我有代码对Web表单执行POST，然后读取内容。我有两个问题 - 1）在POST数据后我不需要读取响应 - 我只需要url。所以我不需要readResponse方法，但是当我删除它时程序不起作用; 2）发布后，有一个重定向到另一个页面。当我打印出URL时，我得到的第一个URL而不是我正在寻找的最终重定向的URL。
基本上，我想要的类会将数据发布到页面而不读取响应，而是在重定向后获取页面的URL。任何帮助是极大的赞赏。谢谢！
import java.net.*;
import java.io.*;
public class LoginByHttpPost
{
private static final String POST_CONTENT_TYPE = "application/x-www-form-urlencoded";
private static final String LOGIN_USER_NAME = "oipsl";
private static final String TARGET_URL = "http://www.clubspeedtiming.com/prkapolei/login.aspx";
public static void main (String args[])
{
LoginByHttpPost httpUrlBasicAuthentication = new LoginByHttpPost();
httpUrlBasicAuthentication.httpPostLogin();
}
/**
* The single public method of this class that
* 1. Prepares a login message
* 2. Makes the HTTP POST to the target URL
* 3. Reads and returns the response
*
* @throws IOException
* Any problems while doing the above.
*
*/
public void httpPostLogin ()
{
try
{
// Prepare the content to be written
// throws UnsupportedEncodingException
String urlEncodedContent = preparePostContent(LOGIN_USER_NAME);
HttpURLConnection urlConnection = doHttpPost(TARGET_URL, urlEncodedContent);
urlConnection.setFollowRedirects(true);
System.out.println(urlConnection.getResponseCode());
System.out.println(urlConnection.getHeaderFields());
String response = readResponse(urlConnection);
System.out.println("Successfully made the HTPP POST.");
System.out.println("Received response is: " + response);
}
catch(IOException ioException)
{
System.out.println("Problems encountered.");
}
}
/**
* Using the given username and password, and using the static string variables, prepare
* the login message. Note that the username and password will encoded to the
* UTF-8 standard.
*
* @param loginUserName
* The user name for login
*
* @param loginPassword
* The password for login
*
* @return
* The complete login message that can be HTTP Posted
*
* @throws UnsupportedEncodingException
* Any problems during URL encoding
*/
private String preparePostContent(String loginUserName) throws UnsupportedEncodingException
{
// Encode the user name and password to UTF-8 encoding standard
// throws UnsupportedEncodingException
String encodedLoginUserName = URLEncoder.encode(loginUserName, "UTF-8");
//Hidden fields also used for verification
String viewState = URLEncoder.encode("/wEPDwULLTIxMTU1NzMyNDgPZBYCAgMPZBYCAgkPPCsADQBkGAEFAmd2D2dkNyI00Mr5sftsfyEsC6YBMNkj9mI=", "UTF-8");
String eventvalidation = URLEncoder.encode("/wEWBAK2l8HDAQKQoJfyDwK6z/31BQLCi9reA4vQxgNI61f/aeA7+HYbm+y+7y3g", "UTF-8");
String content = "tbxRacerName="+encodedLoginUserName+"&__VIEWSTATE="+viewState+"&__EVENTVALIDATION="+eventvalidation;
return content;
}
/**
* Makes a HTTP POST to the target URL by using an HttpURLConnection.
*
* @param targetUrl
* The URL to which the HTTP POST is made.
*
* @param content
* The contents which will be POSTed to the target URL.
*
* @return
* The open URLConnection which can be used to read any response.
*
* @throws IOException
*/
public HttpURLConnection doHttpPost(String targetUrl, String content) throws IOException
{
HttpURLConnection urlConnection = null;
DataOutputStream dataOutputStream = null;
try
{
// Open a connection to the target URL
// throws IOException
urlConnection = (HttpURLConnection)(new URL(targetUrl).openConnection());
// Specifying that we intend to use this connection for input
urlConnection.setDoInput(true);
// Specifying that we intend to use this connection for output
urlConnection.setDoOutput(true);
// Specifying the content type of our post
urlConnection.setRequestProperty("Content-Type", POST_CONTENT_TYPE);
// Specifying the method of HTTP request which is POST
// throws ProtocolException
urlConnection.setRequestMethod("POST");
// Prepare an output stream for writing data to the HTTP connection
// throws IOException
dataOutputStream = new DataOutputStream(urlConnection.getOutputStream());
// throws IOException
dataOutputStream.writeBytes(content);
dataOutputStream.flush();
dataOutputStream.close();
return urlConnection;
}
catch(IOException ioException)
{
System.out.println("I/O problems while trying to do a HTTP post.");
ioException.printStackTrace();
// Good practice: clean up the connections and streams
// to free up any resources if possible
if (dataOutputStream != null)
{
try
{
dataOutputStream.close();
}
catch(Throwable ignore)
{
// Cannot do anything about problems while
// trying to clean up. Just ignore
}
}
if (urlConnection != null)
{
urlConnection.disconnect();
}
// throw the exception so that the caller is aware that
// there was some problems
throw ioException;
}
}
/**
* Read response from the URL connection
*
* @param urlConnection
* The URLConncetion from which the response will be read
*
* @return
* The response read from the URLConnection
*
* @throws IOException
* When problems encountered during reading the response from the
* URLConnection.
*/
private String readResponse(HttpURLConnection urlConnection) throws IOException
{
BufferedReader bufferedReader = null;
try
{
// Prepare a reader to read the response from the URLConnection
// throws IOException
bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
HttpURLConnection.setFollowRedirects(false);
urlConnection.connect();
System.out.println(urlConnection.getHeaderFields());
System.out.println("URL: "+urlConnection.getURL());
String responeLine;
// Good Practice: Use StringBuilder in this case
StringBuilder response = new StringBuilder();
// Read untill there is nothing left in the stream
// throws IOException
while ((responeLine = bufferedReader.readLine()) != null)
{
response.append(responeLine);
}
return response.toString();
}
catch(IOException ioException)
{
System.out.println("Problems while reading the response");
ioException.printStackTrace();
// throw the exception so that the caller is aware that
// there was some problems
throw ioException;
}
finally
{
// Good practice: clean up the connections and streams
// to free up any resources if possible
if (bufferedReader != null)
{
try
{
// throws IOException
bufferedReader.close();
}
catch(Throwable ignore)
{
// Cannot do much with exceptions doing clean up
// Ignoring all exceptions
}
}
}
}
}
答案 0 :(得分：0)
我只需要网址。所以我不需要readResponse方法
是的，你这样做。该URL是 in 响应，可以是数据，也可以是标题。
有趣的是。 ; - ）但是当我删除它时程序不起作用
和2）发布后，有一个重定向到另一个页面
在回复中返回给您。
至少你需要调用getResponseCode（）。