我有一个带有两个以上按钮的客户端/服务器程序。单击按钮时，它会向服务器发送特定请求。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。是否有更好的方法跨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。
客户端：
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
//SELECT@ 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();
}
}
}
错误这是唯一的错误，它在客户端：
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)
答案 0 :(得分：0)
您可以根据需要随时调用readObject（）。问题可能是当没有任何东西要读时它会阻塞。你可以让这个读者使用后台线程，因此它的阻塞无关紧要。
ObjectOutputStream假定对象是不可变的。如果你更改了一个对象，它就不会再发送它，而是发送一个对该对象的引用。
如果你想在每次使用writeUnshared（）或在调用之间使用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]
答案 1 :(得分：0)
out = new PrintWriter(new OutputStreamWriter(clientSocket.getOutputStream())); objOut= new ObjectOutputStream(clientSocket.getOutputStream());
您正在套接字上注册多个输出流，某些流可能使用缓冲，其他流可能获得尽可能多的字节，或者在您不知情的情况下发送字节，导致接收方接收到正确顺序的字节，确保你没有得到这些错误，总是只在套接字上注册1个输出流，而不是更多。