Java中的代理原理及代理使用示例

//以下地址是代理服务器的地址 
Socket socket = new Socket("10.1.2.188", 80); 
//写与的内容就是遵循HTTP请求协议格式的内容，请求百度 
socket.getOutputStream().write(new String("GET http://www.baidu.com/ HTTP/1.1\r\n\r\n").getBytes()); 
byte[] bs = new byte[1024]; 
InputStream is = socket.getInputStream(); 
int i; 
while ((i = is.read(bs)) > 0) { 
    System.out.println(new String(bs, 0, i)); 
} 
is.close(); 

//设置代理 
System.setProperty("http.proxySet", "true"); 
System.setProperty("http.proxyHost", "10.1.2.188"); 
System.setProperty("http.proxyPort", "80"); 
 
//直接访问目的地址 
URL url = new URL("http://www.baidu.com"); 
URLConnection con = url.openConnection(); 
InputStreamReader isr = new InputStreamReader(con.getInputStream()); 
char[] cs = new char[1024]; 
int i = 0; 
while ((i = isr.read(cs)) > 0) { 
    System.out.println(new String(cs, 0, i)); 
} 
isr.close(); 

SocketChannel sc = SocketChannel.open(new InetSocketAddress("10.1.2.188", 80)); 
 
sc.write(Charset.forName("utf8").encode("GET http://www.baidu.com/ HTTP/1.1\r\n\r\n")); 
 
ByteBuffer buffer = ByteBuffer.allocate(1024); 
 
while (sc.read(buffer) != -1) { 
    buffer.flip(); 
    System.out.println(Charset.forName("utf8").decode(buffer)); 
    buffer.clear(); 
} 
sc.close(); 

    public static void main(String[] args) {
        Properties prop = System.getProperties();
        // 设置http访问要使用的代理服务器的地址
        prop.setProperty("http.proxyHost", "192.168.0.254");
        // 设置http访问要使用的代理服务器的端口
        prop.setProperty("http.proxyPort", "8080");
        // 设置不需要通过代理服务器访问的主机，可以使用*通配符，多个地址用|分隔
        prop.setProperty("http.nonProxyHosts", "localhost|192.168.0.*");
        // 设置安全访问使用的代理服务器地址与端口
        // 它没有https.nonProxyHosts属性，它按照http.nonProxyHosts 中设置的规则访问
        prop.setProperty("https.proxyHost", "192.168.0.254");
        prop.setProperty("https.proxyPort", "443");
        // 使用ftp代理服务器的主机、端口以及不需要使用ftp代理服务器的主机
        prop.setProperty("ftp.proxyHost", "192.168.0.254");
        prop.setProperty("ftp.proxyPort", "2121");
        prop.setProperty("ftp.nonProxyHosts", "localhost|192.168.0.*");
        // socks代理服务器的地址与端口
        prop.setProperty("socksProxyHost", "192.168.0.254");
        prop.setProperty("socksProxyPort", "8000");
        // 设置登陆到代理服务器的用户名和密码
        Authenticator.setDefault(new MyAuthenticator("userName", "Password"));
    }
    static class MyAuthenticator extends Authenticator {
        private String user = "";
        private String password = "";
        public MyAuthenticator(String user, String password) {
            this.user = user;
            this.password = password;
        }
        protected PasswordAuthentication getPasswordAuthentication() {
            returnnew PasswordAuthentication(user, password.toCharArray());
        }
    }

    public static void main(String[] args) {
        try {
            URL url = new URL("http://www.baidu.com");
            // 创建代理服务器
            InetSocketAddress addr = new InetSocketAddress("192.168.0.254",
                    8080);
            // Proxy proxy = new Proxy(Proxy.Type.SOCKS, addr); // Socket 代理
            Proxy proxy = new Proxy(Proxy.Type.HTTP, addr); // http 代理
            // 如果我们知道代理server的名字, 可以直接使用
            // 结束
            URLConnection conn = url.openConnection(proxy);
            InputStream in = conn.getInputStream();
            // InputStream in = url.openStream();
            String s = IOUtils.toString(in);
            System.out.println(s);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }