socket：客户端接收不了服务器的消息

[jovial__]

我写的c/s，socket程序，客户端发送的消息，服务器可以接收到；但是服务器反馈的消息，客户端却接收不到，为什么？
我简化后的程序如下：

server端：
import java.net.*;
import java.sql.*;
import java.util.Hashtable;
import java.io.*;

public class logRegServer {
private static final long serialVersionUID = 1L;

ServerSocket serverSocket;
final int port=1444; //服务器和客户端监听的默认端口号

//该Hashtable用于记录链接服务器的客户端信息
private Hashtable<Socket,ObjectOutputStream> ht=
new Hashtable<Socket, ObjectOutputStream>();

public static void main(String[] args) throws IOException{
new logRegServer();
}

public logRegServer() throws IOException{
Socket clientSocket;

try{
//建立服务器套接字
serverSocket=new ServerSocket(port);

System.out.println("Log and Register Server started at: "+
serverSocket.getInetAddress().getLocalHost()+":"+
//InetAddress.getLocalHost()+":"+
serverSocket.getLocalPort());

while(true){
//服务器监听客户端的链接
clientSocket=serverSocket.accept();
System.out.println("Connection from: "+clientSocket);

//建立客户端的输出数据流
// DataOutputStream outData=new
// DataOutputStream(clientSocket.getOutputStream());
ObjectOutputStream outData=new ObjectOutputStream(clientSocket.getOutputStream());

//将客户端套接字和客户端对应的输出数据流绑定并添加到Hashtable中记录
ht.put(clientSocket, outData);

//新建立服务器线程，用于处理客户端的请求服务
Thread thread=new Thread(
new serverThread(clientSocket,ht));
thread.start(); //线程开始运行
}
}catch(IOException e){
e.printStackTrace();

}
}
}

class serverThread extends Thread implements Runnable{
private Socket clientSocket;
private Hashtable ht;

public serverThread(Socket clientSocket,Hashtable ht){
this.clientSocket=clientSocket;
this.ht=ht;
}

public void run(){
ObjectInputStream inData;
String logName=""; //用户登录名

try {
//建立客户端输入/输出数据流
inData=new ObjectInputStream(clientSocket.getInputStream());

while(true){
//接受客户端发送来的请求消息

//读取客户端发送来的消息标识
String inStrType=inData.readObject().toString();
System.out.println("消息类型："+inStrType);

//依据请求消息的起始部分，判断客户端请求服务的内容

if(inStrType.equals("Verify")){ //密码验证
logName=inData.readObject().toString();

try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
try {
Connection c=DriverManager.getConnection("jdbc:odbc:onlineJudge");
Statement s=c.createStatement();

ObjectOutputStream outData=new
ObjectOutputStream(clientSocket.getOutputStream());

//返回对应用户名的密码
ResultSet rs=s.executeQuery("select password from userInfoTable where userName='shimo'");

/**如果用户存在*/
if(rs.next()){
outData.writeObject(rs.getString("password"));
outData.flush();
}else{
outData.writeObject("UserNotExist@");
outData.flush();
}

outData.close();
//关闭数据库链接
s.close();
c.close();
}catch (SQLException se) { //未找到数据库，捕获异常
while (se != null) {
String SQLState = se.getSQLState();
String SQLMessage = se.getMessage();
System.out.println("Error = "+SQLState);
System.out.println(SQLMessage);
se = se.getNextException();
}
}
}catch(ClassNotFoundException e){ //未找到数据源驱动，捕获异常
e.printStackTrace();
}
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
System.out.println("end");
}
} //end run
}

class serverThread extends Thread implements Runnable{
private Socket clientSocket;
private Hashtable ht;

public serverThread(Socket clientSocket,Hashtable ht){
this.clientSocket=clientSocket;
this.ht=ht;
}

public void run(){
ObjectInputStream inData;
String logName=""; //用户登录名

try {
//建立客户端输入/输出数据流
inData=new ObjectInputStream(clientSocket.getInputStream());

while(true){
//接受客户端发送来的请求消息

//读取客户端发送来的消息标识
String inStrType=inData.readObject().toString();
System.out.println("消息类型："+inStrType);

//依据请求消息的起始部分，判断客户端请求服务的内容

if(inStrType.equals("Verify")){ //密码验证
logName=inData.readObject().toString();

try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
try {
Connection c=DriverManager.getConnection("jdbc:odbc:onlineJudge");
Statement s=c.createStatement();

ObjectOutputStream outData=new
ObjectOutputStream(clientSocket.getOutputStream());

//返回对应用户名的密码
ResultSet rs=s.executeQuery("select password from userInfoTable where userName='shimo'");

