delfrom.java

这个是学生考试系统,里面有完整的代码加数据库SQL server

package testsystem;

import java.awt.*;
import java.sql.*;
import javax.swing.*;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class DelFrom extends JFrame {
    private ImageIcon im1 = new ImageIcon("img\\red_forum.gif");
    public DelFrom() {
        try {
            jbInit();
        } catch (Exception exception) {
            exception.printStackTrace();
        }
    }

    private void jbInit() throws Exception {
        this.getContentPane().setBackground(new Color(226, 176, 226));
        this.setResizable(false);
        setTitle("删除用户！");
        getContentPane().setLayout(null);
        jButton1.setBounds(new Rectangle(142, 199, 110, 36));
        jButton1.setIcon(im1);
        jButton1.setText("删除");
        jButton1.addActionListener(new DelFrom_jButton1_actionAdapter(this));
        this.getContentPane().add(jButton1);
        jLabel2.setForeground(Color.red);
        jLabel2.setText("删除用户后如想恢复请在“添加用户”里添加！");
        jLabel2.setBounds(new Rectangle(65, 133, 252, 37));
        jLabel1.setText("请输入要删除的用户名：");
        jLabel1.setBounds(new Rectangle(125, 33, 132, 35));
        this.getContentPane().add(jLabel1);
        this.getContentPane().add(jt1);
        this.getContentPane().add(jLabel2);
        jt1.setBounds(new Rectangle(97, 81, 192, 34));
    }

    public static void main(String[] args) {
        DelFrom delfrom = new DelFrom();
    }

    JButton jButton1 = new JButton();
    JTextField jt1 = new JTextField();
    JLabel jLabel1 = new JLabel();
    JLabel jLabel2 = new JLabel();
    //删除用户功能
    public void jButton1_actionPerformed(ActionEvent e) {
          String Name=jt1.getText().trim();
          Connection con=null;
          Statement s1=null;
          ResultSet rs=null;
          if(Name.length()!=0)
          {
              try
              {
                  con=DBcon.link();
                  s1=con.createStatement();
                  rs=s1.executeQuery("select * from Login where Name='"+Name+"'");//查询表中Name里是否存在用户！
                  if(rs.next())
                  {
                      JOptionPane.showMessageDialog(null,"用户存在可以删除！");
                      s1.executeUpdate("delete from Login where Name='"+Name+"'"); //如果存在可以删除！
                      JOptionPane.showMessageDialog(null,"删除成功！");
                      int p=JOptionPane.showConfirmDialog(null,"您还要继续删除吗？","提示",JOptionPane.YES_NO_OPTION);
                      if(p!=0)
                      {
                          this.setVisible(false);
                      }
                      else
                      {
                          jt1.setText("");
                          jt1.requestFocus();
                          return;
                      }
                  }
                  else
                  {
                      JOptionPane.showMessageDialog(null,"没有这个用户，请重新输入！","提示",JOptionPane.ERROR_MESSAGE);
                      jt1.setText("");
                      jt1.requestFocus();
                  }
              }
              catch(SQLException ce)
              {
                  JOptionPane.showMessageDialog(null,ce.getMessage());
              }
          }
          else
          {
              JOptionPane.showMessageDialog(null,"用户名不能为空！","提示",JOptionPane.ERROR_MESSAGE);
          }
    }
}


class DelFrom_jButton1_actionAdapter implements ActionListener {
    private DelFrom adaptee;
    DelFrom_jButton1_actionAdapter(DelFrom adaptee) {
        this.adaptee = adaptee;
    }

    public void actionPerformed(ActionEvent e) {
        adaptee.jButton1_actionPerformed(e);
    }
}