Java发送post方法详解

总结一下java使用http发送post的方法：

1、post请求用于发送json 格式的参数：

/**
  * post请求（用于请求json格式的参数）
  *
  * @param url  地址
  * @param params json格式的参数
  * @return
  */
 public static String doPost(String url, String params) throws Exception {

CloseableHttpClient httpclient = HttpClients.createDefault();
   HttpPost httpPost = new HttpPost( url );// 创建httpPost
   httpPost.setHeader( "Accept", "application/json" );
   httpPost.setHeader( "Content-Type", "application/json" );
   String charSet = "UTF-8";
   StringEntity entity = new StringEntity( params, charSet );
   httpPost.setEntity( entity );
   CloseableHttpResponse response = null;

try {

response = httpclient.execute( httpPost );
     StatusLine status = response.getStatusLine();
     int state = status.getStatusCode();
     if (state == HttpStatus.SC_OK) {
       HttpEntity responseEntity = response.getEntity();
       String jsonString = EntityUtils.toString( responseEntity );
       return jsonString;
     } else {
       logger.error( "请求返回:" + state + "(" + url + ")" );
     }
   } finally {
     if (response != null) {
       try {
         response.close();
       } catch (IOException e) {
         e.printStackTrace();
       }
     }
     try {
       httpclient.close();
     } catch (IOException e) {
       e.printStackTrace();
     }
   }
   return null;
 }

2、用于发送key-value格式的参数

/**
  * post请求(用于key-value格式的参数)
  *
  * @param url
  * @param params
  * @return
  */
 public static String doPost(String url, Map params) {

BufferedReader in = null;
   try {
     // 定义HttpClient
     HttpClient client = new DefaultHttpClient();
     // 实例化HTTP方法
     HttpPost request = new HttpPost();
     request.setURI( new URI( url ) );

//设置参数
     List<NameValuePair> nvps = new ArrayList<NameValuePair>();
     for (Iterator iter = params.keySet().iterator(); iter.hasNext(); ) {
       String name = (String) iter.next();
       String value = String.valueOf( params.get( name ) );
       nvps.add( new BasicNameValuePair( name, value ) );

//System.out.println(name +"-"+value);
     }
     request.setEntity( new UrlEncodedFormEntity( nvps, HTTP.UTF_8 ) );

HttpResponse response = client.execute( request );
     int code = response.getStatusLine().getStatusCode();
     if (code == 200) {  //请求成功
       in = new BufferedReader( new InputStreamReader( response.getEntity()
           .getContent(), "utf-8" ) );
       StringBuffer sb = new StringBuffer( "" );
       String line = "";
       String NL = System.getProperty( "line.separator" );
       while ((line = in.readLine()) != null) {
         sb.append( line + NL );
       }
       in.close();

return sb.toString();
     } else {  //
       System.out.println( "状态码：" + code );
       return null;
     }
   } catch (Exception e) {
     e.printStackTrace();
     return null;
   }
 }

第三，发送get请求

/**
  * get请求
  *
  * @return
  */
 public static String doGet(String url) {
   try {
     HttpClient client = new DefaultHttpClient();
     //发送get请求
     HttpGet request = new HttpGet( url );
     HttpResponse response = client.execute( request );
     /**请求发送成功，并得到响应**/
     if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
       /**读取服务器返回过来的json字符串数据**/
       String strResult = EntityUtils.toString( response.getEntity() );
       return strResult;
     }
   } catch (IOException e) {
     e.printStackTrace();
   }

return null;
 }

以上所述是小编给大家介绍的Java发送post方法详解整合网站的支持！

来源：https://blog.csdn.net/xzj80927/article/details/89098334