Java 发送Http get/post请求

本篇文章主要通过以下俩种包实现get/post请求方法！

1. java.net.URL
2. org.apache.http.client

URL包实现

当前实现所需要的URL是在package java.net包下，点击查看源码，由此可知，此包是JDK自带的包！使用URL发送Http请求使用的是最原始方法发送！

POST请求

废话不多说，直接上代码，如下所示：

/**
     * 向指定 URL 发送POST方法的请求
     *
     * @param url
     *            发送请求的 URL  (可以将参数丢url后面传过去URL?productCode=YUNPHMIP)
     * @param param
     *            请求参数，请求参数应该是json的形式。
     * @return 所代表远程资源的响应结果
     */
    public String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 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)");
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 设置编码格式
            conn.setRequestProperty("Charset","UTF-8");
            conn.setRequestProperty("Content-type", "application/json;charset=UTF-8");
            // 获取URLConnection对象对应的输出流
             out = new PrintWriter(conn.getOutputStream());
            // 发送请求参数
             out.print(param);
            // 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()));

            String line;
            while ((line = in.readLine()) != null) {
                line = new String(line.getBytes(), "utf-8");
                result += 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;
    }

若发送过程中存在乱码，解决办法如下所示：

       // 获取URLConnection对象对应的输出流
      OutputStream os = conn.getOutputStream();
      OutputStreamWriter ow = new OutputStreamWriter(os, "UTF-8");
      out = new PrintWriter(ow);
      // 发送请求参数
      out.print(param);
      // flush输出流的缓冲
      out.flush();

GET请求

具体代码如下所示：

/**
     * 向指定URL发送GET方法的请求
     *
     * @param url
     *   发送请求的URL
     * @param param
     *   请求参数，请求参数应该是 name=value&name1=value1 的形式。
     * @return URL 所代表远程资源的响应结果
     */
    public static String sendGet(String url, String param) {
        String result = "";
        BufferedReader in = null;
        try {
            String urlNameString = url + "?" + param;
            URL realUrl = new URL(urlNameString);
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 建立实际的连接
            connection.connect();
            // 获取所有响应头字段
            // Map<String, List<String>> map = connection.getHeaderFields();
            // 定义 BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 使用finally块来关闭输入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return result;
    }

httpclient包实现

使用此方法实现需要引入pom文件，具体引入文件如下所示：

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpcore -->
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore</artifactId>
    <version>4.4.8</version>
</dependency>

POST请求

具体代码如下所示：

	private static CloseableHttpClient httpClient = HttpClientBuilder.create().build();

   /**
     * get请求
     * @param url
     * @return
     */
    public static String get(String url) {
        CloseableHttpResponse response = null;
        BufferedReader in = null;
        String result = "";
        try {
            HttpGet httpGet = new HttpGet(url);
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(3000).setConnectionRequestTimeout(3000).setSocketTimeout(3000).build();
            httpGet.setConfig(requestConfig);
            httpGet.setConfig(requestConfig);
            httpGet.addHeader("Content-type", "application/json; charset=utf-8");
            httpGet.setHeader("Accept", "application/json");
            response = httpClient.execute(httpGet);
            in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            StringBuffer sb = new StringBuffer("");
            String line = "";
            String NL = System.getProperty("line.separator");
            while ((line = in.readLine()) != null) {
                sb.append(line + NL);
            }
            in.close();
            result = sb.toString();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != response) {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

GET请求

具体代码如下所示：

	private static CloseableHttpClient httpClient = HttpClientBuilder.create().build();

   /**
     * post请求
     * @param url
     * @param jsonString
     * @return
     */
    public static String post(String url, String jsonString) {
        CloseableHttpResponse response = null;
        BufferedReader in = null;
        String result = "";
        try {
            HttpPost httpPost = new HttpPost(url);
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(30000).setConnectionRequestTimeout(30000).setSocketTimeout(30000).build();
            httpPost.setConfig(requestConfig);
            httpPost.setConfig(requestConfig);
            httpPost.addHeader("Content-type", "application/json; charset=utf-8");
            httpPost.setHeader("Accept", "application/json");
            httpPost.setEntity(new StringEntity(jsonString, Charset.forName("UTF-8")));
            response =  httpClient.execute(httpPost);
            in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            StringBuffer sb = new StringBuffer("");
            String line = "";
            String NL = System.getProperty("line.separator");
            while ((line = in.readLine()) != null) {
                sb.append(line + NL);
            }
            in.close();
            result = sb.toString();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != response) {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

