一句一句的翻译一下这段代码public class Client int port = 8888; String ip = localhost; DataInputStream di = null; DataOutputStream dou = null; Socket client = null; socket 通常也称作套接字用于描述IP地址和端口是一个通信链的

public class Client { int port = 8888; String ip = "localhost"; DataInputStream di = null; DataOutputStream dou = null; Socket client = null;

// This is a constructor to initialize the socket
public Client() throws UnknownHostException, IOException {
    client = new Socket(ip, port);
    run();
}

// Transfer the seq value and add 1 to form the ack value
public String seqTransferAck(String s) {
    String result = null;
    int i = Integer.parseInt(s);
    i = i + 1;
    result = String.valueOf(i);
    return result;
}

// Send messages to the server
public void run() throws IOException {
    di = new DataInputStream(client.getInputStream());
    dou = new DataOutputStream(client.getOutputStream());
    // First handshake, data sent from client to server. seq=random number SYN=1 ACK=0
    seq = new Random().nextInt(1000)+"";
    ack = "0";
    SYN = "1";
    ACK = "0";
    // Write the data to be sent to the server into the data output stream
    dou.writeUTF(SYN);
    dou.writeUTF(ACK);
    dou.writeUTF(seq);


}

public String[] secendhand() throws Exception{
    di = new DataInputStream(client.getInputStream());
    dou = new DataOutputStream(client.getOutputStream());
    // Second handshake, read data from the server
    String str[] = new String[4];
    serverSYN = di.readUTF();// SYN
    serverACK = di.readUTF();// ACK
    serverseq = di.readUTF();// seq
    serverack = di.readUTF();//
    str[0] = serverSYN;
    str[1] = serverACK;
    str[2] = serverseq;
    str[3] = serverack;
    return str;
}

public void secendPrint()throws Exception{
    System.out.println("Second handshake");
    System.out.println("ACK received from the server=" + serverSYN);
    System.out.println("SYN received from the server=" + serverACK);
    System.out.println("seq received from the server=" + serverseq);
    System.out.println("ack received from the server=" + serverack);
    // Third handshake, data sent from client to server. Set seq=serverack SYN=0 ACK=1 ack=seqTransferAck(serverseq)
    ACK = "1";
    SYN = "0";
    ack = seqTransferAck(serverseq);
    dou.writeUTF(ACK);
    dou.writeUTF(SYN);
    dou.writeUTF(serverack);
    dou.writeUTF(ack);
}

//[start] Four-way handshake
/**
 * Four-way handshake process to terminate the TCP connection
 * First handshake: fin = 1, seq = u
 * Second handshake: ACK = 1, seq = v, ack = u+1
 * Third handshake: fin = 1, ACK=1, seq = w, ack = u+1
 * Fourth handshake: ACK = 1, seq = u+1, ack = w+1
 */

public void fouthsend() throws Exception{
    di = new DataInputStream(client.getInputStream());
    dou = new DataOutputStream(client.getOutputStream());
    seq = new Random().nextInt(1000)+"";
    dou.writeUTF(fin);
    dou.writeUTF(seq);
}

public String[] fifthhand() throws Exception{
    di = new DataInputStream(client.getInputStream());
    dou = new DataOutputStream(client.getOutputStream());
    String str[] = new String[4];
    RecACK2 = di.readUTF();
    Recseq2 = di.readUTF();
    Recack2 = di.readUTF();
    str[0] = RecACK2;
    str[1] = Recseq2;
    str[2] = Recack2;
    return str;
}

public void fifthPrint()throws Exception{
    System.out.println("Second handshake");
    System.out.println("ACK received from the server=" + RecACK2);
    System.out.println("seq received from the server=" + Recseq2);
    System.out.println("ack received from the server=" + Recack2);
}

public String[] sixthhand() throws Exception{
    di = new DataInputStream(client.getInputStream());
    dou = new DataOutputStream(client.getOutputStream());
    String str[] = new String[4];
    Recfin3 = di.readUTF();
    Recseq3 = di.readUTF();
    Recack3 = di.readUTF();
    str[0] = Recfin3;
    str[1] = Recseq3;
    str[2] = Recack3;
    return str;
}

public void sixthPrint()throws Exception{
    System.out.println("Third handshake");
    System.out.println("FIN received from the server=" + Recfin3);
    System.out.println("seq received from the server=" + Recseq3);
    System.out.println("ack received from the server=" + Recack3);
    String RecACK4 = "1";
    String Recseq4 = seqTransferAck(seq);
    String Recack4 = seqTransferAck(Recseq3);
    dou.writeUTF(RecACK4);
    dou.writeUTF(Recseq4);
    dou.writeUTF(Recack4);
}