调用方式往table里插入数据受阻 救命

调用模式往table里插入数据受阻 救命
运行后错误如下： 
java.lang.ClassCastException: javax.swing.JTable$1 cannot be cast to javax.swing.table.DefaultTableModel at mhs.RSS.actionPerformed(RSS.java:90) 
  at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) 
  at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) 
  at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) 
  at javax.swing.DefaultButtonModel.setPressed(Unknown Source) 
  at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source) 
  at java.awt.Component.processMouseEvent(Unknown Source) 
  at javax.swing.JComponent.processMouseEvent(Unknown Source) 
  at java.awt.Component.processEvent(Unknown Source) 
  at java.awt.Container.processEvent(Unknown Source) 
  at java.awt.Component.dispatchEventImpl(Unknown Source) 
  at java.awt.Container.dispatchEventImpl(Unknown Source) 
  at java.awt.Component.dispatchEvent(Unknown Source) 
  at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) 
  at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) 
  at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) 
  at java.awt.Container.dispatchEventImpl(Unknown Source) 
  at java.awt.Window.dispatchEventImpl(Unknown Source) 
  at java.awt.Component.dispatchEvent(Unknown Source) 
  at java.awt.EventQueue.dispatchEvent(Unknown Source) 
  at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) 
  at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) 
  at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) 
  at java.awt.EventDispatchThread.pumpEvents(Unknown Source) 
  at java.awt.EventDispatchThread.pumpEvents(Unknown Source) 
  at java.awt.EventDispatchThread.run(Unknown Source) 
 
程序代码如下： 
import javax.swing.*; 
import javax.swing.event.*; 
import javax.swing.table.*; 
import java.util.*; 
import java.awt.*; 
import java.awt.event.*; 
 
import java.net.URL;  
import java.util.List;  
import java.util.*; 
import java.text.SimpleDateFormat; 
 
import com.sun.syndication.feed.synd.SyndCategory;  
import com.sun.syndication.feed.synd.SyndContent;  
import com.sun.syndication.feed.synd.SyndEnclosure;  
import com.sun.syndication.feed.synd.SyndEntry;  
import com.sun.syndication.feed.synd.SyndFeed;  
import com.sun.syndication.io.SyndFeedInput;  
import com.sun.syndication.io.XmlReader;  
 
 
public class RSS extends Frame implements ActionListener 
{ 
  JLabel RSS = new JLabel("RSS:"); 
  JTextField URL = new JTextField(); 
  JButton JB= new JButton("确认"); 
  Object[][]tablevalue = new Object[20][4]; 
  String []name={"标题","作者","时间","摘要"}; 
  JTable table = new JTable(tablevalue,name); 
   
  public RSS() 
  { 
  this.setTitle("欢迎使用RSS阅读器"); 
 
  RSS.setBounds(100,570,60,60); 
  this.add(RSS); 
  URL.setBounds(170,570,400,50); 
  this.add(URL); 
  JB.setBounds(620,570,70,50); 
  this.add(JB); 

  JB.addActionListener(this); 
   
   
   
   
   
  table.setBounds(40,150,720,500); 
  TableColumn Column0 = table.getColumnModel().getColumn(0);  
  Column0.setPreferredWidth(80); 
  TableColumn Column1 = table.getColumnModel().getColumn(1);  
  Column1.setPreferredWidth(60); 
  TableColumn Column2 = table.getColumnModel().getColumn(2);  
  Column2.setPreferredWidth(60); 
  TableColumn Column3 = table.getColumnModel().getColumn(3);  
  Column3.setPreferredWidth(400); 
  table.setRowHeight(25);  
   
  this.add(new JScrollPane(table)); 
  this.setBounds(100,200,800,700); 
  this.setVisible(true); 
  addWindowListener(new WindowAdapter() 
  {public void windowClosing(WindowEvent e) 
  { 
  System.exit(0); 
  } 
  }); 
  } 
   
   
  public static void main(String args[]) 
  { 
  new RSS(); 
  } 
   
   
  @Override 
  public void actionPerformed(ActionEvent e)  
  { 
  // TODO Auto-generated method stub 
  if(e.getSource()==JB) 
  {  
  try {  
  //URL url = new URL(RSS.getText()); 
  URL.setText("http://rss.sina.com.cn/ent/hot_roll.xml"); 
  URL url = new URL(URL.getText()); 
  XmlReader reader = new XmlReader(url);  
  SyndFeedInput input = new SyndFeedInput(); 
  DefaultTableModel model = (DefaultTableModel)table.getModel(); //就是这句出问题了，大牛，怎么改啊 SyndFeed feed = input.build(reader);  
  List entries = feed.getEntries();  
   
  for (int i = 0; i < entries.size(); i++)  
  { String[] arr=new String[4];  
  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
 
  SyndEntry entry = (SyndEntry) entries.get(i);  
  arr[0]=entry.getTitle();  
  arr[1]=entry.getAuthor(); 
  arr[2]=sdf.format(entry.getPublishedDate()); 
 
  SyndContent description = entry.getDescription();  
  arr[3]=description.getValue(); 
  model.addRow(arr);  
   
  } 
  table.invalidate();  
  } 
  catch (Exception error)  
  {  
  error.printStackTrace();  
  } 
  } 
 
  } 
} 


[解决办法]
类型转换出错了，不是DefaultTableModel类型的