/**如果用户存在*/
if(rs.next()){
outData.writeObject(rs.getString("password"));
outData.flush();
}else{
outData.writeObject("UserNotExist@");
outData.flush();
}

outData.close();
//关闭数据库链接
s.close();
c.close();
}catch (SQLException se) { //未找到数据库，捕获异常
while (se != null) {
String SQLState = se.getSQLState();
String SQLMessage = se.getMessage();
System.out.println("Error = "+SQLState);
System.out.println(SQLMessage);
se = se.getNextException();
}
}
}catch(ClassNotFoundException e){ //未找到数据源驱动，捕获异常
e.printStackTrace();
}
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
System.out.println("end");
}
} //end run
}

客户端：
import javax.swing.*;
import java.io.*;
import java.net.*;

public class LogGUI {
static JFrame frame = new JFrame("ACM@ZZU");
private static final long serialVersionUID = 1L;
private static Socket clientSocket=null;
private static final String host="localhost";
private static final int port=1444;

public LogGUI() throws IOException {
try {
clientSocket = new Socket(InetAddress.getByName(host),port);
// clientSocket.setSoLinger(true, 20);
} catch (UnknownHostException e1) {
// TODO Auto-generated catch block
System.out.println("cannot connect the server!");
e1.printStackTrace();
} catch (IOException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}

ObjectInputStream inData=new ObjectInputStream(clientSocket.getInputStream());
ObjectOutputStream outData=new ObjectOutputStream(clientSocket.getOutputStream());

outData.writeObject("Verify");
outData.writeObject("shimo");

String s="";
try {
s = inData.readObject().toString();
System.out.println(s);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
System.out.println("receive from server ERROR!");
e.printStackTrace();
}
}

public static void main(String[] args) throws IOException {
new LogGUI();
}
}

谢谢大家！

[kevinchj]

自己先调试一下看看，哪一块出的问题……

[jovial__]

帖子，找不到编辑。发的时候忘了标识了。

错误为：在客户端接收消息的那个语句上。

客户端代码：LogGUI.java报的错误为：
Exception in thread "main" java.io.StreamCorruptedException: invalid type code: AC
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.readObject(Unknown Source)
at LogGUI.<init>(LogGUI.java:41)
at LogGUI.main(LogGUI.java:51)

[kokobox]

好多的代码.........看着有点....

[kokobox]

可能是你读取操作的文件已经损坏造成的，或是文件对象没有可序列实例化，lz重新序列实例化一下对象。

lz可以看下我给别人解决的帖子：

http://topic.csdn.net/u/20080405/17/80c2af21-0fa4-431a-bc7a-fec60f028f76.html

[Inhibitory]

有可能是服务器端发送消息后并没有强制清空缓冲区, 以至于发送的消息必须等到缓冲区满后才能一次性发送, 试着每发送一次消息, 清空一次缓冲区试试.

[linggan8]

把主要的问题写出来就好了！！

[jasonwhy]

程序有三个问题如下，帮你修改了一下：
1. 采用ObjectInputStream和ObjectoutputStream序列化必须实现Serializable接口，即implements Serializable
2. 在服务器端没有用outData.writeObject()方法
3. 当客户端发送数据到服务器后，服务器返回数据给客户端，由于客户端没有把监听放在while（ture）的循环中，服务器返回数据会出错，抛出java.net.SocketException: Connection reset异常！
由于你没有上传数据库，所有用注释把你的连接数据库的代码注释掉了，测试能够运行，仅供参考


客户端

import javax.swing.*;
import java.io.*;
import java.net.*;

public class LogGUI implements Serializable {
	// static JFrame frame = new JFrame("ACM@ZZU");
	private static final long serialVersionUID = 1L;
	private static Socket clientSocket = null;
	private static final String host = "localhost";
	private static final int port = 1444;

	public LogGUI() throws IOException {
		try {
			clientSocket = new Socket(InetAddress.getByName(host), port);
			// clientSocket.setSoLinger(true, 20);
		} catch (UnknownHostException e1) {
			// TODO Auto-generated catch block
			System.out.println("cannot connect the server!");
			e1.printStackTrace();
		} catch (IOException e2) {
			// TODO Auto-generated catch block
			e2.printStackTrace();
		}

		ObjectInputStream inData = new ObjectInputStream(clientSocket
				.getInputStream());
		ObjectOutputStream outData = new ObjectOutputStream(clientSocket
				.getOutputStream());

		outData.writeObject("Verify");
		outData.writeObject("shimo");

		String s = "";
		try {
			while (true) {
				s = inData.readObject().toString();
				System.out.println(s);
				s = "";
			}
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			System.out.println("receive from server ERROR!");
			e.printStackTrace();
		}
	}

	public static void main(String[] args) throws IOException {
		new LogGUI();
	}
}

服务器端

import java.net.*;
import java.sql.*;
import java.util.Hashtable;
import java.io.*;

public class logRegServer implements Serializable {
	private static final long serialVersionUID = 1L;
	ServerSocket serverSocket;
	final int port = 1444; // 服务器和客户端监听的默认端口号