以上就是俩种不同包的连接方法！若有不足之处，请您指正！

标题java调用HTTP接口（Get请求和Post请求）

package com.example.controller;

import com.alibaba.fastjson.JSONObject;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

public class testMain {
    public static void main(String[] args) {
        String a = sendPost("http://localhost:8022/girl","{'name':'xiaohong','title':'heihei'}");//post 415可能是请求头的问题400可能是传的参数格式
        interfaceUtil("http://localhost:8022/girl?name=xiaohong&title=heihei","");//get
        System.out.println(a);
    }
    public static String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setRequestMethod("POST");
            conn.setUseCaches(false);
            conn.setInstanceFollowRedirects(true);
            // 设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("Content-Type","application/json;charset=utf-8");
            conn.connect();

            OutputStreamWriter outputStreamWriter =
                    new OutputStreamWriter(conn.getOutputStream(),"utf-8");
            out = new PrintWriter(outputStreamWriter);
            //转化json格式字符串
            JSONObject jsonObject = JSONObject.parseObject(param);
            out.print(jsonObject);
            // flush输出流的缓冲
            out.flush();
            out.close();
            //查看状态码
            int responseCode = conn.getResponseCode();
            // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送 POST 请求出现异常！"+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;
    }

    /**
     * 调用对方接口方法
     * @param path 对方或第三方提供的路径
     * @param data 向对方或第三方发送的数据，大多数情况下给对方发送JSON数据让对方解析
     */
    public static void interfaceUtil(String path,String data) {
        try {
            URL url = new URL(path);
            //打开和url之间的连接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            PrintWriter out = null;

            /**设置URLConnection的参数和普通的请求属性****start***/

            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");

            /**设置URLConnection的参数和普通的请求属性****end***/

            //设置是否向httpUrlConnection输出，设置是否从httpUrlConnection读入，此外发送post请求必须设置这两个
            //最常用的Http请求无非是get和post，get请求可以获取静态页面，也可以把参数放在URL字串后面，传递给servlet，
            //post与get的 不同之处在于post的参数不是放在URL字串里面，而是放在http请求的正文内。
            conn.setDoOutput(true);
            conn.setDoInput(true);

            conn.setRequestMethod("GET");//GET和POST必须全大写
            /**GET方法请求*****start*/
            /**
             * 如果只是发送GET方式请求，使用connet方法建立和远程资源之间的实际连接即可；
             * 如果发送POST方式的请求，需要获取URLConnection实例对应的输出流来发送请求参数。
             * */
            conn.connect();

            /**GET方法请求*****end*/

            /***POST方法请求****start*/

            /*out = new PrintWriter(conn.getOutputStream());//获取URLConnection对象对应的输出流

            out.print(data);//发送请求参数即数据

            out.flush();//缓冲数据
            */
            /***POST方法请求****end*/

            //获取URLConnection对象对应的输入流
            InputStream is = conn.getInputStream();
            //构造一个字符流缓存
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            String str = "";
            while ((str = br.readLine()) != null) {
                str=new String(str.getBytes(),"UTF-8");//解决中文乱码问题
                System.out.println(str);
            }
            //关闭流
            is.close();
            //断开连接，最好写上，disconnect是在底层tcp socket链接空闲时才切断。如果正在被其他线程使用就不切断。
            //固定多线程的话，如果不disconnect，链接会增多，直到收发不出信息。写上disconnect后正常一些。
            conn.disconnect();
            System.out.println("完整结束");
        } catch (Exception e) {
            e.printStackTrace();
        }

}

1.示例

• get请求，参数可以拼接在url上
• post请求，参数使用json字符串

<dependency>
  <groupId>org.apache.httpcomponents</groupId>
  <artifactId>httpclient</artifactId>
  <version>4.5.10</version>
</dependency>
<dependency>
  <groupId>commons-httpclient</groupId>
  <artifactId>commons-httpclient</artifactId>
  <version>3.1</version>
</dependency>

package org.example;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ByteArrayEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.CharArrayBuffer;
import org.apache.http.util.EntityUtils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.util.stream.Collectors;

