httpclient 发送一个请求

httpclient版本 4.1

发送一个post请求

    public static JSONObject post(String url,JSONObject json){
            HttpClient client = new DefaultHttpClient();
            HttpPost post = new HttpPost(url);
            JSONObject response = null;
            try {
                StringEntity s = new StringEntity(json.toString());
                s.setContentEncoding("UTF-8");
                s.setContentType("application/json");
                post.setEntity(s);  

                 HttpResponse res = client.execute(post);
                 if(res.getStatusLine().getStatusCode() == HttpStatus.OK.value()){
                     HttpEntity entity = res.getEntity();
                     String charset = EntityUtils.getContentCharSet(entity);
                     response = new JSONObject(new JSONTokener(new InputStreamReader(entity.getContent(),charset)));
                 }
             } catch (Exception e) {
                 throw new RuntimeException(e);
             }
             return response;
         }  

模拟提交form：

    private static HttpPost postForm(String url, Map<String, String> params){  

        HttpPost httpost = new HttpPost(url);
        List<NameValuePair> nvps = new ArrayList <NameValuePair>();  

        Set<String> keySet = params.keySet();
        for(String key : keySet) {
            nvps.add(new BasicNameValuePair(key, params.get(key)));
        }  

         try {
             log.info("set utf-8 form entity to httppost");
             httpost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));
         } catch (UnsupportedEncodingException e) {
             e.printStackTrace();
         }  

         return httpost;
     }  

get请求

    public static String get(String url) {
           DefaultHttpClient httpclient = new DefaultHttpClient();
           String body = null;  

           log.info("create httppost:" + url);
           HttpGet get = new HttpGet(url);
           body = invoke(httpclient, get);  

           httpclient.getConnectionManager().shutdown();  

            return body;
        }

发起一个post请求，设置超时：

需要注意各个版本设置超时的api都不相同。

还有需要注意的是3中超时：

1，连接超时：connectionTimeout 指的是连接一个url的连接等待时间。

2，读取数据超时：soTimeout  指的是连接上一个url，获取response的返回等待时间

3，SocketTimeout ：定义了Socket读数据的超时时间，即从服务器获取响应数据需要等待的时间

    public static String sendPostRequest(String url, String str, String contentType, String charset){
//        HttpParams httpParams = new BasicHttpParams();//4.1版本
//        HttpConnectionParams.setConnectionTimeout(httpParams, 5000);//建立连接超时时间，防止调用url为死链，消耗服务器io
//        HttpConnectionParams.setSoTimeout(httpParams, 3000);// 响应超时
//        CloseableHttpClient httpClient = new DefaultHttpClient();
        RequestConfig.Builder requestBuilder = RequestConfig.custom();//4.3.5版本
        requestBuilder = requestBuilder.setConnectTimeout(5000);
        //requestBuilder = requestBuilder.setConnectionRequestTimeout(100);

        HttpClientBuilder builder = HttpClientBuilder.create();
        builder.setDefaultRequestConfig(requestBuilder.build());
        CloseableHttpClient httpClient = builder.build();

        HttpPost post = new HttpPost(url);
        //RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(2000).setConnectTimeout(2000).build();
        //post.setConfig(requestConfig);
        post.setHeader("Content-Type", contentType);
        ResponseHandler<String> responseHandler = new BasicResponseHandler();
        String response = null;
        try {
            post.setEntity(new StringEntity(str, charset));
            long start = System.currentTimeMillis();
            try {
                response = httpClient.execute(post,responseHandler);
            } catch (Exception ConnectionTimeoutException) {//建立连接超时异常
                long p = System.currentTimeMillis() - start;
                log.error("sendPostRequest has a ConnectionTimeoutException timeout=> "+ p +"  "+ url);
            }finally{
                //httpClient.getConnectionManager().shutdown();
                post.releaseConnection();
            }
        } catch (Exception e) {
            log.error("执行HTTP Post请求" + url + "时，发生异常！", e);
        }
        return response;
    }