socket 传输数据多字节问题 JAVA

客户段
====================package org.xpup.hafmis.signjoint.util;import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.*;
//import java.text.SimpleDateFormat;
//import java.util.Date;public class Client extends Thread {  public Client(InetAddress addr, String sendstr) throws IOException {
    Socket sk = null;
//    char a=0;
    String writeString, filesize = "";
//    FileOutputStream fo = null;
//    OutputStreamWriter osw = null;
    try {
      System.out.println("开始读取文件头................");
      String path = "d:\\other\\javac";
      File file = new File(path);
      File myfile = file.listFiles()[0];
      sk = new Socket(addr, 10001);
//      sk = new Socket("15.26.6.102", 9901);
//      sk = new Socket("119.108.13.232", 10001);
      String filename = myfile.getName();
      filename = filename.substring(0, filename.lastIndexOf("."));
      if(myfile.length()%4096!=0){
        filesize=(myfile.length()/4096+1)*4096+"";
      }else{
        filesize=myfile.length()+"";
      }
      filename = filename + "_" + filesize;
      System.out.println("sendstr......" + filename);
      OutputStream os = sk.getOutputStream();
      InputStream cis = sk.getInputStream();
      os.write(filename.getBytes());
      System.out.println("给中心传送文件头，说明我准备给中心发数据了");
      while (true) {
        byte[] buf = new byte[4096];
        if(cis.read(buf,0,4096)!=-1){
          writeString=new String(buf).trim();
          System.out.println("writeString...."+writeString);
          if (writeString.equals("READY")) {
            FileInputStream fi = new FileInputStream(myfile);
            for(int i=0;i<Integer.parseInt(filesize)/4096;i++){
              byte[] cbuf = new byte[4096];
              if(fi.read(cbuf,0,4096)!=-1){
                System.out.println("收到READY，发送第"+(i+1)+"个4096字节......");
                System.out.println("cbuf.toString()....."+new String(cbuf));
                os.write(cbuf);
              }
            }
            os.write("FILEOVER".getBytes());
            System.out.println("发送FILEOVER......");
          }else if (writeString.equals("FILEOK")) {
            System.out.println("收到FILEOK，结束socket.........");
            cis.close();
            os.close();
            sk.close();
            break;
          }else if (writeString.equals("FILEERR")) {
            System.out.println("收到FILEERR，结束socket.........并准备重新连接......");
            cis.close();
            os.close();
            sk.close();
            break;
          }else if (writeString.equals("END")) {
            System.out.println("收到END，结束socket.........");
            cis.close();
            os.close();
            sk.close();
            break;
          }
        }
      }    } catch (IOException e) {
      e.printStackTrace();
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
    }
  }  public static void main(String[] args) throws UnknownHostException,
      IOException {
    InetAddress addr = InetAddress.getLocalHost();
    System.out.println(addr);
    new Client(addr, "");
  }
}//ByteArrayOutputStream deposit = new java.io.ByteArrayOutputStream(4096);
//int k;
//while ((k = cis.read()) != -1) {
//deposit.write(buf, 0, k);
//}
//System.out.println("e...."+new String(buf));
//System.out.println("f...."+new String(buf).trim());
//if (new String(buf).trim().equals("READY")) {
//BufferedReader br = new BufferedReader(new FileReader(myfile));
//while ((s = br.readLine()) != null) {
//  temp += s;
//  temp += "\r\n";
//}
//os.write("OVER".getBytes());
//}