用java向web站点发送post请求。

Question

conn = (HttpURLConnection) target.openConnection();
conn.setDoInput(true); 
conn.setDoOutput(true);
conn.setUseCaches(false);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
conn.setRequestProperty("Connection", "Keep-Alive");
dataOutStream = new DataOutputStream(conn.getOutputStream());
dataOutStream.writeBytes("username=bob&password=232");
dataOutStream.flush();
dataOutStream.close();

Answer 1

我这么写的。 服务器端
System.out.println("doPost!@!!!!!!!!!!!!!!!!!!!!!");
response.setContentType("text/html; charset=UTF-8");
response.setHeader("Cache-Control", "no-cache");

try {
System.out.println(request.getContentType().toString()
+ "---getContentType");
System.out.println(request.getParameter("username") + "---getParameter");
的不到这个username的值，取得是null

Answer 2

你set"username"这个属性值了么?比如http://localhost:8080/aa/aaa.jsp?username="liuyun",在request作用范围内有这个键值才能取的到啊

Answer 3

同意duncan301的,没发现你什么地方给username赋值

Answer 4

dataOutStream.writeBytes("username=bob&password=232"); 这个位置给username负值了 username=bob 
问题解决了。

Answer 5

未发现错误
conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");可以不设置