HTTPClient模拟登陆人人网

• HttpClient(DefaultHttpClient)代表了一个会话，在同一个会话中，HttpClient对cookie自动进行管理(当然，也可以在程序中进行控制)。
• 在同一个会话中，当使用post或是get发起一个新的请求时，一般需要对调用前一个会话的abort()方法，否则会抛出异常。
• 有些网站登录成功后会重定向(302, 303)，比如这里的人人网。如果发出的是post请求，需要从响应头中取出location，并再次向网站发送请求，以获取最终数据。
• 抓取程序不要运行地过于频繁，大部分站点都有抵制刷网站机制。人人网访问过于频繁会锁账号。
• 使用录制工具录制出登录时向网站发出的请求参数。在这里，我使用了badboy，导出成jmeter文件，在jmeter中就可以看到登录时向网站发送的参数列表和相应的值。
• 人人网属于登陆流程比较简单的网站，后一篇会介绍一家比较难搞的网站。

public class RenRen {
    // The configuration items
    private static String userName = "YourMailinRenren";
    private static String password = "YourPassword";
    private static String redirectURL = "http://blog.renren.com/blog/304317577/449470467";

    // Don't change the following URL
    private static String renRenLoginURL = "http://www.renren.com/PLogin.do";

    // The HttpClient is used in one session
    private HttpResponse response;
    private DefaultHttpClient httpclient = new DefaultHttpClient();

    private boolean login() {
        HttpPost httpost = new HttpPost(renRenLoginURL);
        // All the parameters post to the web site
        List<NameValuePair> nvps = new ArrayList<NameValuePair>();
        nvps.add(new BasicNameValuePair("origURL", redirectURL));
        nvps.add(new BasicNameValuePair("domain", "renren.com"));
        nvps.add(new BasicNameValuePair("isplogin", "true"));
        nvps.add(new BasicNameValuePair("formName", ""));
        nvps.add(new BasicNameValuePair("method", ""));
        nvps.add(new BasicNameValuePair("submit", "登录"));
        nvps.add(new BasicNameValuePair("email", userName));
        nvps.add(new BasicNameValuePair("password", password));
        try {
            httpost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));
            response = httpclient.execute(httpost);
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        } finally {
            httpost.abort();
        }
        return true;
    }

    private String getRedirectLocation() {
        Header locationHeader = response.getFirstHeader("Location");
        if (locationHeader == null) {
            return null;
        }
        return locationHeader.getValue();
    }

    private String getText(String redirectLocation) {
        HttpGet httpget = new HttpGet(redirectLocation);
        // Create a response handler
        ResponseHandler<String> responseHandler = new BasicResponseHandler();
        String responseBody = "";
        try {
            responseBody = httpclient.execute(httpget, responseHandler);
        } catch (Exception e) {
            e.printStackTrace();
            responseBody = null;
        } finally {
            httpget.abort();
            httpclient.getConnectionManager().shutdown();
        }
        return responseBody;
    }

    public void printText() {
        if (login()) {
            String redirectLocation = getRedirectLocation();
            if (redirectLocation != null) {
                System.out.println(getText(redirectLocation));
            }
        }
    }

    public static void main(String[] args) {
        RenRen renRen = new RenRen();
        renRen.printText();
    }
}