完全代码
package com.proj.net;
//导入编码的jar文件
import it.sauronsoftware.base64.Base64;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
/**
* 很多公司会对网上进行限制，要通过代理http://www.wfuyu.com/server/和口令才能连接外网。<br>
* 这类方式有很多好处：<br>
* 1、安全，代理http://www.wfuyu.com/server/像1层过滤层；<br>
* 2、节省本钱，只需要分配很少的IP地址便可；<br>
* 3、对员工上网可以个性化配置，避免有人下载大量数据而造成网络拥堵不堪。<br>
*
* 本文通过1个小案例来介绍如何在程序里跨过局域网访问外网。<br>
* 对弄网络开发的人来讲，不值1提；但对做JAVA EE利用开发的人来讲，可以参考。<br>
*
* @author 王1洋
*
* 2014⑴0⑶0
* */
public class Test {
public static void main(String[] args) {
try {
//两种方式设置代理http://www.wfuyu.com/server/
//设置代理1
//Proxy proxy = new Proxy(Proxy.Type.HTTP,new InetSocketAddress("", 80));
//设置代理2
System.getProperties().setProperty( "http.proxyHost", "");
System.getProperties().setProperty( "http.proxyPort", "" );
String urlString = "http://blog.csdn.net/";
URL url = new URL(urlString);
//对应第1种设置方式
//HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection(proxy);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setConnectTimeout(1000);
//设置User Agent
urlConnection.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
//设置访问的用户名和密码
urlConnection.setRequestProperty( "Proxy-Authorization", "Basic" + Base64.encode("username:password") );
urlConnection.connect();
System.out.print(urlConnection.getResponseCode());
BufferedInputStream bis = new BufferedInputStream(urlConnection.getInputStream());
InputStreamReader isr = new InputStreamReader(bis,"UTF⑻");
BufferedReader bufferedReader = new BufferedReader(isr);
String str = "";
StringBuffer buffer = new StringBuffer("");
while((str = bufferedReader.readLine())!=null){
buffer.append(str+"
");
}
System.out.println(buffer);
} catch (Exception e) {
e.printStackTrace();
}
}
}
返回code：200，OK！
异常Server returned HTTP response code: 403
for URL
在url.openConnection()后添加：
connection.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");