一、2019年

1. 第一题

1. Test.java
2. Test.class和Singer.class
3. e:\test01\src\ctgu\edu\cn

   2. 第二题

   import java.util.*;
   public class MessageParser{
    public double getSum(String message){
        String regex = "[^0123456789.]+";
        message = message.replaceAll(regex,"#");
        StringTokenizer fenxi = new StringTokenizer(message,"#");
        double sum = 0;
        while(fenxi.hasMoreTokens()){
            String item = fenxi.nextToken();
            double price += Double.valueOf(item);
            sum = sum + price;
        }
        return sum;
    }
   }

   3. 第三题

   ```java public class Test{ public static void main(String[] args){

    Screen screen = new Screen(false);
    Machine machine = new Machine();
    try{
        machine.checkScreen(screen);
        System.out.println("合格屏");
    }catch(DefectiveScreenException e){
        e.toString();
    }

   } }

class DefectiveScreenException extends Exception{ @Override public void toString(){ System.out.println(“缺陷屏”); } }

class Screen{ public boolean isDefective;

public Screen(){
}
public Screen(boolean isDefective){
    this.isDefective = isDefective;
}

}

class Machine{ public void checkScreen(Screen screen) throws DefectiveScreenException{ if(screen.isDefective()){ throw new DefectiveScreenException(); } } }

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## 4. 第四题
多线程不考，暂时跳过
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## 5. 第五题
```java
public class TestEmployee{
    public static void main(String[] args){
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
        Employee e1 = new Employee(1,"yxr","男",format.parse("2021-12-12"));
        Employee e2 = new Employee(2,"zyl","女",format.parse("2021-12-13"));
        System.out.println(e1);
        System.out.println(e2);
    }
}
class Employee{
    private int no;
    private String name;
    private String sex;
    private Date entryDate;
    public Employee(){
    }
    public Employee(int no,String name,String sex,Date entryDate){
          this.no = no;
        this.name = name;
        this.sex = sex;
        this.entryDate = entryDate;
    }
    public void setNo(int no){
        this.no = no;
    }
    public int getNo(){
        return this.no;
    }
    public void setName(String name){
        this.name = name;
    }
    public String getName(){
        return this.name;
    }
    public void setSex(String sex){
        this.sex = sex;
    }
    public String getSex(){
        return this.sex;
    }
    public void setEntryDate(Date entryDate){
        this.entryDate = entryDate;
    }
    public Date getEntryDate(){
        return this.entryDate;
    }
    @Override
    public String toString(){
        return "姓名：" + name + "入职时间：" + entryDate;
    }
}

6. 第六题

public class FrameTest{
    public static void main(String[] args){
        new MyFrame();
    }
}
class MyFrame extends JFrame{
    public MyFrame(){
        Container container = getContentPane();
        JButton button = new JButton("读取");
        button.addActionListener(new ButtonClickController());
        container.add(button);
        setVisible(true);
        setBounds(300,300,400,400);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }
}
class ButtonClickController implements ActionListener{
    private ArrayList<String> strings;
    private int clickSum;
    public ButtonClickController(){
        strings = new ArrayList<>();
        clickSum = 0;
        FileReader fileReader = null;
        BufferedReader bufferdReader = null;
        try{
            fileReader = new FileReader("test.txt");
            bufferdReader = new BufferedReader(fileReader);
            String str = null;
            while((str = bufferdReader.readLine()) != null){
                strings.add(str);
            }
        }catch(IOException e){
            e.printStackTrace();
        }finally{
            if(bufferdReader != null){
                try{
                    bufferdReader.close();
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
        }
    }
    @Override
    public void actionPerformed(ActionEvent e){
        if(clickSum >= strings.size()){
            throw new RuntimeException("已到达文件末尾！");
        }else{
            System.out.println(strings.get(clickSum));
            clickSum ++;
        }
    }
}

7. 第七题

public class TestShape{
    public static void main(String[] args){
        ArrayList<Shape> list = new ArrayList<>();
        Circle c1 = new Circle(20.0);
        Circle c2 = new Circle(5.2);
        Triangle t1 = new Triangle(10,20);
        Triangle t2 = new Triangle(5,3);
        list.add(c1);
        list.add(c2);
        list.add(t1);
        list.add(t2);
        Collections.sort(list);
        list.forEach(e -> System.out.println(e.getArea()));
    }
}
interface Shape extends Comparable<Shape>{
    double getArea();
    @Override
    int compareTo(Shape o);
}
class Circle implements Shape{
    private double radius;
    public Circle(){
    }
    public Circle(double radius){
        this.radius = radius;
    }
    @Override
    public double getArea(){
        return Math.PI * radius * radius;
    }
    @Override
    public int compareTo(Shape o){
        Double d1 = getArea();
        Double d2 = o.getArea();
        return d1.compareTo(d2);
    }
}
class Triangle implements Shape{
    private double length;
    private double width;
    public Triangle(){
    }
    public Triangle(double length,double width){
        this.length = length;
        this.width = width;
    }
    @Override
    public double getArea(){
        return length*width;
    }
    @Override
    public int compareTo(Shape o){
        Double d1 = getArea();
        Double d2 = o.getArea();
        return d1.compareTo(d2);
    }
}

8. 第八题

TestGUI.java

public class TestGUI{
    public static void main(String[] args){
        javax.swing.SwingUtilities.invokeLater(() -> {
            ComputeFrame win = new ComputeFrame();
            win.setTitle("TestGUI");
            win.setBounds(100,100,420,260);
        });
    }
}

Circle.java

public class Circle{
    private double radius;
    public Circle(double radius){
        this.radius = radius;
    }
    public Circle(){
    }
    public double getArea(){
        return Math.PI * radius * radius;
    }
    public void setRadius(double radius){
        this.radius = radius;
    }
}

ComputeFrame.java

public class ComputeFrame extends JFrame implements ActionListener{
    Circle circle;
    JTextField textRadius;
    JTextArea showArea;
    JButton computeButton;
    ComputeFrame(){
        init();
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    void init(){
        circle = new Circle();
        textRadius = new JTextField(5);
        showArea = new JTextArea();
        computeButton = new JButton("计算面积");
        JPanel pNorth = new JPanel();
        pNorth.add(new JLabel("请输入半径："));
        pNorth.add(textRadius);
        pNorth.add(computeButton);
           computeButton.addActionListener(this);
        add(pNorth,BorderLayout.NORTH);
        add(new JScrollPane(showArea),BorderLayout.CENTER);
    }
    public void actionPerformed(ActionEvent e){
        try{
            double radius = Double.parseDouble(textRadius.getText());
            circle.setRadius(radius);
            double area = circle.getArea();
            showArea.append("半径为：" + radius + "的圆形面积为：" + area + "\n");
        }catch(Exception e){
            showArea.append("\n" + e + "\n");
        }
    }
}