	// 该Hashtable用于记录链接服务器的客户端信息
	private Hashtable<Socket, ObjectOutputStream> ht = new Hashtable<Socket, ObjectOutputStream>();

	public static void main(String[] args) throws IOException {
		new logRegServer();
	}

	public logRegServer() throws IOException {
		Socket clientSocket;

		try {
			// 建立服务器套接字
			serverSocket = new ServerSocket(port);

			System.out.println("Log and Register Server started at: "
					+ serverSocket.getInetAddress().getLocalHost() + ":" +
					// InetAddress.getLocalHost()+":"+
					serverSocket.getLocalPort());

			while (true) {
				// 服务器监听客户端的链接
				clientSocket = serverSocket.accept();
				System.out.println("Connection from: " + clientSocket);

				// 建立客户端的输出数据流
				// DataOutputStream outData=new
				// DataOutputStream(clientSocket.getOutputStream());
				ObjectOutputStream outData = new ObjectOutputStream(
						clientSocket.getOutputStream());
				outData.writeObject("发送返回给客户端的object对象放这里");

				// 将客户端套接字和客户端对应的输出数据流绑定并添加到Hashtable中记录
				ht.put(clientSocket, outData);

				// 新建立服务器线程，用于处理客户端的请求服务
				Thread thread = new Thread(new serverThread(clientSocket, ht));
				thread.start(); // 线程开始运行
			}
		} catch (IOException e) {
			e.printStackTrace();

		}
	}
}

class serverThread extends Thread implements Runnable, Serializable {
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private Socket clientSocket;
	private Hashtable ht;

	public serverThread(Socket clientSocket, Hashtable ht) {
		this.clientSocket = clientSocket;
		this.ht = ht;
	}

	public void run() {
		ObjectInputStream inData;
		String logName = ""; // 用户登录名

		try {
			// 建立客户端输入/输出数据流
			inData = new ObjectInputStream(clientSocket.getInputStream());

			while (true) {
				// 接受客户端发送来的请求消息

				// 读取客户端发送来的消息标识
				String inStrType = inData.readObject().toString();
				System.out.println("消息类型：" + inStrType);

				// 依据请求消息的起始部分，判断客户端请求服务的内容

				if (inStrType == "Verify") { // 密码验证
					logName = inData.readObject().toString();
					System.out.println("用户名：" + logName);

					/*
					 * try{ Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); try {
					 * Connection
					 * c=DriverManager.getConnection("jdbc:odbc:onlineJudge");
					 * Statement s=c.createStatement();
					 * 
					 * ObjectOutputStream outData=new
					 * ObjectOutputStream(clientSocket.getOutputStream());
					 * 
					 * //返回对应用户名的密码 ResultSet rs=s.executeQuery("select password
					 * from userInfoTable where userName='shimo'");
					 * 
					 *//** 如果用户存在 */
					/*
					 * if(rs.next()){
					 * outData.writeObject(rs.getString("password"));
					 * outData.flush(); }else{
					 * outData.writeObject("UserNotExist@"); outData.flush(); }
					 * 
					 * outData.close(); //关闭数据库链接 s.close(); c.close(); }catch
					 * (SQLException se) { //未找到数据库，捕获异常 while (se != null) {
					 * String SQLState = se.getSQLState(); String SQLMessage =
					 * se.getMessage(); System.out.println("Error = "+SQLState);
					 * System.out.println(SQLMessage); se =
					 * se.getNextException(); } } }catch(ClassNotFoundException
					 * e){ //未找到数据源驱动，捕获异常 e.printStackTrace(); }
					 */
				}
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block 
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block 
			e.printStackTrace();
		}

		finally {
			System.out.println("end");
		}
	} //end run 
}

[jovial__]

谢谢jasonwhy，kokobox等各位网友，尤其是jasonwhy的测试。

我的问题已经解决，但是我的方法却不同于jasonwhy，我的错误应该属于用同一个outPutStream构建了多个ObjectOutputStream导致序列化错误。

因为在服务器端接收客户端链接时，我用Hashtable保存了clientSocket和他的ObjectOutputStream对象，并传入了客户端的执行线程中。但是我在线程中发送消息时又实例化了ObjectOutputStream。

所以发送消息的时候会出现 [serialization stream header1] [object serialization form1] [serialization stream header2] [object serialization form2]...

我把Hashtable换成了Vector只保存clientSocket就ok了。

:-)，虽然紧接着出现了其他的错误，但我觉得这个错误应该是这样的原因吧。

关于序列化的，我参考了http://www.javaworld.com.tw/jute/post/view?bid=29&id=221962&sty=1；