socket编程,服务器端抛出EOFException异常

[yqsshr]

import java.net.*;
import java.io.*;
//服务器端程序
public class Server 
{
	public static void main(String[] args) throws Exception
	{
		ServerSocket ss = new ServerSocket(6666);
		Socket s = ss.accept();
		
		DataInputStream dis = new DataInputStream(s.getInputStream());
		byte [] b = new byte[1024];
		int i = 0;
		while(dis.readByte() != -1) {
			b[i] = dis.readByte();
			i++ ;
		}
		FileOutputStream fos = new FileOutputStream("c:/ClientData.txt");
		fos.write(b);
		fos.flush();
		fos.close();
		dis.close();
		s.close();
	}
}
//客户端程序
import java.net.*;
import java.io.*;

public class Client 
{
	public static final String fileName = "c:" + File.separator + "TestClient.java";

	public static void main(String[] args) throws Exception
	{
		Socket s = new Socket("127.0.0.1",6666);
		DataOutputStream dos = new DataOutputStream(s.getOutputStream());
		FileInputStream fis = new FileInputStream(fileName);
		byte[] b = new byte[fis.available()];
		int len = fis.read(b);   //读取数据到数组b中，返回读到的字节数len
		dos.write(b, 0, len-1);
		dos.flush();
		fis.close();
		dos.close();	
	}
}

/*单独运行Server.java和Client.java都不会报错，说明socket编程是没有问题的，但当运行Server.java后再运行Client.java抛出如下错误：
Exception in thread "main" java.io.EOFException
        at java.io.DataInputStream.readByte(DataInputStream.java:250)
        at Server.main(Server.java:15)
*/

我知道这是读取文件取到末尾的错误，但不知道怎么回事，Server.java:15（b[i] = dis.readByte();
）怎么会错呢？已经判断了文件结尾的啊(while(dis.readByte() != -1))！希望达人不吝赐教~

[gordonkkk]

你怎么跳着读啊？

        while(dis.readByte() != -1) {
            b[i] = dis.readByte();
            i++ ;
        }

你while条件里读的那个Byte就不要了？
你在那里判断没到末尾，怎么能确定下一个Byte没到末尾呢？
而且你最起码套一个Buffer流吧，而且可以用read(byte[] b)这个方法读啊。你这样写效率太低。

[sunwei0325]

写文件用PrintWriter比较好

PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter("c:/ClientData.txt", true/*写入文件末尾*/)), true/*自动刷新*/);

[xiemk2005]

            ServerSocket ss = new ServerSocket(6666);
            Socket s = ss.accept();
            
            DataInputStream dis = new DataInputStream(s.getInputStream());
            FileOutputStream fos = new FileOutputStream("c:/ClientData.txt");
            byte [] b = new byte[1024];
            int i = 0;
            while((i = dis.read(b)) != -1) {
            	fos.write(b);
            }
//            fos.write(b);
            fos.flush();
            fos.close();
            dis.close();
            s.close();

[sunwei0325]

我根据自己以前的东西改了一下Server端，楼主可以参考一下

package test;

import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.BindException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;

public class Toyqsshr {
    boolean started = false;
    ServerSocket ss = null;

    public static void main(String[] args) {
        new Toyqsshr().start();
    }

    public void start() {
        try {
            ss = new ServerSocket(50000);
            started = true;
        } catch (BindException e) {
            System.out.println("端口使用中....");
            System.out.println("请关掉相关程序并重新运行服务器！");
            System.exit(0);
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            while (started) {
                Socket s = ss.accept();
                Save2File r = new Save2File(s);
                System.out.println(s.getInetAddress().toString() + " connected!");

                new Thread(r).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (!ss.isClosed()) {
                    ss.close();
                    ss = null;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    
    /**
     * 保存到文件
     */
    class Save2File implements Runnable {
        private Socket s = null;
        private DataInputStream dis = null;
        private PrintWriter pw = null;
        byte[] buffer = new byte[2000];
        String fileName = "c:/clientData.txt";

        public Save2File(Socket s) {
            this.s = s;
            try {
                dis = new DataInputStream(s.getInputStream());
                pw = new PrintWriter(new BufferedWriter(new FileWriter(fileName, true/* 写入文件末尾 */)), true/* 自动刷新 */);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void run() {
            try {
                while (true) {
                    int num = dis.read(buffer);
                    System.out.println("读取了" + num + "个字节");
                    for (int i = 0; i < num; i++) {
                        pw.printf("0x%02X ", buffer[i]);
                    }
                }
            } catch (UnknownHostException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    if (dis != null) {
                        dis.close();
                        dis = null;
                    }
                    if (pw != null) {
                        pw.close();
                        pw = null;
                    }
                    if (!s.isClosed()) {
                        s.close();
                        s = null;
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

[IniY0_0]

public final byte readByte() throws IOException {
int ch = in.read();
if (ch < 0)
throw new EOFException();
return (byte)(ch);
}
这是dis.readByte()调用的内部源码，楼主程序如果读到了末尾就肯定会抛出异常了

[diggywang]

这个异常可以不用理会

[yqsshr]

谢谢楼上的各位，都很有用！

[97095639]

楼主要注意异常处理

[yqsshr]

只是为了想实现功能，呵呵，就没关注了，谢谢提醒！

[「已注销」]

1.readByte()每次都会读出一个字节，因此不能条件里判断一次，后面再读一次
2.判断流的结尾是用 read()!=-1而不是readByte()!=-1

readByte()返回 -128~127的byte值，如果到达流的结尾则会抛出 EOFException
read()如果有内容时返回0~255,等效于readByte()&0xFF
无内容可读时返回 -1

[yqsshr]

谢谢各位，学了不少，结贴了。