小弟我做了一个客户端发送消息到服务器端，socket能连接上，但发送不了数据，不知为什么

// 客户端TCPClientimport  java.io.*;import  java.net.*;import java.util.Scanner;public class TCPClient {       private  static  int  sort=3434;       private  static  String host="localhost";  //本机ip地址      public  static  void main(String avg[]){          Scanner   input = new Scanner(System.in);                 BufferedReader  br=null;                 BufferedWriter  wr=null;                 Socket          s =null;            try{                                                                             while(true){                    System.out.print("客户端说:");                     String  line = input.nextLine();                    if(line.equals("byb"))  break;                        s=new Socket(TCPClient.host,TCPClient.sort);                    wr =new  BufferedWriter(new OutputStreamWriter( s.getOutputStream()));                      wr.write(line);                     wr.close();                    s.close();             //关闭会话                     try {                   //暂停一会儿!                        Thread.sleep(300);                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                        s=new Socket(TCPClient.host,TCPClient.sort);                    br =new  BufferedReader(new InputStreamReader( s.getInputStream()));                    System.out.print("接收端:");                    int   next=0;                    StringBuffer li=new StringBuffer();                    while((next=br.read()) != -1)  li.append((char)next);                    System.out.println(new String(li.toString()));                                      br.close();                    s.close();            关闭会话!                 }                             }catch(UnknownHostException e){                 System.out.println("服务器连接失败");                 e.printStackTrace();            }catch(IOException e){                 e.printStackTrace();            }      }}
------解决方案--------------------
 wr.write(line);后面加wr.flush();