使用Java URLConnection进行Cookie管理

Question

我对Android编程很新,最近获得了成功的HTTP Post请求,只是为了了解我的cookie没有存储在后续的Post/Get请求之间.我浏览了一下interweb,并找到了Android的Apache客户端和Java的HttpURLConnection的几个例子.我没有成功地将这两种方法应用到我当前的课程中,所以我想知道有经验的人是否可以查看我的代码并提供建议.

概括:

1. 我的初始POST请求成功并经过身份验证.
2. 我的第二个POST请求不保留初始POST请求中的cookie.
3. 是否有人为可能选择Apache方法或Java实现的具体实例或原因？两者都是平等的,还是一个提供比另一个更多的能力和灵活性？

感谢任何帮助,谢谢.

webCreate.java

import android.util.Log;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.CookieHandler;
import java.net.CookieManager;
import java.net.HttpCookie;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.net.ssl.HttpsURLConnection;

public class webCreate {

    private final String USER_AGENT = "Mozilla/5.0";


    // HTTP GET request
    public void sendGet(String url) throws Exception {

        CookieManager cookieManager = new CookieManager();
        CookieHandler.setDefault(cookieManager);
        HttpCookie cookie = new HttpCookie("lang", "en");


        URL obj = new URL(url);
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();

        // optional default is GET
        con.setRequestMethod("GET");

        //add request header
        con.setRequestProperty("User-Agent", USER_AGENT);

        int responseCode = con.getResponseCode();
        Log.d("sendGet", "\nSending 'GET' request to URL : " + url);


        BufferedReader in = new BufferedReader(
                new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();


        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }

        in.close();

        //print result
        System.out.println(response.toString());
        Log.d("Response Code", response.toString());
    }

    // HTTP POST request
    String  sendPost(String url, String urlParams) throws Exception {

        CookieManager cookieManager = new CookieManager();
        CookieHandler.setDefault(cookieManager);
        HttpCookie cookie = new HttpCookie("lang", "en");

        URL obj = new URL(url);
        HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();

        //add request header
        con.setRequestMethod("POST");
        con.setRequestProperty("User-Agent", USER_AGENT);
        con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");

        // Send post request
        con.setDoOutput(true);
        DataOutputStream wr = new DataOutputStream(con.getOutputStream());
        wr.writeBytes(urlParams);
        wr.flush();
        wr.close();

        int responseCode = con.getResponseCode();
        System.out.println("\nSending 'POST' request to URL : " + url);
        System.out.println("Post parameters : " + urlParams);
        System.out.println("Response Code : " + responseCode);

        BufferedReader in = new BufferedReader(
                new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();

        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        System.out.println("Response Code : " + response);
        return  response.toString();
    }

}

Answer 1

您需要在每个调用之外维护您的cookie上下文,并在后续GET和POST上提供相同的cookie存储它.对于Java实现和Apache的实现,这都是相同的.

根据我的经验,Apache的HTTP组件比内置的Java实现更好.我花了很多时间尝试使用Java的实现来编写实用程序,我最大的问题是超时.错误的Web服务器会挂起,导致连接无限期挂起.切换到Apache后,超时是可调的,我们没有任何更多的挂起线程.

我将举一个使用Apache的例子.

CookieStore在父方法中创建实例:

CookieStore cookieStore = new BasicCookieStore();

然后在您的GET或POST实现中传入CookieStore实例并在构建HttpClient时使用它:

public void sendGet(String url, CookieStore cookieStore) throws Exception {
    ...
    HttpClient client = HttpClientBuilder.create().setDefaultCookieStore(cookieStore).build();

    HttpGet request = new HttpGet(uri);  // or HttpPost...
    request.addHeader("User-Agent", USER_AGENT);
    HttpResponse response = client.execute(request);

    BufferedReader br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
    ...
}

Android已经扩展java.net.HttpURLConnection并建议使用它,所以我也会给出一个大纲.

HttpURLConnection并HttpsURLConnection自动透明地使用该CookieManager集CookieHandler. CookieHandler在VM范围内,因此必须只设置一次.如果您CookieManager为每个请求创建一个新的,就像在代码中一样,它将清除以前请求中设置的任何cookie.

您不需要创建HttpCookie自己的实例.当HttpURLConnection从服务器CookieManager接收cookie时,将接收cookie并存储它.对同一服务器的未来请求将自动发送先前设置的cookie.

因此,将此代码移动到您的应用程序设置,以便它只发生一次:

CookieManager cookieManager = new CookieManager();
CookieHandler.setDefault(cookieManager);