Java学生成绩查询系统.doc

Chap 2实践2-1class Ex2_1public static void main(String args) float sum=0.0f,count=1.0f;for(int i=1;i=20;+i)count=1.0f;for(int j=1;j=i;+j)count*=j;sum+=count;System.out.println(1+2!+3!+.+20!的值为：+sum);实践2-2public class Ex2_2 public static void main(String args) System.out.println(* 菲波拉挈数列的前20个数为：*); long f1 = 1, f2 = 1; for (int i = 1; i = 10; i +) System.out.print(f1 + + f2 + ); if (i % 2 = 0) System.out.println(); f1 = f1 + f2; f2 = f2 + f1; Chap 3实践3-1public class Student static String name=张三; static int age; public Student() age=18; public static void main(String args) System.out.println(姓名：+name+,年龄：+age); 实践3-2class People String name; People(String name) =name ; /对成员变量name 初始化 class Student extends People String stuID; Student(String name,String stuID) super(name) ; /对继承自父类的成员变量name初始化 this.stuID=stuID ; /对成员变量stuID 初始化 public class PeopleDemo public static void main(String arg) Student stu=new Student(张三,20080601) ; /定义对象 System.out.println(+ +stu.stuID) ; /输出对象的姓名和学号 Chap 4实践4-1public class Ex4_1 String str; public Ex4_1(String str) this.str = str; int getlength() return(str.length(); public static void main(String args) Ex4_1 test = new Ex4_1(Hello); System.out.println(字符串是:+test.str+ 长度为：+test.getlength(); 实践4-2import java.util.*;import java.io.*;public class Ex4_2 public static void main(String args) String str1 = new String(); String str2 = new String(); char ch; Scanner reader= new Scanner(System.in); System.out.println(输入字符串：); str1=reader.next(); /输入字符串 System.out.println(输入要删除的字符：); str2=reader.next(); /输入穿要删除的字符 ，以字符串的形式输入 ch=str2.charAt(0); /将字符串转换为字符 str2=str1.replace(ch, ); /用空格替代指定字符 System.out.println(删除字符后的字符串 +str2); Chap 5实践5-1public class Ex5_1 public static void main(String args) try int num = new int 10; System.out.println(num10 is + num10); catch (Exception ex) System.out.println(Exception); catch (RuntimeException ex) System.out.println(RuntimeException); catch (ArithmeticException ex) System.out.println(ArithmeticException); 实践5-2public class Ex5_2 static double cal(double a, double b) throws IllegalArgumentException double value; if ( b = 0 ) / 抛出IllegalArgumentException异常 throw new IllegalArgumentException(除数不能为0); else value = a/b; if ( value 0 ) / 抛出IllegalArgumentException异常 throw new IllegalArgumentException(运算结果小于0); return value; public static void main(String args) double result; try double a = Double.parseDouble(args0); double b = Double.parseDouble(args1); result = cal(a, b); System.out.println(运算结果是: + result); catch( IllegalArgumentException e ) / 处理llegalArgumentException异常 System.out.println(异常说明: +e.getMessage(); Chap 6实践6-1import javax.swing.JFrame; import javax.swing.JLabel; import java.awt.Font; public class ex6_1 public static void main(String args) JFrame frame=new JFrame(); JLabel label1=new JLabel(JAVA Programming); Font font1=label1.getFont(); font1=new Font(Courier, font1.getStyle(), 20); label1.setFont(font1); frame.getContentPane().add(label1); frame.pack(); frame.setVisible(true); 实践6-2import javax.swing.*;public class ex6_2 extends JFrame public ex6_2() super(第一个窗体); setDefaultCloseOperation(DISPOSE_ON_CLOSE); setSize(300, 150); setLocationRelativeTo(null); setVisible(true); public static void main(String args) new ex6_2(); Chap 7实践7-1import javax.swing.*;import java.awt.*;public class ex7_1 extends JFrame ex7_1()super(程序调试);setLayout(new FlowLayout();JButton jbtn1=new JButton(确定);JButton jbtn2=new JButton(取消);this.getContentPane().add(jbtn1); this.getContentPane().add(jbtn2); this.setVisible(true);this.setSize(300,150); public static void main( String args) new ex7_1 (); 实践7-2import javax.swing.*;import java.awt.*;public class Ex7_2 extends JFrame Panel pan0,pan1,pan2,pan3,pan4,pan5,pan6,pan7;Panel pan; String numStr=1,2 ABC,3 DEF,4 GHI,5 JKL,6 MNO,7 PQRS,8 TUV,9 WXYZ,*,0,#;Ex7_2()super(手机键盘界面);pan=new Panel8;for(int j=0;j8;j+)panj=new Panel(); ImageIcon icon=new ImageIcon(JM1.jpg); JLabel jlab1=new JLabel(icon,SwingConstants.CENTER); pan5.add(jlab1); pan0.setLayout(new GridLayout(4,3); for(int i=0;inumStr.length;i+) pan0.add(new JButton(numStri); pan1.setLayout(new GridLayout(2,1); pan1.add(new JButton(确定); pan1.add(new JButton(Call); pan2.setLayout(new GridLayout(2,1); pan2.add(new JButton(取消); pan2.add(new JButton(ON/OFF); pan7.setLayout(new BorderLayout(); pan7.add(North,new JButton(上); pan7.add(South,new JButton(下); pan7.add(East,new JButton(右); pan7.add(West,new JButton(左); pan3.setLayout(new BorderLayout(); pan3.add(pan7); pan4.setLayout(new GridLayout(1,3); pan4.add(pan1); pan4.add(pan3); pan4.add(pan2); pan6.setLayout(new GridLayout(3,1); pan6.add(pan5); pan6.add(pan4); pan6.add(pan0); getContentPane().add(pan6); setVisible(true);setResizable(false);setLocation(400,150);pack();public static void main(String args)new Ex7_2();Chap 8实践8-1import java.awt.event.