连接不上数据库，大神帮忙看看代码哪儿错了。

package xues;

import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Vector;
 
import javax.swing.*;
import javax.swing.table.JTableHeader;
 
public class Home extends JFrame implements ActionListener{
      JScrollPane scpDemo;
       JFrame  Add;
     JTableHeader jth;
     JTable tabDemo;
     JTextField text,AddName,AddNumber,AddSex,AddAge,AddPost,AddWage,AddJop;
     JLabel name,number,age,sex,wage,post,jop;
     JButton anShow,anSet,anSelsct,anClear,anAdd,Addyes,Addno;
     String SQLname,SQLsex,SQLpost,SQLjop;
     String a[]={SQLname,SQLsex,SQLpost,SQLjop};
     int SQLnumber,SQLage,SQLwage;
     int b[]={SQLnumber,SQLage,SQLwage};
     
     
    public Home(){  
        super("学生管理系统");
        this.setSize(400,500);
        this.setLayout(null);
        this.setLocation(400,100);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
        this.setResizable(false);//钉死
        this.text=new JTextField();
        this.text.setBounds(10, 20,200, 25);
        this.anSelsct=new JButton("查询");
        this.anSelsct.setBounds(230,20,70,25);
        this.anShow=new JButton("刷新");
        this.anShow.setBounds(310,20,70,25);
        this.anAdd=new JButton("添加");
        this.anAdd.setBounds(20,435,70,25);
        this.anSet=new JButton("修改");
        this.anSet.setBounds(100,435,70,25);
        this.anClear=new JButton("删除");
        this.anClear.setBounds(180,435,70,25);
        this.scpDemo = new JScrollPane();
        this.scpDemo.setBounds(10,50,365,380);
        AddName=new JTextField();
        AddNumber=new JTextField();
        AddAge=new JTextField();
        AddSex=new JTextField();
        AddPost=new JTextField();
        AddWage=new JTextField();
        AddJop=new JTextField();
         
        name=new JLabel("姓名");
        number=new JLabel("学号");
        age=new JLabel("年龄");
        sex=new JLabel("性别");
        post=new JLabel("职位");
        wage=new JLabel("工资");
        jop=new JLabel("地点");
         
         
        Addyes=new JButton("确定");
        Addno=new JButton("取消");
         
         
         
        //添加窗口的创建
          Add=new  JFrame();                    
        Add.setTitle("添加");
        Add.setSize(350,400);
        Add.setLocation(100, 260);
        Add.setLayout(new GridLayout(8,2));
        Add.add(number);Add.add(AddNumber);
        Add.add(name);Add.add(AddName);
        Add.add(sex);Add.add(AddSex);
        Add.add(age);Add.add(AddAge);
        Add.add(post);Add.add(AddPost);
        Add.add(wage);Add.add(AddWage);
        Add.add(jop);Add.add(AddJop);
        Add.add(Addyes); Add.add(Addno);
         
        
         
        Addyes.addActionListener(this);
        Addno.addActionListener(this);
        anAdd.addActionListener(this);
        anShow.addActionListener(this);
        anSet.addActionListener(this);
        anSelsct.addActionListener(this);
        anClear.addActionListener(this);
         
         
 
         
            
     
        this.scpDemo.getViewport().add(tabDemo); 
         
         add(this.scpDemo);
         add(this.text);
         add(this.anSelsct);
         add(this.anShow);     
         add(this.anAdd);
         add(this.anSet);
         add(this.anClear);
       
          
       
          
         this.remove(this);//刷新
         this.repaint();
         
         try{
            // 获得连接
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
         Connection conn = DriverManager.getConnection("jdbc:sqlserver://localhost:1433; DatabaseName=people","sa","123456");
         // 建立查询条件
         
         
          
        String sql="select * from nature";
 
          
       
         PreparedStatement pstm = conn.prepareStatement(sql);
         // 执行查询
         ResultSet rs = pstm.executeQuery();
         // 计算有多少条记录
         int count = 0;
         while(rs.next()){
         count++;
         }
         rs = pstm.executeQuery();
         // 将查询获得的记录数据，转换成适合生成JTable的数据形式
         Object[][] info = new Object[count][7];
         count = 0;
         while(rs.next()){
             
         info[count][0] = Integer.valueOf( rs.getInt("number"));
         info[count][1] = rs.getString("name");
         info[count][2] = rs.getString("sex");
         info[count][3] = Integer.valueOf( rs.getInt("age") );
         info[count][4] = rs.getString("post");
         info[count][5] = Integer.valueOf( rs.getInt("wage"));
         info[count][6] = rs.getString("jop");
         
         count++;
          
        
         }
         // 定义表头
         String[] title = {"学号","姓名","性别","年龄","职位","工资","地点"};
         // 创建JTable
         this.tabDemo = new JTable(info,title);
         // 显示表头
         this.jth = this.tabDemo.getTableHeader();
         // 将JTable加入到带滚动条的面板中
         this.scpDemo.getViewport().add(tabDemo); 
         }catch(ClassNotFoundException cnfe){
         JOptionPane.showMessageDialog(null,"数据源错误","错误",JOptionPane.ERROR_MESSAGE);
         }catch(SQLException sqle){
         JOptionPane.showMessageDialog(null,"数据操作错误","错误",JOptionPane.ERROR_MESSAGE);
         }
          
    }
      chaxun re=new chaxun();
    @Override
    public void actionPerformed(ActionEvent e) {
         
         
        if(e.getSource()==(anAdd)){
            Add a=new Add(this,"添加学生信息",true);
            re=new chaxun();
            tabDemo.setModel(re);
         
             
        }
     
                        
        else if(e.getSource()==(anSelsct)){
             
            String name=this.text.getText().trim();
            String sql="select * from nature where name='"+name+"'";
            chaxun aa=new chaxun(sql);
             
            tabDemo.setModel(aa);
                         
        }
        else if(e.getSource()==anShow){
             
            tabDemo.setModel(re);
        }
        else if(e.getSource()==(anClear)){
            int i=this.tabDemo.getSelectedRow();
            clear aa=new clear(i);
            re=new chaxun();
            tabDemo.setModel(re);
                 
        }
        else if(e.getSource()==anSet){
             
            int j=this.tabDemo.getSelectedRow();
             
            revise a=new revise(this,"修改学生信息",true,re,j);
             
            re=new chaxun();
            tabDemo.setModel(re);
        }
         
    }
     
     
    }
    

7 个解决方案

#1

有没有报错信息

#2

报错信息 ？

#3

就直接显示连接数据源错误，点击查询会显示
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at ui.Home.actionPerformed(Home.java:192)
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$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.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)

#4

引用 3 楼 ppl007110 的回复:

就直接显示连接数据源错误，点击查询会显示
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at ui.Home.actionPerformed(Home.java:192)
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$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.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)

这是数据库错误吗？

#5

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at ui.Home.actionPerformed(Home.java:192)

#6

引用 5 楼 Q80470101 的回复:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at ui.Home.actionPerformed(Home.java:192)

空指针了，检查一下哪为空？

#7

还是不明白啊。。。。