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给你一个参考，希望不62616964757a686964616fe58685e5aeb931333330343261要被百度吞了当晚餐

import java.awt.BorderLayout;

import java.awt.GridLayout;

import java.awt.event.MouseEvent;

import java.awt.event.MouseListener;

import java.text.DecimalFormat;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JTextField;

public class Calculator {

//计算器面板

private JFrame f = new JFrame("Calculator");

//输入面扳

private JPanel inputPanel = new JPanel();

//加减乘除面板

private JPanel operationPanel = new JPanel();

//数字面板

private JPanel buttonsPanel = new JPanel();

//输入数据文本框

private JTextField input = new JTextField(20);

//退格键

private JButton backspace = new JButton("BackSpace");

//清空

private JButton CE = new JButton("CE ");

//删除

private JButton C = new JButton("C ");

//四则运算符号键

private JButton add = new JButton("+");

private JButton sub = new JButton("-");

private JButton mul = new JButton("*");

private JButton div = new JButton("/");

//小数点

private JButton decimal = new JButton(".");

//等号

private JButton equal = new JButton("=");

//数字键

private JButton zero = new JButton("0");

private JButton one = new JButton("1");

private JButton two = new JButton("2");

private JButton three = new JButton("3");

private JButton four = new JButton("4");

private JButton five = new JButton("5");

private JButton six = new JButton("6");

private JButton seven = new JButton("7");

private JButton eight = new JButton("8");

private JButton nine = new JButton("9");

private String num1 = "";//保存第一个运算数字

private String operator = "";//保存运算符号

public static void main(String[] args) {

new Calculator();//new计算器实例

}

public Calculator(){

//添加组件，布局

inputPanel.add(input);

f.add(inputPanel, BorderLayout.NORTH);

operationPanel.add(backspace);

operationPanel.add(CE);

operationPanel.add(C);

f.add(operationPanel, BorderLayout.CENTER);

buttonsPanel.add(add);

buttonsPanel.add(sub);

buttonsPanel.add(mul);

buttonsPanel.add(div);

buttonsPanel.add(one);

buttonsPanel.add(two);

buttonsPanel.add(three);

buttonsPanel.add(zero);

buttonsPanel.add(four);

buttonsPanel.add(five);

buttonsPanel.add(six);

buttonsPanel.add(decimal);

buttonsPanel.add(seven);

buttonsPanel.add(eight);

buttonsPanel.add(nine);

buttonsPanel.add(equal);

buttonsPanel.setLayout(new GridLayout(4, 4));

f.add(buttonsPanel, BorderLayout.SOUTH);

//注册各个组件监听事件

backspace.addMouseListener(new OperationMouseListener());

CE.addMouseListener(new OperationMouseListener());

C.addMouseListener(new OperationMouseListener());

decimal.addMouseListener(new OperationMouseListener());

equal.addMouseListener(new OperationMouseListener());

//注册四则运算监听

add.addMouseListener(new CalcMouseListener());

sub.addMouseListener(new CalcMouseListener());

mul.addMouseListener(new CalcMouseListener());

div.addMouseListener(new CalcMouseListener());

//注册数字监听事件

zero.addMouseListener(new NumberMouseListener());

one.addMouseListener(new NumberMouseListener());

two.addMouseListener(new NumberMouseListener());

three.addMouseListener(new NumberMouseListener());

four.addMouseListener(new NumberMouseListener());

five.addMouseListener(new NumberMouseListener());

six.addMouseListener(new NumberMouseListener());

seven.addMouseListener(new NumberMouseListener());

eight.addMouseListener(new NumberMouseListener());

nine.addMouseListener(new NumberMouseListener());

f.setVisible(true);

f.pack();

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

private class NumberMouseListener implements MouseListener{

public void mouseClicked(MouseEvent e) {

if(input.getText().trim().equals("0")){//如果文本框已经是0，结果还是0

input.setText(((JButton)e.getSource()).getText().trim());

}else{//否则的话，把0添加到后面，譬如文本框是1，结果就为10

input.setText(input.getText().concat(((JButton)e.getSource()).getText().trim()));

}

}

public void mouseEntered(MouseEvent e) {}

public void mouseExited(MouseEvent e) {}

public void mousePressed(MouseEvent e) {}

public void mouseReleased(MouseEvent e) {}

}

private class CalcMouseListener implements MouseListener{

//如果输入的是运算符号，保存第一个结果和运算符号

public void mouseClicked(MouseEvent e) {

num1 = input.getText().trim();input.setText("");

operator = ((JButton)e.getSource()).getText().trim();

}

public void mouseEntered(MouseEvent e) {}

public void mouseExited(MouseEvent e) {}

public void mousePressed(MouseEvent e) {}

public void mouseReleased(MouseEvent e) {}

}

private class OperationMouseListener implements MouseListener{

public void mouseClicked(MouseEvent e) {

if(e.getSource() == backspace){//退格键，删除一个直到没有字符删除

String inputText = input.getText();

if(inputText.length() > 0){

input.setText(inputText.substring(0, inputText.length() - 1));

}

}else if(e.getSource() == C){

input.setText("0");//C，清空所有运算数字和符号

num1 = "";

}else if(e.getSource() == CE){

input.setText("0");//CE-->将文本框置为0

}else if(e.getSource() == decimal){

String text = input.getText().trim();

//如果按了小数点，如果文本框已经有小数点，不做任何操作，否则在结果后面加上小数点

if(text.indexOf(".") == -1){

input.setText(text.concat("."));

}

}else if(e.getSource() == equal){

//如果是等号

if(!operator.trim().equals("")){

if(!input.getText().trim().equals("")){

double result = 0D;

if(operator.equals("+")){//执行加法运算

result = Double.parseDouble(num1) + Double.parseDouble(input.getText().trim());

}else if(operator.equals("-")){//减法运算

result = Double.parseDouble(num1) - Double.parseDouble(input.getText().trim());

}else if(operator.equals("*")){//乘法运算

result = Double.parseDouble(num1) * Double.parseDouble(input.getText().trim());

}else if(operator.equals("/")){//除法运算

result = Double.parseDouble(num1) / Double.parseDouble(input.getText().trim());

}

//格式化最终结果，保留两位小数点

input.setText(new DecimalFormat("0.00").format(result));

}

}

}

}

public void mouseEntered(MouseEvent e) {}

public void mouseExited(MouseEvent e) {}

public void mousePressed(MouseEvent e) {}

public void mouseReleased(MouseEvent e) {}

}

}

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