Java例题

最新推荐文章于 2021-02-24 11:43:55 发布

AWA124

最新推荐文章于 2021-02-24 11:43:55 发布

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本文链接：https://blog.youkuaiyun.com/AWA124/article/details/80946988

本文深入探讨了Java编程中的典型问题及解决方案，涵盖了基础语法、面向对象特性、异常处理和常用数据结构的应用。通过实例分析，旨在提升读者的Java实战能力。

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简单计算器

public class Example9_8 {

	public static void main(String[] args) {
		WindowOperation win =new WindowOperation();
		win.setBounds(100,100,390,360);
		win.setTitle("简单计算");
	}
}
import java.awt.*;
import javax.swing.*;
import java.io.*;
public class WindowOperation extends JFrame{
     JTextField inputNumberOne,inputNumberTwo;
     JComboBox choiceFuhao;
     JTextArea textShow;
     JButton button;
     OperatorListener operator;
     ComputerListener computer;
     public WindowOperation() {
    	 init();
    	 setVisible(true);
    	 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     }
     void init() {
    	 setLayout(new FlowLayout());
    	 inputNumberOne = new JTextField(5);
    	 inputNumberTwo = new JTextField(5);
    	 choiceFuhao = new JComboBox();
    	 button = new JButton("计算");
    	 choiceFuhao.addItem("选择运算符号");
    	 String [] a = {"+","-","*","/"};
    	 for(int i=0;i<a.length;i++) {
    		 choiceFuhao.addItem(a[i]);
    	 }
    	 textShow = new JTextArea(9,30);
    	 operator = new OperatorListener();
    	 computer = new ComputerListener();
    	 operator.setJComboBox(choiceFuhao);
    	 operator.setWorkTogether(computer);
    	 computer.setJTextFieldOne(inputNumberOne);
    	 computer.setJTextFieldOne(inputNumberTwo);
    	 computer.setJTextArea(textShow);
    	 choiceFuhao.addItemListener(operator);
    	 button.addActionListener(computer);
    	 add(inputNumberOne);
    	 add(choiceFuhao);
    	 add(inputNumberTwo);
    	 add(button);
    	 add(new JScrollPane(textShow));
     }
}
import java.awt.event.*;
import javax.swing.*;
public class OperatorListener implements ItemListener {
     JComboBox choice;
     ComputerListener workTogether;
     public void setJComboBox(JComboBox box) {
    	 choice = box;
     }
     public void setWorkTogether(ComputerListener computer) {
    	 workTogether = computer;
     }
     public void itemStateChanged(ItemEvent e) {
    	 String fuhao = choice.getSelectedItem().toString();
    	 workTogether.setFuhao(fuhao);
     }
}
import java.awt.event.*;
import javax.swing.*;
public class ComputerListener implements ActionListener{
     JTextField inputNumberOne,inputNumberTwo;
     JTextArea textShow;
     String fuhao;
     public void setJTextFieldOne(JTextField t) {
    	 inputNumberOne = t;
     }
     public void setJTextFieldTwo(JTextField t) {
    	 inputNumberTwo = t;
     }
     public void setJTextArea(JTextArea area) {
    	 textShow = area;
     }
     public void setFuhao(String s) {
    	 fuhao = s;
     }
     public void actionPerformed(ActionEvent e) {
    	 try {
    		 double number1 = Double.parseDouble(inputNumberOne.getText());
    		 double number2 = Double.parseDouble(inputNumberTwo.getText());
    		 double result = 0;
    		 if(fuhao.equals("+")) {
    			 result = number1+number2;
    		 }
    		 else if(fuhao.equals("-")) {
    			 result = number1-number2;
    		 }
    		 else if(fuhao.equals("*")) {
    			 result = number1*number2;
    		 }
    		 else if(fuhao.equals("/")) {
    			 result = number1/number2;
    		 }
    		 textShow.append(number1+" "+fuhao+" "+number2+" = "+result+"\n");
    	 }
    	 catch(Exception exp) {
    		 textShow.append("\n请输入数字字符\n");
    	 }
     }
}