实验六 Java期中考试

1、期中考试：二、package Exextra_2;import java.util.*;public class Test public static void main(String args) int a=new int10;Scanner scan=new Scanner(System.in);for(int i=0;i<10;i+)ai=scan.nextInt();int max=a0;int min=a0;for(int i=0;i<10;i+)if(ai>max)max=ai;for(int i=0;i<10;i+)if(ai<min)min=ai;

2、System.out.println("max="+max+" min="+min);三、package Exextra_3;public class Point private int x,y;private double s;public Point()public Point(int x,int y)this.x=x;this.y=y;public int getX()return x;public void setX(int x)this.x=x;public int getY()return y;public void setY(int y)t

3、his.y=y;public String toString()return "("+x+","+y+")"public double distance(Point p1,Point p2)int x1=p1.getX();int y1=p1.getY();int x2=p2.getX();int y2=p2.getY();s=Math.sqrt(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);return s;package Exextra_3;public class Test public static void

4、main(String args) Point p1=new Point(4,5);Point p2=new Point(2,1);double s=p2.distance(p1,p2);System.out.println(p1.toString();System.out.println(p2.toString();System.out.println(s);四、package Exextra_4;public interface Shapepublic abstract double area();package Exextra_4;public class MyCircle implem

5、ents Shapeprivate double r;public MyCircle(double r)this.r=r;public double area()return Math.PI*r*r;public String toString()return "circle: r="+r+" area="+this.area();package Exextra_4;public class MyRectangle implements Shape private double w,h;public MyRectangle(double w,double

6、 h)this.w=w;this.h=h;public double area()return w*h;public String toString()return "Rectangle: width="+w+" "+"height="+h+" area="+this.area();package Exextra_4;public class Test public static void main(String args) Shape t1=new MyRectangle(10,5);System.out.pri

7、ntln(t1.toString();Shape t2=new MyCircle(3);System.out.println(t2.toString();五、package Exextra_5;import javax.swing.*;import java.awt.*;import java.awt.event.*;public class MyFrm extends JFrame implements ActionListenerint m=0;JButton btn1=new JButton("点我");JButton btn2=new JButton("清

8、零");JLabel lb=new JLabel("共点击了0次");public MyFrm()JPanel jp=(JPanel)this.getContentPane();jp.setLayout(new FlowLayout();jp.add(btn1);jp.add(btn2);jp.add(lb);btn1.addActionListener(this);btn2.addActionListener(this);this.setTitle("ButtonDemol");public void actionPerformed(Acti

9、onEvent e)if(e.getSource()=btn1)m=m+1;lb.setText("共点击了"+m+"次");if(e.getSource()=btn2)m=0;lb.setText("共点击了"+m+"次");public static void main(String args)MyFrm frm=new MyFrm();frm.setSize(400,100);frm.setVisible(true);数据库调试：package mydb;import java.sql.*;public cl

10、ass StudentDao private String driver = "sun.jdbc.odbc.JdbcOdbcDriver"private String url = "jdbc:odbc:mydb"private void executeUpdate(String sql) try Class.forName(driver);Connection con = DriverManager.getConnection(url);Statement cmd = con.createStatement();cmd.executeUpdate(sql

11、);con.close(); catch (Exception ex) ex.printStackTrace();public void addStudent(String sno, String sname, String major, int zg) String sql = "insert into student values('" + sno + "','" + sname+ "','" + major + "'," + zg + ")"

12、executeUpdate(sql);public void deleteStudentBySno(String sno) String sql = "delete from student where sno='" + sno + "'"executeUpdate(sql);public String queryStudents() String rows = null;try Class.forName(driver);Connection con = DriverManager.getConnection(url);Statemen

13、t cmd = con.createStatement();String sql = "select count(*) from student"ResultSet rs = cmd.executeQuery(sql);rs.next();int rowcount = rs.getInt(1);rows = new Stringrowcount4;sql = "select * from student"rs = cmd.executeQuery(sql);rowcount = 0;while (rs.next() for (int i = 1; i &

