關於java socket的問題

問題
要做成這樣的：

Client Access Serverip和port，伺服器馬上發送welcome訊息，然後用戶端根據welcome訊息判斷是否是想要已連線的服務器和連接埠，

如果是則開始發送資料，資料包括開始和結束的校正。伺服器端發送welcome訊息後開始接收資料，直到結束。蠻簡單的事TMD我怎麼就搞不定。

CLIENT：

package com.ces.mytest.socket;

import java.net.*;import java.io.*;

public class ClientThread extends Thread {    private String ipStr = "";    private int port;    public ClientThread(String ipStr, int port) {        this.ipStr = ipStr;        this.port = port;    }

    public void run() {        try {            Socket client = new Socket(ipStr, port);            BufferedReader read = new BufferedReader(new InputStreamReader(client.getInputStream()));            BufferedWriter write = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));

            if ("歡迎".equals(read.readLine())) {                System.out.println("校正正確");

                write.write("開始");                write.newLine();                write.write("資料");                write.newLine();                write.write("結束");                write.newLine();                write.flush();

                System.out.println("發送完畢");            }

            write.close();            read.close();            client.close();        } catch (UnknownHostException ex) {            ex.printStackTrace();        } catch (IOException ex) {            ex.printStackTrace();        }    }

    public static void main(String[] args) {        Thread client = new ClientThread("127.0.0.1",10020);        client.start();    }

}

SERVER：

package com.ces.mytest.socket;

import java.net.*;import java.io.*;

public class ServerThread extends Thread {    private int port;    public ServerThread(int port) {        this.port = port;    }

    private boolean stop = false;

    public void run() {        try {            ServerSocket server = new ServerSocket(port);            while (!stop) {                Socket client = server.accept();                BufferedReader read = new BufferedReader(new InputStreamReader(client.getInputStream()));                BufferedWriter write = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));                                System.out.println("發送歡迎資訊");                                write.write("歡迎");                write.flush();

//                String lineStr = read.readLine();//                if ("開始".equals(lineStr)) {//                    System.out.println("開始接受資料！");////                    while (true) {//                        lineStr = read.readLine();//                        if ("結束".equals(lineStr)) {//                            break;//                        } else {//                            System.out.println("資料是" + lineStr);//                        }//                    }//                }

                write.close();                read.close();                client.close();            }

        } catch (IOException ex) {            ex.printStackTrace();        }    }

    public static void main(String[] args) {        Thread server = new ServerThread(10020);        server.start();    }

    public boolean isStop() {        return stop;    }

    public void setStop(boolean stop) {        this.stop = stop;    }}

只要我將ServerThread類的String lineStr = read.readLine();的注釋去掉，程式肯定出問題，什麼問題呢？分析發現ServerThread的Output流必須等write.close()執行完才發送，而read.readLine()程式就會停在那裡，所謂的block程式，可參考上明明說write.flush()即可發送啊，搞不懂搞不懂，這樣我的握手協議怎麼做啊？？