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求圣人道破玄机！

2013-10-24 
求高人道破玄机！！！package xiaomoimport java.sql.*import java.awt.BorderLayoutimport java.awt.Colo

求高人道破玄机！！！

package xiaomo;

import java.sql.*;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

class BuildButton extends JDialog{
static Connection con;
static PreparedStatement sql;

public BuildButton(MessageFace messageface,String title){

super(messageface,"Please finish writing .",true);

//利用箱式布局管理器设计Name栏mb
//Birthday标签
Box IDBox = Box.createHorizontalBox();
IDBox.add(Box.createHorizontalStrut(30));
JLabel IDLabel = new JLabel("ID:");
IDBox.add(IDLabel);

IDBox.add(Box.createHorizontalStrut(20));
final JTextField IDTextField = new JTextField(30);
IDBox.add(IDTextField);
IDBox.add(Box.createHorizontalStrut(200));

//Name标签
Box NameBox = Box.createHorizontalBox();
//container.add(NameBox,BorderLayout.NORTH);
NameBox.add(Box.createHorizontalStrut(30));
JLabel NameLabel = new JLabel("NAME:");
NameBox.add(NameLabel);


NameBox.add(Box.createHorizontalStrut(20));
final JTextField NameTextField = new JTextField(30);
NameBox.add(NameTextField);
NameBox.add(Box.createHorizontalStrut(200));

//Number标签
Box NumberBox = Box.createHorizontalBox();
NumberBox.add(Box.createHorizontalStrut(30));
JLabel NumberLabel = new JLabel("MobilePhone:");
NumberBox.add(NumberLabel);

NumberBox.add(Box.createHorizontalStrut(20));
final JTextField NumberTextField = new JTextField(30);
NumberBox.add(NumberTextField);
NumberBox.add(Box.createHorizontalStrut(200));

//QQNumber标签
Box QQNumberBox = Box.createHorizontalBox();
QQNumberBox.add(Box.createHorizontalStrut(30));
JLabel QQNumberLabel = new JLabel("QQNumber:");
QQNumberBox.add(QQNumberLabel);

QQNumberBox.add(Box.createHorizontalStrut(20));
final JTextField QQNumberTextField = new JTextField(30);
QQNumberBox.add(QQNumberTextField);
QQNumberBox.add(Box.createHorizontalStrut(200));

//Company标签
Box CompanyBox = Box.createHorizontalBox();
CompanyBox.add(Box.createHorizontalStrut(30));
JLabel CompanyLabel = new JLabel("Company:");
CompanyBox.add(CompanyLabel);

CompanyBox.add(Box.createHorizontalStrut(20));
final JTextField CompanyTextField = new JTextField(30);
CompanyBox.add(CompanyTextField);
CompanyBox.add(Box.createHorizontalStrut(200));

JButton b1 = new JButton("Finish");
JButton b2 = new JButton("Continue");

/*
 * 要想使得JPanel面板划分窗体空间，
 * 就必须使用网格布局管理器GridLayout和边界布局管理器BorderLayout
 * 而且在添加组件是要注意：
 * 先在container里对面板进行整体设置
 * 而后在个面板中设置GridLayout
 * 最后再添加到container中...
 */


//对container进行设置
Container container = getContentPane();
container.setLayout(new GridLayout(6,2,8,9));
setBounds(900, 50, 415, 220);
container.setBackground(Color.pink);

//对面板(容器的一种)进行设置
JPanel p1 = new JPanel(new GridLayout(1,2,8,9));//行，列，水平，垂直
p1.setBackground(Color.pink);
JPanel p2 = new JPanel(new GridLayout(1,2,8,9));
p2.setBackground(Color.pink);
JPanel p3 = new JPanel(new GridLayout(1,2,8,9));
p3.setBackground(Color.pink);
JPanel p4 = new JPanel(new GridLayout(1,2,8,9));
p4.setBackground(Color.pink);
JPanel p5 = new JPanel(new GridLayout(1,2,8,9));
p5.setBackground(Color.pink);
JPanel p6 = new JPanel(new GridLayout(1,2));

//将组件添加到面板，再添加到container
p1.add(IDBox,BorderLayout.NORTH);
p1.add(IDTextField);

p2.add(NameBox,BorderLayout.NORTH);
p2.add(NameTextField);

p3.add(NumberBox,BorderLayout.NORTH);
p3.add(NumberTextField);

p4.add(QQNumberBox,BorderLayout.NORTH);
p4.add(QQNumberTextField);

p5.add(CompanyBox,BorderLayout.NORTH);
p5.add(CompanyTextField);

p6.add(b1,BorderLayout.NORTH);
p6.add(b2,BorderLayout.NORTH);

container.add(p1);
container.add(p2);
container.add(p3);
container.add(p4);
container.add(p5);
container.add(p6);

b1.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent arg0){



try {

sql = con.prepareStatement("insert into xiaomotable" + "values(?,?,?,?,?)");
sql.setString(1, IDTextField.getText());
sql.setString(2, NameTextField.getText()); 
 
sql.setString(3, NumberTextField.getText());
sql.setString(4, QQNumberTextField.getText());
sql.setString(5, CompanyTextField.getText());

} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

});
}
}




此代码的错误反馈：
引用
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at xiaomo.BuildButton$1.actionPerformed(BuildButton.java:149)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$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.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(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.pumpEventsForFilter(Unknown Source)
at java.awt.WaitDispatchSupport$2.run(Unknown Source)
at java.awt.WaitDispatchSupport$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.awt.WaitDispatchSupport.enter(Unknown Source)
at java.awt.Dialog.show(Unknown Source)
at java.awt.Component.show(Unknown Source)
at java.awt.Component.setVisible(Unknown Source)
at java.awt.Window.setVisible(Unknown Source)
at java.awt.Dialog.setVisible(Unknown Source)
at xiaomo.MessageFace$1.actionPerformed(MessageFace.java:70)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$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.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(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)


[解决办法]
  你都这个直接调用 con 肯定NULL 的 。你写个方法获取连接，ruturn 一个 con 连接 。用的时候先赋值。

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