @ClassName: HttpObject
 * @description: 
 * @author: JTJ
 * @Date: 2019年2月18日 下午5:49:55
 */

public class HttpObject {
	
	/**
	 * @Title: sendPost 
	 * @Desc: 向指定url发送post请求 
	 * @param url 指定url地址
	 * @param params 请求参数
	 * @return 远程资源的响应结果
	 */
	public String sendPost(String url, Map<String, String> params) {
		OutputStreamWriter out = null;
        BufferedReader in = null;        
        StringBuilder result = new StringBuilder();
        try {
            URL realUrl = new URL(url);
            HttpURLConnection conn =(HttpURLConnection) realUrl.openConnection();
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // POST方法
            conn.setRequestMethod("POST");
            // 设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            conn.connect();
            // 获取URLConnection对象对应的输出流
            out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            // 发送请求参数            
            if (params != null) {
		          StringBuilder param = new StringBuilder(); 
		          for (Map.Entry<String, String> entry : params.entrySet()) {
		        	  if(param.length()>0){
		        		  param.append("&");
		        	  }	        	  
		        	  param.append(entry.getKey());
		        	  param.append("=");
		        	  param.append(entry.getValue());		        	  
		        	  //System.out.println(entry.getKey()+":"+entry.getValue());
		          }
		          //System.out.println("param:"+param.toString());
		          out.write(param.toString());
            }
            // flush输出流的缓冲
            out.flush();
            // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream(), "UTF-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
        } catch (Exception e) {            
            e.printStackTrace();
        }
        //使用finally块来关闭输出流、输入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
		return result.toString();		
	}
}