基本思想是这样的，点击客户端的一个按钮可以通过服务器端连接数据库进行查询，并将结果显示在客户端的界面上。有一个双向的过程，客户端要发送数据（一个类），也要接收数据，服务器端也要接收数据处理好后再发回客户端。代码可以运行，但查询时服务器端抛出异常，说error by Connectjava.lang.ClassNotFoundException: hrclient.HREmployeeInfo

客户端：

//要查询的流
public class HREmployeeInfo extends Object implements java.io.Serializable
{
  int employeeCode;
  String employeeName;
  String employeeAge;
  String employeeSex;
  String employeeAddress;

}


void queryButton_actionPerformed(ActionEvent e) {

    HREmployeeInfo data = new HREmployeeInfo();
    HREmployeeInfo data1 = new HREmployeeInfo();
    data.employeeCode =Integer.parseInt(EmployeeCodeTextField.getText());

    try
    {
      Socket toServer;
      toServer = new Socket("localhost", 6666);
      ObjectOutputStream streamToServer = new ObjectOutputStream(toServer.getOutputStream());
      streamToServer.writeObject(data);

      ObjectInputStream streamFromServer = new ObjectInputStream(toServer.getInputStream());
      data1 =(HREmployeeInfo)streamFromServer.readObject();
      EmployeeNameTextField.setText(data1.employeeName);
      EmployeeAgeTextField.setText(data1.employeeAge);
      EmployeeSexTextField.setText(data1.employeeSex);
      EmployeeAddressTextField.setText(data1.employeeAddress);
      streamFromServer.close();
      streamToServer.close();

    }
    catch(Exception ea)
    {
      System.out.println("error by query" + ea);
    }
  }

服务器端：
……
try{
      server = new ServerSocket(6666);
       serverThread = new Thread(this);
       serverThread.start();
      }
      catch(Exception e)
     {
          System.out.println("Cannot start the thread" + e);
      }
……
 public void run()
    {
      try
      {
        while(true)
        {
          fromClient = server.accept();
          Connect con = new Connect(fromClient);
        }
      }
      catch(Exception ex5)
      {
        System.out.println("Cannot listen to the Client" + ex5);
      }
    }

……

public class Connect
{
  HREmployeeInfo data;
  ObjectInputStream streamFromClient;
  ObjectOutputStream streamToClient;

  public Connect(Socket inFromClient)
  {
    try
    {
     streamFromClient = new ObjectInputStream(inFromClient.getInputStream());
     data =  (HREmployeeInfo)streamFromClient.readObject();

     HREmployeeInfo data1 = new HREmployeeInfo();
     Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
     Connection cn = DriverManager.getConnection("jdbc:odbc:data", "sa", "");
     PreparedStatement stat = cn.prepareStatement("Select * from EmployeeInformation where employeeCode=?");
     stat.setInt(1,data.employeeCode);
     ResultSet result = stat.executeQuery();
     result.next();
      data1.employeeName = result.getString(2);
      data1.employeeAge = result.getString(3);
      data1.employeeSex = result.getString(4);
      data1.employeeAddress = result.getString(6);

      streamToClient =(ObjectOutputStream)inFromClient.getOutputStream();
      streamToClient.writeObject(data1);

      cn.close();
      streamFromClient.close();
      streamToClient.close();

    }
    catch(Exception ex6)
    {
      System.out.println("error by Connect" + ex6);
    }
  }
}

你调试一下，错误是在哪儿发生的。

我觉得应该是

找不到类：HREmployeeInfo