帮我看看 表格输出数据库的代码为何有异常

Question

         DefaultTableModel myData =  new DefaultTableModel();
        Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();            
            String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=student";
            String user="sa";
            String password=""; 
            Connection conn=DriverManager.getConnection(url,user,password);
           
            java.sql.Statement stmt=conn.createStatement();
            String sql="select * from class";
            ResultSet rs=stmt.executeQuery(sql);
            while(rs.next()){
                           String[] temparray = {
                            rs.getString("classid"),
                            rs.getString("gradeid"),
                            rs.getString("classname"),};
                            myData.addRow(temparray);
      }
   jTable1.setModel(myData);
   jTable1.setRowHeight(25);
    

Answer 1

异常如下,好象是数组益处的意思.?Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 0 >= 0
        at java.util.Vector.elementAt(Vector.java:427)
        at javax.swing.table.DefaultTableColumnModel.getColumn(DefaultTableColumnModel.java:277)
        at view.grade.initComponents(grade.java:168)
        at view.grade.<init>(grade.java:31)
        at view.appmain$action.actionPerformed(appmain.java:106)
        at java.awt.MenuItem.processActionEvent(MenuItem.java:627)
        at java.awt.MenuItem.processEvent(MenuItem.java:586)
        at java.awt.MenuComponent.dispatchEventImpl(MenuComponent.java:300)
        at java.awt.MenuComponent.dispatchEvent(MenuComponent.java:288)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:602)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

Answer 2

java.lang.ArrayIndexOutOfBoundsException: 0 
数据越界错误
数组下标连0都越界了，唯一的原因是数组的维数为0 
有两类数组初始化语句会导致这种情况发生 
int[] a=new int[0]; 
int[] a={}; 如果你的程序以前正常，现在变得不正常了，就只有一种情况了，那就是使用了int变量初始化数组，如 
int[] a=new int[i]; 
这个i是一个变量，当i>0程序正常；当i等于零时并试图去访问a[0]就会出现你看到的异常 解决这个问题先必须找到被数组维数被初始化为0的原因