public class TTest {
	//get
    public static String getHttp(String url) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL urls = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) urls.openConnection();
            conn.setRequestMethod("GET");
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setReadTimeout(10000);
            conn.setConnectTimeout(10000);
            out = new PrintWriter(conn.getOutputStream());
            out.flush();
            in = new BufferedReader(new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8));
            result = in.lines().collect(Collectors.joining());
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        return result;
    }
    //get
    public static String getJson(String url) {
        String result = null;
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpGet post = new HttpGet(url);
        CloseableHttpResponse response = null;
        try {
            post.setHeader("Content-Type", "application/json");
            response = httpClient.execute(post);
            if (response != null && response.getStatusLine().getStatusCode() == 200) {
                HttpEntity entity = response.getEntity();
                result = entityToString(entity);
            }
            return result;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
                if (response != null) {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }
    //post
    public static String postJson(String url, String jsonString) {
        String result = null;
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost post = new HttpPost(url);
        CloseableHttpResponse response = null;
        try {
            post.setHeader("Content-Type", "application/json");
            if (null != jsonString) {
                post.setEntity(new ByteArrayEntity(jsonString.getBytes(StandardCharsets.UTF_8)));
            }
            response = httpClient.execute(post);
            if (response != null && response.getStatusLine().getStatusCode() == 200) {
                HttpEntity entity = response.getEntity();
                result = entityToString(entity);
            }
            return result;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
                if (response != null) {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    public static String entityToString(HttpEntity entity) throws IOException {
        String result = null;
        if (entity != null) {
            long length = entity.getContentLength();
            if (length != -1 && length < 2048) {
                result = EntityUtils.toString(entity, "UTF-8");
            } else {
                try (InputStreamReader reader1 = new InputStreamReader(entity.getContent(), StandardCharsets.UTF_8)) {
                    CharArrayBuffer buffer = new CharArrayBuffer(2048);
                    char[] tmp = new char[1024];
                    int l;
                    while ((l = reader1.read(tmp)) != -1) {
                        buffer.append(tmp, 0, l);
                    }
                    result = buffer.toString();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return result;
    }

    //POST请求以application/x-www-form-urlencoded;charset=utf-8格式
    public static String postForm(String postURL,String name,String age){
        PostMethod postMethod = new PostMethod(postURL) ;
        postMethod.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=utf-8") ;
        //参数设置，需要注意的就是里边不能传NULL，要传空字符串
        NameValuePair[] data = {
                new NameValuePair("name",name),
                new NameValuePair("age",age)
        };
        postMethod.setRequestBody(data);
        HttpClient httpClient = new HttpClient();
        String result = null;
        try {
            httpClient.executeMethod(postMethod);
            result = postMethod.getResponseBodyAsString();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }
    public static void main(String[] args) {
        System.out.println(getHttp("https://www.baidu.com"));
        System.out.println("--------------------------------华丽的分割线-----------------------------------");
        System.out.println(postJson("https://www.baidu.com", null));
        System.out.println("--------------------------------华丽的分割线-----------------------------------");
        System.out.println(postForm("https://www.baidu.com", null, null));
    }
}

