Java实现TCP穿透NAT技术该怎么实现
在做一个远程文件管理系统的时候，需要用到TCP穿透NAT技术，在网上找了很多的资料都是理论的讲解，根据理论自己琢磨了好几天，程序还是一直都有问题。请教一下高手，该怎么实现TCP穿透NAT呀！！！



我把我自己写的代码贴出来，大家看看该怎么改嘛。
在线等呃。。。

服务器的代码：
public class TcpServer{
public static int count = 0;
public static ArrayList<InetAddress> list_address_1 = new ArrayList<InetAddress>();
public static ArrayList<InetAddress> list_address_2 = new ArrayList<InetAddress>();
public static ArrayList<String> list_port_1 = new ArrayList<String>();
public static ArrayList<String> list_port_2 = new ArrayList<String>();
public static ArrayList<Socket> list_socket = new ArrayList<Socket>();

public TcpServer() {
try {
ServerSocket s_socket = new ServerSocket(6789);
System.out.println("服务器开始监听6789端口");
while(true) {
Socket socket = s_socket.accept();
System.out.println("客户端的IP：" + socket.getInetAddress() + "\t客户端的端口号是：" + socket.getPort());
System.out.println("IP:" + socket.getLocalAddress() + "\tPort:" + socket.getLocalPort());
try {
System.out.println("Socket is " + socket);
Thread input = new InputThread(socket.getInputStream(), socket);
input.start();
System.out.println("写入线程开启...");
Thread output = new OutputThread(socket.getOutputStream());
output.start();
System.out.println("输出线程开启...");
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("Message is " + e.getMessage());
e.printStackTrace();
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("Message " + e.getMessage());
e.printStackTrace();
}
}

public static void connect() {
Socket socket_1 = list_socket.get(0);
Socket socket_2 = list_socket.get(1);
OutputStream out_1 = null;
OutputStream out_2 = null;
try {
out_1 = socket_1.getOutputStream();
out_2 = socket_2.getOutputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("Conect " + e.getMessage());
e.printStackTrace();
}
Writer writer_1 = new OutputStreamWriter(out_1);
Writer writer_2 = new OutputStreamWriter(out_2);
String str_1_1 = new String(list_address_1.get(1).toString().getBytes(), 1, list_address_1.get(1).toString().getBytes().length - 1);
String str_1_2 = new String(list_address_2.get(1).toString().getBytes(), 1, list_address_2.get(1).toString().getBytes().length - 1);
String str_2_1 = new String(list_address_1.get(0).toString().getBytes(), 1, list_address_1.get(0).toString().getBytes().length - 1);
String str_2_2 = new String(list_address_2.get(0).toString().getBytes(), 1, list_address_2.get(0).toString().getBytes().length - 1);
String msg_1 = "<connection>:" + str_1_1 + ":" + list_port_1.get(1) + ":" + str_1_2 + ":" + list_port_2.get(1);
String msg_2 = "<connection>:" + str_2_1 + ":" + list_port_1.get(0) + ":" + str_2_2 + ":" + list_port_2.get(0);
try {
writer_1.write(msg_1);
writer_1.flush();
writer_2.write(msg_2);
writer_2.flush();
System.out.println("开始中转连接");
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("456_" + e.getMessage());
e.printStackTrace();
}
}

public static void main(String[] args) {
new TcpServer();
}
}

class InputThread extends Thread {
InputStream in = null;
Socket socket = null;
public InputThread(InputStream input, Socket socket) {
this.in = input;