深沉的船

在学校园网，要代理才可上网。写程序获取网上资源时，怎么办呢？同样可以为程序设置代理。我用HttpClient的3.1版本。有些网站要浏览器才可以访问，但程序可以仿浏览器，主要是设置http头。

在HostConfiguration.setProxy里设置。如下面代码：

 
   package com.skydong;  
      
    import java.io.IOException;  
    import java.util.ArrayList;  
    import java.util.List;  
     
   import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;  
   import org.apache.commons.httpclient.Header;  
   import org.apache.commons.httpclient.HttpClient;  
   import org.apache.commons.httpclient.HttpException;  
   import org.apache.commons.httpclient.HttpStatus;  
   import org.apache.commons.httpclient.UsernamePasswordCredentials;  
   import org.apache.commons.httpclient.auth.AuthScope;  
   import org.apache.commons.httpclient.methods.GetMethod;  
   import org.apache.commons.httpclient.params.HttpMethodParams;  
     
   public class HttpClientUse {  
     
       public static void main(String[] args) throws HttpException, IOException {  
           HttpClient httpClient = new HttpClient();  
     
           httpClient.getHostConfiguration().setProxy("localhost", 808);  
     
           /*//需要验证 
           UsernamePasswordCredentials creds = new UsernamePasswordCredentials("chenlb", "123456"); 
    
           httpClient.getState().setProxyCredentials(AuthScope.ANY, creds); 
           */  
    
           //设置http头  
           List<Header> headers = new ArrayList<Header>();  
           headers.add(new Header("User-Agent", "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)"));  
           httpClient.getHostConfiguration().getParams().setParameter("http.default-headers", headers);  
     
           GetMethod method = new GetMethod("http://www.baidu.com");  
           method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER,  
                   new DefaultHttpMethodRetryHandler(3, false));  
           try {  
               int statusCode = httpClient.executeMethod(method);  
     
               if (statusCode != HttpStatus.SC_OK) {  
                   System.out.println("Method failed code="+statusCode+": " + method.getStatusLine());  
     
               } else {  
                   System.out.println(new String(method.getResponseBody(), "gb2312"));  
               }  
           } finally {  
              method.releaseConnection();  
           }  
       }  
   }  

package com.skydong; <br/> <br/> import java.io.IOException; <br/> import java.util.ArrayList; <br/> import java.util.List; <br/> <br/> import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler; <br/> import org.apache.commons.httpclient.Header; <br/> import org.apache.commons.httpclient.HttpClient; <br/> import org.apache.commons.httpclient.HttpException; <br/> import org.apache.commons.httpclient.HttpStatus; <br/> import org.apache.commons.httpclient.UsernamePasswordCredentials; <br/> import org.apache.commons.httpclient.auth.AuthScope; <br/> import org.apache.commons.httpclient.methods.GetMethod; <br/> import org.apache.commons.httpclient.params.HttpMethodParams; <br/> <br/> public class HttpClientUse { <br/> <br/> public static void main(String[] args) throws HttpException, IOException { <br/> HttpClient httpClient = new HttpClient(); <br/> <br/> httpClient.getHostConfiguration().setProxy("localhost", 808); <br/> <br/> /*//需要验证 <br/> UsernamePasswordCredentials creds = new UsernamePasswordCredentials("chenlb", "123456"); <br/> <br/> httpClient.getState().setProxyCredentials(AuthScope.ANY, creds); <br/> */ <br/> <br/> //设置http头 <br/> List<Header> headers = new ArrayList<Header>(); <br/> headers.add(new Header("User-Agent", "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)")); <br/> httpClient.getHostConfiguration().getParams().setParameter("http.default-headers", headers); <br/> <br/> GetMethod method = new GetMethod("http://www.baidu.com"); <br/> method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, <br/> new DefaultHttpMethodRetryHandler(3, false)); <br/> try { <br/> int statusCode = httpClient.executeMethod(method); <br/> <br/> if (statusCode != HttpStatus.SC_OK) { <br/> System.out.println("Method failed code="+statusCode+": " + method.getStatusLine()); <br/> <br/> } else { <br/> System.out.println(new String(method.getResponseBody(), "gb2312")); <br/> } <br/> } finally { <br/> method.releaseConnection(); <br/> } <br/> } <br/> }
如果要用户名与密码验证的，请把/* */注释去掉。使验证有效。

验证，关键是：

 
   UsernamePasswordCredentials creds = new UsernamePasswordCredentials("chenlb", "123456");  
   httpClient.getState().setProxyCredentials(AuthScope.ANY, creds); 

UsernamePasswordCredentials creds = new UsernamePasswordCredentials("chenlb", "123456"); <br/> httpClient.getState().setProxyCredentials(AuthScope.ANY, creds);
设置http请求头.

 List<Header> headers = new ArrayList<Header>();  
 headers.add(new Header("User-Agent", "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)"));  
httpClient.getHostConfiguration().getParams().setParameter("http.default-headers", headers); 

List<Header> headers = new ArrayList<Header>(); <br/> headers.add(new Header("User-Agent", "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)")); <br/>httpClient.getHostConfiguration().getParams().setParameter("http.default-headers", headers); <br/>