HttpClient HTTP/1.1 302 对象已移动

Question

该代码适用于我的简单测试登录表单。它使用 POST 登录，然后将所有信息从登录视图打印到屏幕上。但它不适用于我一直在创建此代码的某个特定网站。有什么想法为什么会发生这种情况以及如何解决它吗？

package visualutopiabot;

import org.apache.http.client.ResponseHandler;
import org.apache.http.impl.client.BasicResponseHandler;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

    public class Main {

        public static void main(String[] args) throws Exception {

            DefaultHttpClient httpclient = new DefaultHttpClient();
            try {

                /* POST login */
                HttpPost httpost = new HttpPost("http://website.com/login.asp");

                List <NameValuePair> nvps = new ArrayList <NameValuePair>();
                nvps.add(new BasicNameValuePair("username", "nnnnick"));
                nvps.add(new BasicNameValuePair("password", "pppassswww123"));

                httpost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));
                HttpResponse response = httpclient.execute(httpost);
                HttpEntity entity = response.getEntity();
                System.out.println("Login form get: " + response.getStatusLine());
                EntityUtils.consume(entity);

                /* get content*/
                HttpGet httpget = new HttpGet("http://website.com/index.asp");

                System.out.println("executing request " + httpget.getURI());

                // Create a response handler
                ResponseHandler<String> responseHandler = new BasicResponseHandler();
                String responseBody = httpclient.execute(httpget, responseHandler);
                System.out.println("----------------------------------------");
                System.out.println(responseBody);
                System.out.println("----------------------------------------");


            } finally {
                // When HttpClient instance is no longer needed,
                // shut down the connection manager to ensure
                // immediate deallocation of all system resources
                httpclient.getConnectionManager().shutdown();
            }
        }
    }

Answer 1

如果您使用httpclient 3x

GetMethod 将 followRedirects 标志设置为 true默认的

你可以试试将 PostMethod 的 set redirect 显式设置为 true

 PostMethod postMethod = ...;
 postMethod.setFollowRedirects(true)

如果您使用 httpcomponents

httpclient.setRedirectStrategy(new DefaultRedirectStrategy());
httpost.getParams().setParameter("http.protocol.handle-redirects",true);

请参阅http://hc.apache.org/httpcomponents-client-ga/tutorial/html/httpagent.html#d4e1192 了解更多详细信息

Answer 2

302表示页面已移动。您需要检查响应中的 Location 标头，然后对该标头中的 url 重试您的请求。

Answer 3

HTTP 代码 302 是进行重定向的一种方法。您的代码可能正确执行登录，然后服务器将其重定向到另一个页面。无论哪种方式，您都应该在响应中看到 Location: 标头并遵循它。

Answer 4

一直以来的答案是我发送了错误的 POST 查询。而不是：

nvps.add(new BasicNameValuePair("username", "nnnnick"));
nvps.add(new BasicNameValuePair("password", "pppassswww123"));

必须写：

nvps.add(new BasicNameValuePair("login", "nnnnick"));
nvps.add(new BasicNameValuePair("pw", "pppassswww123"));