Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException

[wuxinglong0216]

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;

public class TableTestM extends JFrame {
JTable jTable1;
JScrollPane jScrollPane1;

public TableTestM() {
jTable1 = new JTable(new MyTableModel(new ContSQL()));
jScrollPane1 = new JScrollPane(jTable1);
this.add(jScrollPane1);
this.pack();
this.setVisible(true);
}

public static void main(String[] args) {
new TableTestM();
}

}



import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;

import javax.swing.event.TableModelListener;
import javax.swing.table.TableModel;

public class MyTableModel implements TableModel {
private ContSQL contSql = null;
private static ResultSet rs = null;
private static Statement stmt = null;
private static Connection conn = null;
private int rowNum = 0;
private int colNum = 0;

public MyTableModel(ContSQL contSql) {
this.contSql = contSql;
try {
stmt = contSql.getStmt();
rs = stmt.executeQuery("select * from log_tab");
} catch (SQLException e) {
e.printStackTrace();
}
}

public void addTableModelListener(TableModelListener arg0) {
// TODO Auto-generated method stub
}

public Class<?> getColumnClass(int arg0) {
return null;
}

public int getColumnCount() {
ResultSetMetaData rsmd;
try {
rsmd = rs.getMetaData();
colNum = rsmd.getColumnCount()-1;
} catch (SQLException e) {
e.printStackTrace();
}
return colNum;

}

public String getColumnName(int i) {
ResultSetMetaData rsmd;
try {
rsmd = rs.getMetaData();
return rsmd.getColumnName(i + 1);
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}

public int getRowCount() {

try {
rs.last();
rowNum=rs.getRow()-1;
rs.beforeFirst();
return rowNum;
} catch (SQLException e) {
e.printStackTrace();
}
return -1;
}

public Object getValueAt(int row, int col) {
try {
if(row==0&&col==0){
rs.next();
}

if(row<rowNum&&col+1==colNum){
rs.next();
}
return rs.getString(col+1);

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

return null;
}

public boolean isCellEditable(int arg0, int arg1) {
return false;
}

public void removeTableModelListener(TableModelListener arg0) {
// TODO Auto-generated method stub

}

public void setValueAt(Object arg0, int arg1, int arg2) {
// TODO Auto-generated method stub

}


// public static void main(String[] args){
// MyTableModel ta = new MyTableModel(new ContSQL());
// System.out.println(ta.getRowCount()+"=====");
// System.out.println(ta.getColumnCount()+"=====");
//
// for(int i=0;i<=ta.rowNum;i++){
// for(int j=0;j<=ta.colNum;j++){
// System.out.println(ta.getValueAt(i, j)+"wocao");
// }
// }
//
// }


}

import java.sql.*;

public class ContSQL {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;

public ContSQL() {
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager
.getConnection("jdbc:mysql://localhost/fmm?user=root&password=521");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
// finally {
// if (conn != null) {
// try {
// conn.close();
// } catch (SQLException e) {
// }
// }
// if (conn != null) {
// try {
// conn.close();
// } catch (SQLException e) {
// }
// }
// if (conn != null) {
// try {
// conn.close();
// } catch (SQLException e) {
// }
// }
//
// }

}
/*public boolean isValidate(String username, String passwd) {
String sql = "select * from log_tab where username='" + username
+ "' and passwd='" + passwd + "'";

try {
rs = stmt.executeQuery(sql);
if (rs.next()) {
return true;
}
} catch (SQLException e) {
return false;
}
return false;
}*/


public Statement getStmt() throws SQLException {
return conn.createStatement();
}

}


create database fmm;
use fmm;
create table log_tab(
id int primary key auto_increment,
userName varchar(20) not null,
passwd varchar(9) not null
);

insert into log_tab(userName,passwd) values('zhangsan','wowowo');
insert into log_tab(userName,passwd) values('lisi','wowowo');
insert into log_tab(userName,passwd) values('wangwu','wowowo');
commit;

运行界面TableTestM时
总是报Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException异常
各位大虾帮忙解决下吧 谢谢了

[wuxinglong0216]

yiyang

[JavaAlpha]

哪一行出现的？贴一下详细异常信息。

[wuxinglong0216]

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.JTable.prepareRenderer(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paintCell(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paintCells(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paint(Unknown Source)
at javax.swing.plaf.ComponentUI.update(Unknown Source)
at javax.swing.JComponent.paintComponent(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JViewport.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paintWithOffscreenBuffer(Unknown Source)
at javax.swing.JComponent.paintDoubleBuffered(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at sun.awt.RepaintArea.paintComponent(Unknown Source)
at sun.awt.RepaintArea.paint(Unknown Source)
at sun.awt.windows.WComponentPeer.handleEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(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.pumpOneEventForHierarchy(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)

[k144521]

你导入JAVA.AWT.*;
JAVAX.SWING.*;
就可以了

[LYF_FLY]

我这会儿也是这样呀……咋办呢？明明在同学的电脑上是已经可以运行了的，回到我这儿就不行