中国地质大学北京信息管理与信息系统——Java程序设计第四次上机part2(查询后，输入到滚动面板里显示)

//在通过上个作业的折磨后，这个课后作业做得比较顺畅 （ps.数据库的建立最好和我的一样，防止出现报错）
package Nobody_care;

import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import javax.swing.AbstractAction;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.Jframe;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.Jtextarea;
import javax.swing.JTextField;
import javax.swing.WindowConstants;

public class homework_last {
	
	static int flag=0;// 0姓名，1学号；
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Jframe jf=new Jframe();
		JPanel jp=new JPanel();
		Jtextarea jt=new Jtextarea(300,200);
		JScrollPane js=new JScrollPane(jt);
		JRadioButton jr1=new JRadioButton("姓名");
		JRadioButton jr2=new JRadioButton("学号");
		ButtonGroup g=new ButtonGroup(); g.add(jr1);g.add(jr2);
		JLabel jl=new JLabel("输入检索条件");
		JTextField jt1=new JTextField();
		JButton jb1=new JButton("查询"),jb2=new JButton("重置");
		jf.setLayout(new GridLayout(2,1));
		jp.setLayout(new GridLayout(3,2));
		jr1.addActionListener(new AbstractAction() {
			
			@Override
			public void actionPerformed(ActionEvent e) {
				// TODO Auto-generated method stub
				flag=0;
			}
		});
		jr2.addActionListener(new AbstractAction() {
			
			@Override
			public void actionPerformed(ActionEvent e) {
				// TODO Auto-generated method stub
				flag=1;
			}
		});
		jb1.addActionListener(new AbstractAction() {
			
			@Override
			public void actionPerformed(ActionEvent e) {
				// TODO Auto-generated method stub
				try {
					Class.forName("com.mysql.cj.jdbc.Driver");
					String url = "jdbc:mysql://localhost:3306/student?useSSL=false&serverTimezone=UTC";
					String name = "root";
					String password = "123456";
					Connection d=  DriverManager.getConnection(url,name,password);
					Statement st=d.createStatement();
					String s0="学生姓名=",s1="学号=";
					String s="select *from students where ";
					ResultSet re=null;
					if(flag==0) {
						s+=s0+"'"+jt1.getText()+"'";
						re=(ResultSet) st.executeQuery(s);
					}else {
						s+=s1+jt1.getText();
						re=st.executeQuery(s);
					}
					String ans="";
					while(((ResultSet) re).next()) {
						ans+="学号:"+((ResultSet) re).getInt("学号")+" "+"姓名:"+((ResultSet) re).getString("学生姓名")+" "+"课程:"+((ResultSet) re).getString("课程名称")+" "+"成绩:"+((ResultSet) re).getDouble("课程成绩")+"n";
					}
					jt.setText(ans);
				} catch (Exception e2) {
					// TODO: handle exception
				}
			}
		});
		jb2.addActionListener(new AbstractAction() {
			
			@Override
			public void actionPerformed(ActionEvent e) {
				// TODO Auto-generated method stub
				jt.setText("");jt1.setText("");
			}
		});
		
		jp.add(jr1);jp.add(jr2);jp.add(jl);jp.add(jt1);jp.add(jb1);jp.add(jb2);
		
		jf.add(js);jf.add(jp);
		jf.setBounds(500,250,300,300);
		jf.setVisible(true);
		jf.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
		
	}

}