2.打印

<!DOCTYPE html><!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=https://ss1.bdstatic.com/5eN1bjq8AAUYm2zgoY3K/r/www/cache/bdorz/baidu.min.css><title>百度一下，你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> </div> <form id=form name=f action=//www.baidu.com/s class=fm> <input type=hidden name=bdorz_come value=1> <input type=hidden name=ie value=utf-8> <input type=hidden name=f value=8> <input type=hidden name=rsv_bp value=1> <input type=hidden name=rsv_idx value=1> <input type=hidden name=tn value=baidu><span class="bg s_ipt_wr"><input id=kw name=wd class=s_ipt value maxlength=255 autocomplete=off autofocus=autofocus></span><span class="bg s_btn_wr"><input type=submit id=su value=百度一下 class="bg s_btn" autofocus></span> </form> </div> </div> <div id=u1> <a href=http://news.baidu.com name=tj_trnews class=mnav>新闻</a> <a href=https://www.hao123.com name=tj_trhao123 class=mnav>hao123</a> <a href=http://map.baidu.com name=tj_trmap class=mnav>地图</a> <a href=http://v.baidu.com name=tj_trvideo class=mnav>视频</a> <a href=http://tieba.baidu.com name=tj_trtieba class=mnav>贴吧</a> <noscript> <a href=http://www.baidu.com/bdorz/login.gif?login&amp;tpl=mn&amp;u=http%3A%2F%2Fwww.baidu.com%2f%3fbdorz_come%3d1 name=tj_login class=lb>登录</a> </noscript> <script>document.write('<a href="http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u='+ encodeURIComponent(window.location.href+ (window.location.search === "" ? "?" : "&")+ "bdorz_come=1")+ '" name="tj_login" class="lb">登录</a>');                </script> <a href=//www.baidu.com/more/ name=tj_briicon class=bri style="display: block;">更多产品</a> </div> </div> </div> <div id=ftCon> <div id=ftConw> <p id=lh> <a href=http://home.baidu.com>关于百度</a> <a href=http://ir.baidu.com>About Baidu</a> </p> <p id=cp>&copy;2017&nbsp;Baidu&nbsp;<a href=http://www.baidu.com/duty/>使用百度前必读</a>&nbsp; <a href=http://jianyi.baidu.com/ class=cp-feedback>意见反馈</a>&nbsp;京ICP证030173号&nbsp; <img src=//www.baidu.com/img/gs.gif> </p> </div> </div> </div> </body> </html>
--------------------------------华丽的分割线-----------------------------------
<!DOCTYPE html>
<!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=https://ss1.bdstatic.com/5eN1bjq8AAUYm2zgoY3K/r/www/cache/bdorz/baidu.min.css><title>百度一下，你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> </div> <form id=form name=f action=//www.baidu.com/s class=fm> <input type=hidden name=bdorz_come value=1> <input type=hidden name=ie value=utf-8> <input type=hidden name=f value=8> <input type=hidden name=rsv_bp value=1> <input type=hidden name=rsv_idx value=1> <input type=hidden name=tn value=baidu><span class="bg s_ipt_wr"><input id=kw name=wd class=s_ipt value maxlength=255 autocomplete=off autofocus=autofocus></span><span class="bg s_btn_wr"><input type=submit id=su value=百度一下 class="bg s_btn" autofocus></span> </form> </div> </div> <div id=u1> <a href=http://news.baidu.com name=tj_trnews class=mnav>新闻</a> <a href=https://www.hao123.com name=tj_trhao123 class=mnav>hao123</a> <a href=http://map.baidu.com name=tj_trmap class=mnav>地图</a> <a href=http://v.baidu.com name=tj_trvideo class=mnav>视频</a> <a href=http://tieba.baidu.com name=tj_trtieba class=mnav>贴吧</a> <noscript> <a href=http://www.baidu.com/bdorz/login.gif?login&amp;tpl=mn&amp;u=http%3A%2F%2Fwww.baidu.com%2f%3fbdorz_come%3d1 name=tj_login class=lb>登录</a> </noscript> <script>document.write('<a href="http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u='+ encodeURIComponent(window.location.href+ (window.location.search === "" ? "?" : "&")+ "bdorz_come=1")+ '" name="tj_login" class="lb">登录</a>');
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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 java.io.IOException;
import java.util.*;

public class TTest {

    //post params
    public static String postParams(String url, Map<String, String> params, Map<String, String> header) {
        String result = null;
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost request = new HttpPost(url);
        CloseableHttpResponse response;
        try {
            if (params != null) {
                UrlEncodedFormEntity uefEntity = new UrlEncodedFormEntity(addParams(params), "UTF-8");
                request.setEntity(uefEntity);
            }
            addHeader(header, request);
            response = httpClient.execute(request);
            if (response == null) {
                return null;
            }
            result = EntityUtils.toString(response.getEntity(), "UTF-8");
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }

    private static List<BasicNameValuePair> addParams(Map<String, String> map) {
        List<BasicNameValuePair> formParams = new ArrayList<>();
        if (map != null) {
            Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
            while (it.hasNext()) {
                Map.Entry<String, String> entry = it.next();
                formParams.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
            }
        }
        return formParams;
    }

    private static void addHeader(Map<String, String> map, HttpPost post) {
        if (map != null) {
            Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
            while (it.hasNext()) {
                Map.Entry<String, String> entry = it.next();
                post.setHeader(entry.getKey(), entry.getValue());
            }
        }
    }

    public static void main(String[] args) {
        String url = "https://www.baidu.com";
        Map<String, String> para = new HashMap<>();
        Map<String, String> header = new HashMap<>();
        String s = postParams(url, para, header);
        System.out.println(s);
    }

}