public String sendPost_body(String arl, String s) {

// 创建url资源

OutputStreamWriter out = null;

URL url;

BufferedReader in = null;

StringBuilder result = new StringBuilder();

try {

url = new URL(arl);

// 建立http连接

HttpURLConnection conn = (HttpURLConnection) url.openConnection();

// 设置允许输出

conn.setDoOutput(true);

conn.setDoInput(true);

// 设置不用缓存

conn.setUseCaches(false);

// 设置传递方式

conn.setDoOutput(true);

conn.setDoInput(true);

conn.setUseCaches(false);

conn.setInstanceFollowRedirects(true);

conn.setRequestMethod("POST"); // 设置请求方式

conn.setRequestProperty("Accept", "application/json"); // 设置接收数据的格式

conn.setRequestProperty("Content-Type", "application/json"); // 设置发送数据的

conn.setRequestProperty("user-agent",

"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");//设置消息头，解决508错误

// 开始连接请求

conn.connect();

out = new OutputStreamWriter(

conn.getOutputStream(), "UTF-8"); // utf-8编码

// 写入请求的字符串

out.append(s);

out.flush();

out.close();

// System.out.println(conn.getResponseCode());

if(conn.getResponseCode()==200){

// System.out.println("success");

in = new BufferedReader(new InputStreamReader(conn.getInputStream(),"utf-8"));

String line;

while ((line = in.readLine()) != null) {

result.append(line);

}

}

} catch (Exception e) {

//System.out.println("发送 POST 请求出现异常！" + e);

result = new StringBuilder("{\"resCode\":\"1\",\"errCode\":\"1001\",\"resData\":\"\"}");

e.printStackTrace();

//log.error("远程服务未开启", e);

}

finally {

try {

if (out != null) {

out.close();

}

if (in != null) {

in.close();

}

} catch (IOException ex) {

ex.printStackTrace();

}

}

return result.toString();

}

原文：https://www.cnblogs.com/idefault/p/12101849.html