*;import javax.swing.*;import java.awt.*;public class Ex8_1 extends JFrame implements WindowListener public Ex8_1() Container con=this.getContentPane(); con.setLayout(new FlowLayout(); setBounds(0,0,200,200); setVisible(true); addWindowListener(this); public static void main(String args)new Ex8_1(); public void windowClosing(WindowEvent e)System.out.println(The window closing); System.exit(0); public void windowClosed(WindowEvent e) public void windowOpened(WindowEvent e)System.out.println(window opened); public void windowIconified(WindowEvent e) public void windowDeiconified(WindowEvent e) public void windowDeactivated(WindowEvent e) System.out.println(The window deactived); public void windowActivated(WindowEvent e)System.out.println(The window Activated); 实践8-2 import java.awt.*; import java.awt.event.*; import javax.swing.*; public class Ex8_2 extends JFrame implements ActionListener static Ex8_2 frm=new Ex8_2(); static JButton btn1=new JButton(Yellow); static JButton btn2=new JButton(Green); public static void main(String args) btn1.addActionListener(frm); / 把事件监听者frm向btn1注册 btn2.addActionListener(frm); / 把事件聆听者frm向btn2注册 frm.setTitle(Action Event); frm.setLayout(new FlowLayout(FlowLayout.CENTER); frm.setSize(200,150); frm.getContentPane().add(btn1); frm.getContentPane().add(btn2); frm.setVisible(true); public void actionPerformed(ActionEvent e) JButton btn=(JButton) e.getSource(); / 取得事件源对象 if(btn=btn1) / 如果是按下btn1按钮 frm.getContentPane().setBackground(Color.yellow); else if(btn=btn2) / 如果是按下btn2按钮 frm.getContentPane().setBackground(Color.green); Chap 9实践9-1import javax.swing.*;import java.awt.*;import javax.swing.event.*;public class Ex9_1 extends JFrame implements ListSelectionListener String pro = 软件专业, 网络专业, 动漫专业; JPanel p1; JComboBox courseCombo; JList proList; Ex9_1() proList = new JList(pro); proList.addListSelectionListener(this); courseCombo = new JComboBox(); p1 = new JPanel(); add(p1); p1.add(proList); p1.add(courseCombo); add(p1); setSize(400,200); setVisible(true); public void valueChanged(ListSelectionEvent e) Object obj = e.getSource(); if(obj=proList)courseCombo.removeAllItems();int nIndex = proList.getSelectedIndex();switch(nIndex )case 0: courseCombo.addItem (Java程序设计) ; courseCombo.addItem (J2ee项目开发) ; break;case 1:courseCombo.addItem (网络基本原理) ; courseCombo.addItem (局域网技术与组网工程) ; courseCombo.addItem (网络操作系统) ; break; case 2: courseCombo.addItem (动漫造型) ; courseCombo.addItem (漫画制作) ; break; public static void main(String args) new Ex9_1(); 实践9-2import javax.swing.*;import java.awt.*;import java.awt.event.*;public class Ex9_2 extends JFrame implements ItemListener JRadioButton rad1=new JRadioButton(说法正确,false); JRadioButton rad2=new JRadioButton (说法错误,false); ButtonGroup btg=new ButtonGroup (); JTextArea ta=new JTextArea(2,10); JTextField tf=new JTextField(4); JLabel lb=new JLabel(你的选择:); JPanel jp=new JPanel(); String text=BoxLayout是由Swing 提供的布局管理器，功能上同 GridBagLayout 一样强大，而且更加易用。; public Ex9_2() Container c=this.getContentPane(); setLayout(new FlowLayout(); btg.add(rad1); btg.add(rad2); ta.setText(text); c.add(ta); rad1.addItemListener(this); rad2.addItemListener(this); c.add(rad1); c.add(rad2);c.add(lb); c.add(tf); this.setSize(520,150); this.setVisible(true); public void itemStateChanged(ItemEvent e) if(e.getSource()=rad1) rad2.setSelected(false); tf.setText(正确!); else rad1.setSelected(false); tf.setText(错误!); public static void main(String args) new Ex9_2(); Chap 10实践10-1import java.io.*;import java.util.*;public class ex10_1 public static void main(String args) String s=; try RandomAccessFile f1=new RandomAccessFile(a.txt,rw); RandomAccessFile f2=new RandomAccessFile(b.txt,rw); s=f1.readLine()+f2.readLine();