在多线程服务器中使用ObjectOutputStream发送数组

我有一个带有两个以上按钮的客户端/服务器程序。当点击一个按钮时，它会向服务器发送一定的请求。根据请求，服务器必须返回一个字符串数组。我在服务器端使用ObjectOutputStream，在客户端使用ObjectInputStream。问题是ObjectInputStream不允许我多次调用readObject()方法。是否有更好的方式通过套接字连接发送数组。我使用PrintWriter将请求发送到服务器。我的服务器是多线程的。在多线程服务器中使用ObjectOutputStream发送数组

客户：

public FuncListener2() 
    { 

     butCheckOutSearchTitle.setEnabled(false); 
     String hostName = ""; 

     try { 
      hostName = InetAddress.getLocalHost().toString(); // to get the hostName for the exceptions 
      clientSocket = new Socket(InetAddress.getLocalHost(), 1211); 
      System.out.println(clientSocket.isConnected()); 
      printWriter = new PrintStream(clientSocket.getOutputStream()); 
      objIn = new ObjectInputStream(clientSocket.getInputStream()); 


      listeners(); 

      clientSocket.setKeepAlive(true); 
     } 
     catch (UnknownHostException e) 
     { 
      System.err.println("Don't know about host "+hostName); 
      e.printStackTrace(); 
     } 
     catch (IOException e) 
     { 
      System.err.println("Couldn't get I/O for the connection to the host "+hostName); 
      e.printStackTrace(); 
     } 
     catch(Exception ex) 
     { 
      System.err.println(ex.getMessage()); 
     } 
    } 

    public void listeners() 
    { 
     System.out.println("in listener"); 

     butCheckOutSearchSurname.addActionListener(new ActionListener() 
     { 
      public void actionPerformed(ActionEvent e) 
      { 
       try 
       { 

        System.out.println("surname search"); 
        int count = 0; 

        String [] array = null; 

        // the reason for the plus sign is to make sure the correct if statement is executed in the server 
        String query = "Select+ * FROM clientDet WHERE clientSurname = \'" + textCheckOutSearchSurname.getText() + "\'"; 
        printWriter.println(query); 

        obj = objIn.readObject(); 

        if(obj != null) 
        { 
         array = (String[])obj; 
        } 
        else 
        { 
         System.out.println("object empty"); 
        } 

        listCheckOutClients.setListData(array); 


       } 
       catch(Exception ex) 
       { 
        ex.printStackTrace(); 
       } 
      } 
     }); 

     listCheckOutClients.addListSelectionListener(new ListSelectionListener() 
     { 
      public void valueChanged(ListSelectionEvent e) 
      { 
       try 
       { 
        butCheckOutSearchTitle.setEnabled(true); 


       } 
       catch(Exception ex) 
       { 
        ex.printStackTrace(); 
       } 
      } 
     }); 


     butCheckOutSearchTitle.addActionListener(new ActionListener() 
     { 
      public void actionPerformed(ActionEvent e) 
      { 
       try 
       { 

        listCheckOutAvaliable.removeAll(); 
        String [] stringArray = null; 

        // the reason for the plus sign is to make sure the correct if statement is executed in the server 
        String query = "Select- * FROM stock WHERE stockTitle = \'" + textCheckOutSearchTitle.getText() + ",\' AND (stockStatus = \'available\' OR \'reserved\')"; 
        printWriter.println(query); 

        obj = objIn.readObject(); 

        stringArray = (String[])obj; 

        listCheckOutAvaliable.setListData(stringArray); 

        objIn = null; 


       } 
       catch(Exception ex) 
       { 
        ex.printStackTrace(); 
       } 
      } 
     }); 
     }

服务器：

public void run() 
    { 
     try 
     { 
      Class.forName("com.mysql.jdbc.Driver"); 
      conn = DriverManager.getConnection("jdbc:mysql://localhost/videostore", "root", "IronFire"); 

     } 
     catch(Exception ex) 
     { 
      ex.printStackTrace(); 
     } 
     try 
     { 
      System.out.println("Server"); 
      in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream())); 
      out = new PrintWriter(new OutputStreamWriter(clientSocket.getOutputStream())); 

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

      while (running) 
      { 
       //SELECT+ searching surname 
       //SELECT- searching titles 
       //[email protected] searching ####Num column 



       String command = in.readLine(); 
       System.out.println("Query: " + command); 
       if(command.substring(0, command.indexOf(" ")).equalsIgnoreCase("SELECT+")) 
       { 
        System.out.println("IN IF +"); // for test 
        surname(command); 
       } 
       if(command.substring(0, command.indexOf(" ")).equalsIgnoreCase("SELECT-")) 
       { 
        System.out.println("IN IF -"); // for test 
        title(command); 
       } 
       if (command.equalsIgnoreCase("quit")) 
       { 
        running = false; 
        System.out.print("Stopping client thread for client : " + clientID); 
       } 
       else 
       { 
        out.println(command); 
        out.flush(); 
       } 
      } 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
    } 
    public void surname(String query) 

