1.工具
httpClient jar包
任意抓包工具 推薦 firefox的 firebug（非常好用）

在使用httpClient進行模擬登入時，有時候會遇到需要輸入驗證碼的情況。而對驗證碼進行識別的方法既費時效果還不好。這裡提供一個取巧的方法，即使用瀏覽器登入時產生的cookie進行登入。

2.上程式碼
首先是一個模擬http請求的工具類

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.List;

import org.apache.http.HttpEntity
 
;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.config.CookieSpecs;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache
 
.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class Http {

    static CloseableHttpClient httpclient = null;
 

    static RequestConfig requestConfig = null;

    static {
         requestConfig = RequestConfig.custom().setCookieSpec(CookieSpecs.BEST_MATCH).build();
         httpclient = HttpClients.custom().setDefaultRequestConfig(requestConfig).build();
    }




    public static String doGet(String url) {


        RequestConfig requestConfig = RequestConfig.custom().setCookieSpec(CookieSpecs.BEST_MATCH).build();
         CloseableHttpClient   httpclient = HttpClients.custom().setDefaultRequestConfig(requestConfig).build();
        try {  
           // 建立httpget.    
           HttpGet httpget = new HttpGet(url);
           httpget.addHeader("Cookie", "xxxxxxx");
           httpget.addHeader("Accept-Encoding","gzip, deflate");
           httpget.addHeader("Accept-Language","zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3");
           httpget.addHeader("Cache-Control","no-cache");
           httpget.addHeader("Connection","keep-alive");
           httpget.addHeader("Content-Type","application/json; charset=UTF-8");
           httpget.addHeader("Referer","http://www.zhihu.com/");
           httpget.addHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Firefox/38.0");
           System.out.println("executing request " + httpget.getURI());  
           // 執行get請求.    
           CloseableHttpResponse response = httpclient.execute(httpget); 
           try {  
               // 獲取響應實體    
               HttpEntity entity = response.getEntity();  
               System.out.println("--------------------------------------");  
               // 列印響應狀態    
               System.out.println(response.getStatusLine());  
               if (entity != null) {  
                return EntityUtils.toString(entity);
               }  
               System.out.println("------------------------------------");  
           } finally {  
               response.close();  
           }  
       } catch (ClientProtocolException e) {  
           e.printStackTrace();  
       } catch (ParseException e) {  
           e.printStackTrace();  
       } catch (IOException e) {  
           e.printStackTrace();  
       } 
        return null;
    }


    /**以utf-8形式讀取*/
    public static String doPost(String url,List<NameValuePair> formparams) {
        return doPost(url, formparams,"UTF-8");
    }

    public static String doPost(String url,List<NameValuePair> formparams,String charset) {
         RequestConfig requestConfig = RequestConfig.custom().setCookieSpec(CookieSpecs.BEST_MATCH).build();
         CloseableHttpClient httpclient = HttpClients.custom().setDefaultRequestConfig(requestConfig).build();
        // 建立預設的httpClient例項.    
       // CloseableHttpClient httpclient = HttpClients.createDefault(); 
     // 建立httppost    
        HttpPost httppost = new HttpPost(url); 
        httppost.addHeader("Cookie", "xxxxxxx");
        httppost.addHeader("Accept-Encoding","gzip, deflate");
        httppost.addHeader("Accept-Language","zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3");
        httppost.addHeader("Cache-Control","no-cache");
        httppost.addHeader("Connection","keep-alive");
        httppost.addHeader("Content-Type","application/json; charset=UTF-8");
        httppost.addHeader("Referer","http://www.zhihu.com/");
        httppost.addHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Firefox/38.0");


        UrlEncodedFormEntity uefEntity;
        try {
            uefEntity = new UrlEncodedFormEntity(formparams, charset);
            httppost.setEntity(uefEntity);
            CloseableHttpResponse response = httpclient.execute(httppost);
            try {
                // 列印響應狀態    
                System.out.println(response.getStatusLine());
                 HttpEntity entity = response.getEntity(); 
                 if (entity != null) {  
                    return EntityUtils.toString(entity);
                 }  
            } finally {  
                response.close();  
            }  
        } catch (ClientProtocolException e) {  
            e.printStackTrace();  
        } catch (UnsupportedEncodingException e1) {  
            e1.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        } 
        return null;
    }
}

httppost.addHeader(“Cookie”, “xxxxxxx”); 這裡xxxxxx的即為登入時產生的cookie 由於每個瀏覽器產生的cookie不盡相同，故以xxxxx代替

測試類 這裡模擬登入的是知乎

public class Test {


    public static void main(String[] args) {
        String content = Http.doGet("http://www.zhihu.com/");
        System.out.println(content);
    }

}

測試結果