Java发送post方法

不念不忘少年蓝@ 2022-04-23 18:34 676阅读 0赞

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;
        }