Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Studentguanli.actionPerformed(Studentguanli.java:111)
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)
页面代码：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.*;
public class Studentguanli extends JPanel implements ActionListener {
Hashtable 基本信息表 = null;
JTextField 学号, 姓名, 政治面貌, 家庭住址, 出生日期,电话号码,宿舍号码;
JRadioButton 男, 女;
Student 学生 = null;
ButtonGroup group = null;
JButton 录入, 重置;
FileInputStream inOne = null;
ObjectInputStream inTwo = null;
FileOutputStream outOne = null;
ObjectOutputStream outTwo = null;
File file = null;
public Studentguanli(File file) {
this.file = file;
学号 = new JTextField(10);
姓名 = new JTextField(10);
政治面貌 = new JTextField(10);
家庭住址 = new JTextField(10);
出生日期 = new JTextField(10);
电话号码 = new JTextField(10);
宿舍号码 = new JTextField(10);
group = new ButtonGroup();
男 = new JRadioButton("男", true);
女 = new JRadioButton("女", false);
group.add(男);
group.add(女);
录入 = new JButton("录入");
重置 = new JButton("重置");
录入.addActionListener(this);
重置.addActionListener(this);
Box box1 = Box.createHorizontalBox();
box1.add(new JLabel("学号:", JLabel.CENTER));
box1.add(学号);
Box box2 = Box.createHorizontalBox();
box2.add(new JLabel("姓名:", JLabel.CENTER));
box2.add(姓名);
Box box3 = Box.createHorizontalBox();
box3.add(new JLabel("性别:", JLabel.CENTER));
box3.add(男);
box3.add(女);
Box box4 = Box.createHorizontalBox();
box4.add(new JLabel("政治面貌:", JLabel.CENTER));
box4.add(政治面貌);
Box box5 = Box.createHorizontalBox();
box5.add(new JLabel("家庭住址:", JLabel.CENTER));
box5.add(家庭住址);
Box box6 = Box.createHorizontalBox();
box6.add(new JLabel("出生日期:", JLabel.CENTER));
box6.add(出生日期);
Box box7 = Box.createHorizontalBox();
box7.add(new JLabel("电话号码:", JLabel.CENTER));
box7.add(电话号码);
Box box8 = Box.createHorizontalBox();
box8.add(new JLabel("宿舍号码:", JLabel.CENTER));
box8.add(宿舍号码);
Box boxH = Box.createVerticalBox();
boxH.add(box1);
boxH.add(box2);
boxH.add(box3);
boxH.add(box4);
boxH.add(box5);
boxH.add(box6);
boxH.add(box7);
boxH.add(box8);
boxH.add(Box.createVerticalGlue());
JPanel pCenter = new JPanel();
pCenter.add(boxH);
setLayout(new BorderLayout());
add(pCenter, BorderLayout.CENTER);
JPanel pSouth = new JPanel();
pSouth.add(录入);
pSouth.add(重置);
add(pSouth, BorderLayout.SOUTH);
validate();
}
public void actionPerformed(ActionEvent e) { //学生信息录入
if (e.getSource() == 录入) {
String number = "";
number = 学号.getText();
if (number.length() > 0) {
try {
inOne = new FileInputStream(file);
inTwo = new ObjectInputStream(inOne);
基本信息表 = (Hashtable) inTwo.readObject();
inOne.close();
inTwo.close();
} catch (Exception ee) {
}
if (基本信息表.containsKey(number)) {
String warning = "该生基本信息已存在,请到修改页面修改!";
JOptionPane.showMessageDialog(this, warning, "警告",
JOptionPane.WARNING_MESSAGE);
} else {
String m = "基本信息将被录入!";
int ok = JOptionPane.showConfirmDialog(this, m, "确认",
JOptionPane.YES_NO_OPTION,
JOptionPane.INFORMATION_MESSAGE);
if (ok == JOptionPane.YES_OPTION) {
String name = 姓名.getText();
String zhengzhi = 政治面貌.getText();
String dizhi = 家庭住址.getText();
String borth = 出生日期.getText();
String phone = 电话号码.getText();
String sushe = 宿舍号码.getText();
String sex = null;
if (男.isSelected()) {
sex = 男.getText();
} else {
sex = 女.getText();
}
学生 = new Student();
学生.setNumber(number);
学生.setName(name);
学生.setzhengzhi(zhengzhi);
学生.setdizhi(dizhi);
学生.setBorth(borth);
学生.setSex(sex);
学生.setphone(phone);
学生.setsushe(sushe);
try {
outOne = new FileOutputStream(file);
outTwo = new ObjectOutputStream(outOne);
基本信息表.put(number, 学生);
outTwo.writeObject(基本信息表);
outTwo.close();
outOne.close();
学号.setText(null);
姓名.setText(null);
政治面貌.setText(null);
家庭住址.setText(null);
出生日期.setText(null);
电话号码.setText(null);
宿舍号码.setText(null);
} catch (Exception ee) {
System.out.println(ee);
}
}
}
} else {
String warning = "必须要输入学号!";
JOptionPane.showMessageDialog(this, warning, "警告",
JOptionPane.WARNING_MESSAGE);
}
}
if (e.getSource() == 重置) {
学号.setText(null);
姓名.setText(null);
政治面貌.setText(null);
家庭住址.setText(null);
出生日期.setText(null);
电话号码.setText(null);
宿舍号码.setText(null);
}
}
报了空指针错误，在Studentguanli.java 第111行
怎么改啊？改好了吗？