通过post请求获得服务端返回的数据

之前做项目的时候遇到的问题，现已解决，上传上来留个记录方便以后回顾。

 1 import java.io.BufferedReader;
 2 import java.io.InputStreamReader;
 3 import java.io.OutputStream;
 4 import java.net.HttpURLConnection;
 5 import java.net.URL;
 6 
 7 public static String post(String json, String url) {
 8         String line = null;
 9         try {
10             URL url1 = new URL(url);
11             HttpURLConnection conn = (HttpURLConnection) url1.openConnection();
12             conn.setDoOutput(true);
13             conn.setDoInput(true);
14             // 设置不用缓存
15             conn.setUseCaches(false);
16             // 设置传递方式
17             conn.setRequestMethod("POST");
18             // 设置维持长连接
19             conn.setRequestProperty("Connection", "Keep-Alive");
20             // 设置文件字符集:
21             conn.setRequestProperty("Charset", "UTF-8");
22             // 转换为字节数组
23             byte[] data = (json.getBytes());
24             // 设置文件长度
25             conn.setRequestProperty("Content-Length", String.valueOf(data.length));
26             // 设置文件类型:
27             conn.setRequestProperty("Content-Type", "application/json");
28             // 开始连接请求
29             conn.connect();
30             OutputStream out = conn.getOutputStream();
31             // 写入请求的字符串
32             out.write(json.getBytes());
33             out.flush();
34             out.close();
35             // 请求返回的状态
36             if (conn.getResponseCode() == 200) {
37                 // 请求返回的数据
38                 BufferedReader in = null;
39                 in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
40                 line = in.readLine();
41             }
42         } catch (Exception e) {
43         }
44         return line;
45     }