    { 
     try 
     { 
      System.out.println("In Surname"); // for test 
      int count = 0; 
      int whileCounter = 0; 
      Statement state = conn.createStatement(); 

      res = state.executeQuery(query.replace("+", "")); 

      while(res.next()) 
      { 
       count++; 
      } 
      String [] stringResult = new String[count]; 
      res.beforeFirst(); 

      while(res.next()) 
      { 
       stringResult[whileCounter] = res.getString(1) +" "+ res.getString(2) +" " + res.getString(3) +" "+ res.getString(5) +" "+ res.getString(10) +" "+ res.getString(11) +""; 
       whileCounter++; 
      } 


      objOut.reset(); 
      objOut.writeUnshared(stringResult); 
      objOut.flush(); 



     } 
     catch(Exception ex) 
     { 
      ex.printStackTrace(); 
     } 

    } 
    public void title(String query) 
    { 
     try 
     { 
      int count = 0; 
      int whileCounter = 0; 

      Statement state = conn.createStatement(); 

      res = state.executeQuery(query.replace("-", "")); 
      System.out.println(query.replace("-", "")); 

      while(res.next()) 
      { 
       count++; 
      } 
      System.out.println(count); 
      String [] stringResult = new String[count]; 

      res.beforeFirst(); 

      while(res.next()) 
      { 
       stringResult[whileCounter] = res.getString(1) +" "+ res.getString(2) +" " + res.getString(3) +" "+ res.getString(5) +""; 
       whileCounter++; 
      } 

      for(int a = 0; a< stringResult.length; a++) 
      { 
       System.out.println(stringResult[a]); 
      } 

      objOut.reset(); 
      objOut.writeUnshared(stringResult); 
      objOut.flush(); 

     } 
     catch(Exception ex) 
     { 
      ex.printStackTrace(); 
     } 
    } 

}

的错误，这是唯一的错误，这是在客户端：

java.io.StreamCorruptedException: invalid type code: 53 
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1374) 
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:369) 
    at FuncListener2$3.actionPerformed(FuncListener2.java:197) 
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018) 
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341) 
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402) 
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) 
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252) 
    at java.awt.Component.processMouseEvent(Component.java:6505) 
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321) 
    at java.awt.Component.processEvent(Component.java:6270) 
    at java.awt.Container.processEvent(Container.java:2229) 
    at java.awt.Component.dispatchEventImpl(Component.java:4861) 
    at java.awt.Container.dispatchEventImpl(Container.java:2287) 
    at java.awt.Component.dispatchEvent(Component.java:4687) 
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832) 
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492) 
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422) 
    at java.awt.Container.dispatchEventImpl(Container.java:2273) 
    at java.awt.Window.dispatchEventImpl(Window.java:2713) 
    at java.awt.Component.dispatchEvent(Component.java:4687) 
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707) 
    at java.awt.EventQueue.access$000(EventQueue.java:101) 
    at java.awt.EventQueue$3.run(EventQueue.java:666) 
    at java.awt.EventQueue$3.run(EventQueue.java:664) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) 
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87) 
    at java.awt.EventQueue$4.run(EventQueue.java:680) 
    at java.awt.EventQueue$4.run(EventQueue.java:678) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) 
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:677) 
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211) 
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128) 
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117) 
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113) 
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105) 
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

来源

2012-03-17 IronFire

你可以调用的readObject（）可以随意多次。问题可能在于没有什么可读的时候它会阻止。你可以让这个阅读器使用后台线程，所以它的阻塞并不重要。

ObjectOutputStream假定对象是不可变的。如果更改一个对象，它不会再发送一次，而是发送一个对该对象的引用。

如果您希望每次在调用之间使用writeUnshared（）或使用reset（）时发送一个对象的新副本。

ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
ObjectOutputStream oos = new ObjectOutputStream(baos); 

List<String> strings = new ArrayList<String>(); 
strings.add("hello"); 

oos.writeUnshared(strings); 

strings.set(0, "world"); 

oos.writeUnshared(strings); 

oos.close(); 

ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(baos.toByteArray())); 

System.out.println(ois.readObject()); 
System.out.println(ois.readObject());

打印

[hello] 
[world]

来源

2012-03-17 14:04:39

我的程序工作的方式是，我必须按下一个按钮获取数组使用JList选择数组。那将启用另一个按钮。当我按下请求发送的按钮。但在我看来，服务器发送回客户端的数组与第一个数组冲突。 – IronFire 2012-03-17 14:22:27

我假设你正在改变你已经发送并重新发送的数组，但是你看到原始的两次？看我的编辑。 – 2012-03-17 14:25:30

我尝试使用writeUnshared（），但它给了我一个StreamCorruptedException。 – IronFire 2012-03-17 15:54:31

out = new PrintWriter(new OutputStreamWriter(clientSocket.getOutputStream())); 

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

您在插座上注册多个输出流，一些流可以使用缓冲，其他人可能得到尽可能多的字节有，或者在你不知道的情况下发送字节，导致接收端接收到正确顺序的字节，确保你没有得到se bugs，总是只在套接字上注册1个输出流，而不是更多。

来源

2013-03-11 13:15:53 Ferrybig

在多线程服务器中使用ObjectOutputStream发送数组

回答

相关问题