14、lt;= 4; i+)rowsrowcounti - 1 = rs.getString(i);rowcount+;con.close(); catch (Exception ex) ex.printStackTrace();return rows;package mydb;import javax.swing.*;import java.awt.*;import java.awt.event.*;public class MainFrm extends JFrame private void initMenu() JMenuBar bar = new JMenuBar();JMenu m1 =

15、 new JMenu("学生管理");JMenu m2 = new JMenu("课程管理");JMenuItem m11 = new JMenuItem("学生信息管理");JMenuItem m12 = new JMenuItem("增加学生");JMenuItem m13 = new JMenuItem("退出");m13.addActionListener(new ActionListener()public void actionPerformed(ActionEvent e) exi

16、t_Clicked(););m11.addActionListener(new ActionListener() public void actionPerformed(ActionEvent e) newSubFrm_Clicked(););m12.addActionListener(new ActionListener() public void actionPerformed(ActionEvent e) newAddFrm_Clicked(););m1.add(m11);m1.add(m12);m1.addSeparator();m1.add(m13);bar.add(m1);bar.

17、add(m2);this.setJMenuBar(bar);private void newSubFrm_Clicked() new StudentFrm();private void newAddFrm_Clicked() new AddStudent();private void exit_Clicked() if (JOptionPane.showConfirmDialog(this, "确认退出？", "退出系统",JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE) = JOption

18、Pane.YES_OPTION)System.exit(0);public MainFrm() JPanel jp = (JPanel) this.getContentPane();initMenu();this.setSize(1000, 600);this.setVisible(true);this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);public static void main(String args) new MainFrm();package mydb;import javax.swing.*;import javax.sw

19、ing.table.DefaultTableModel;import java.awt.*;import java.awt.event.*;public class StudentFrm extends JFrame private JTable table = null;private String cols = "学号", "姓名", "专业", "是否有资格" ;private JButton deleteBtn = new JButton("删除");private StudentDao

20、 studentDao = new StudentDao();private void initTable() String rows = studentDao.queryStudents();for (int i = 0; i < rows.length; i+)if ("0".equals(rowsi3)rowsi3 = "有资格"elserowsi3 = "无资格"table = new JTable(rows, cols);private void updateTable() String rows = studentD

21、ao.queryStudents();for (int i = 0; i < rows.length; i+)if ("0".equals(rowsi3)rowsi3 = "有资格"elserowsi3 = "无资格"table.setModel(new DefaultTableModel(rows, cols);private boolean isCellEditable(int row,int col)return true;private void deleteBtn_Clicked() int row = table.g

22、etSelectedRow();if (row > -1) String sno = (String) table.getValueAt(row, 0);studentDao.deleteStudentBySno(sno);JOptionPane.showMessageDialog(this, "学号为" + sno + "记录删除成功!");updateTable();public StudentFrm() JPanel jp = (JPanel) this.getContentPane();initTable();JScrollPane jsp

23、_table = new JScrollPane(table);jp.add(jsp_table);JPanel jp_top = new JPanel();jp_top.add(deleteBtn);jp.add(jp_top, BorderLayout.NORTH);deleteBtn.addActionListener(new ActionListener() public void actionPerformed(ActionEvent e) deleteBtn_Clicked(););this.setSize(600, 400);this.setVisible(true);publi

24、c static void main(String args) new StudentFrm();package mydb;import javax.swing.*;import java.awt.*;import java.awt.event.*;public class AddStudent extends JFrame implements ActionListener StudentDao studentDao = new StudentDao();JButton btn_add=new JButton("确定");JButton btn_del=new JButton("取消");JLabel lb_name=new JLabel("姓名");JLabel lb_snum=new JLabel("学号");JLabel lb_enabled=new JLabel("是否有资格选课");JLabel lb_major=new JLabel("专业");JTextField txt_name=new JTextField();JTextField txt_snum=new JTextField()