JAVA使用HTTP代码示例

import java.io.ByteArrayOutputStream;
    import java.io.InputStream;
    import java.net.Authenticator;
    import java.net.HttpURLConnection;
    import java.net.InetSocketAddress;
    import java.net.PasswordAuthentication;
    import java.net.Proxy;
    import java.net.URL;

    class ProxyAuthenticator extends Authenticator {
        private String user, password;

        public ProxyAuthenticator(String user, String password) {
            this.user     = user;
            this.password = password;
        }

        protected PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(user, password.toCharArray());
        }
    }

    /**
     * 注意：下面代码仅仅实现HTTP请求链接，每一次请求都是无状态保留的，仅仅是这次请求是更换IP的，如果下次请求的IP地址会改变
     * 如果是多线程访问的话，只要将下面的代码嵌入到你自己的业务逻辑里面，那么每次都会用新的IP进行访问，如果担心IP有重复，
     * 自己可以维护IP的使用情况，并做校验。
     */
    public class ProxyDemo {
        public static void main(String args[]) throws Exception {
            // 要访问的目标页面
            String targetUrl = "http://ip.hahado.cn/ip";
            //String targetUrl = "http://ip.hahado.cn/switch-ip";
            //String targetUrl = "http://ip.hahado.cn/current-ip";

            // 代理服务器
            String proxyServer = "ip.hahado.cn";
            int proxyPort      = 39010;

            // 代理隧道验证信息
            String proxyUser  = "username";
            String proxyPass  = "password";

            try {
                URL url = new URL(targetUrl);

                Authenticator.setDefault(new ProxyAuthenticator(proxyUser, proxyPass));

                // 创建代理服务器地址对象
                InetSocketAddress addr = new InetSocketAddress(proxyServer, proxyPort);
                // 创建HTTP类型代理对象
                Proxy proxy = new Proxy(Proxy.Type.HTTP, addr);

                // 设置通过代理访问目标页面
                HttpURLConnection connection = (HttpURLConnection) url.openConnection(proxy);
                // 设置IP切换头
                connection.setRequestProperty("Proxy-Switch-Ip","yes");

                // 解析返回数据
                byte[] response = readStream(connection.getInputStream());

                System.out.println(new String(response));
            } catch (Exception e) {
                System.out.println(e.getLocalizedMessage());
            }
        }

        /**
         * 将输入流转换成字符串
         *
         * @param inStream
         * @return
         * @throws Exception
         */
        public static byte[] readStream(InputStream inStream) throws Exception {
            ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int len = -1;

            while ((len = inStream.read(buffer)) != -1) {
                outSteam.write(buffer, 0, len);
            }
            outSteam.close();
            inStream.close();

            return outSteam.toByteArray();
        }
    }