简易计算器小程序代码：

package jisuanqi;

//声明须要插入的包

import java.awt.*;

import java.lang.Object;

import java.lang.String;

import javax.swing.*;

import java.awt.event.*;

import java.awt.TextComponent;

//声明一个主类jisuanqi。继续窗体类Frame

public class jisuanqi extends Frame{

//声明16个Button

Button anjian1, anjian2, anjian3, anjian4, anjian5, anjian6, anjian7, anjian8, anjian9, anjian10, anjian11, anjian12, anjian13, anjian14,anjian15,anjian16;

//声明文本框。用于接收数字和计算

TextField numText;

//声明面板容器，用于存放各种button

Panel anjianPanel;

//构造方法初始化button

jisuanqi(String title){

super(title);

anjian1=new Button("0");

anjian2=new Button("1");

anjian3=new Button("2");

anjian4=new Button("3");

anjian5=new Button("4");

anjian6=new Button("5");

anjian7=new Button("6");

anjian8=new Button("7");

anjian9=new Button("8");

anjian10=new Button("9");

anjian11=new Button("+");

anjian12=new Button("-");

anjian13=new Button("*");

anjian14=new Button("/");

anjian15=new Button("=");

anjian16=new Button("清空");

//初始化文本框。将文本的值设置为“0”

numText=new TextField("0");

//实例化面板;

anjianPanel=new Panel();

//设置button

anjianPanel.setLayout(new FlowLayout());

//实例化button

anjian1.addActionListener(new anjianAction());

anjian2.addActionListener(new anjianAction());

anjian3.addActionListener(new anjianAction());

anjian4.addActionListener(new anjianAction());

anjian5.addActionListener(new anjianAction());

anjian6.addActionListener(new anjianAction());

anjian7.addActionListener(new anjianAction());

anjian8.addActionListener(new anjianAction());

anjian9.addActionListener(new anjianAction());

anjian10.addActionListener(new anjianAction());

anjian11.addActionListener(new anjianAction());

anjian12.addActionListener(new anjianAction());

anjian13.addActionListener(new anjianAction());

anjian14.addActionListener(new anjianAction());

anjian15.addActionListener(new anjianAction());

anjian16.addActionListener(new anjianAction());

//将各个button加入到面板容器中

anjianPanel.add(anjian1);

anjianPanel.add(anjian2);

anjianPanel.add(anjian3);

anjianPanel.add(anjian4);

anjianPanel.add(anjian5);

anjianPanel.add(anjian6);

anjianPanel.add(anjian7);

anjianPanel.add(anjian8);

anjianPanel.add(anjian9);

anjianPanel.add(anjian10);

anjianPanel.add(anjian11);

anjianPanel.add(anjian12);

anjianPanel.add(anjian13);

anjianPanel.add(anjian14);

anjianPanel.add(anjian15);

anjianPanel.add(anjian16);

//为文本框加入事件

numText.addTextListener(new TextListener() {

public void textValueChanged(TextEvent e) {

if(numText.getText().indexOf("0",0)!=-1){

numText.getText().replace("0","");

}

}

});

addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {

System.exit(0);

}

});

//将文本框放置在顶部

add(numText,BorderLayout.NORTH);

//加入button

add(anjianPanel,BorderLayout.CENTER);

//设置文本框属性

numText.setEditable(false);

}

//没有不论什么操作的值

int num=0;

//numStr是文本框的值

String numStr=null;

Boolean chinage=false;

//设置button

public int check(){

numStr = numText.getText();

if (numStr.indexOf("+") == 0) {

numStr = numStr.replace('+', '0');

num = num + Integer.parseInt(numStr);

return num;

}

else if (numStr.indexOf("-") != -1) {

numStr = numStr.replace("-", "0");

num = num - Integer.parseInt(numStr);

return num;

}

else if(numStr.indexOf("*")!=-1){

numStr=numStr.replace('*','0');

num = num * Integer.parseInt(numStr);

return num;

}

else if(numStr.indexOf("/")!=-1){

numStr=numStr.replace('/','0');

try{

num = num / Integer.parseInt(numStr);

return num;

}

catch(ArithmeticException e){

JOptionPane.showMessageDialog(null,"除数不能为空!","消息!",1);

return num;

}

}

else return num=Integer.parseInt(numStr);

}

//创建事件

private class anjianAction implements ActionListener{

public void actionPerformed(ActionEvent event){

if(event.getActionCommand()=="0"){

if(!numText.getText().equals("0"))

numText.setText(numText.getText()+0);

}

if(event.getActionCommand()=="1")

numText.setText(numText.getText()+1);

if(event.getActionCommand()=="2")

numText.setText(numText.getText()+2);

if(event.getActionCommand()=="3")

numText.setText(numText.getText()+3);

if(event.getActionCommand()=="4")

numText.setText(numText.getText()+4);

if(event.getActionCommand()=="5")

numText.setText(numText.getText()+5);

if(event.getActionCommand()=="6")

numText.setText(numText.getText()+6);

if(event.getActionCommand()=="7")

numText.setText(numText.getText()+7);

if(event.getActionCommand()=="8")

numText.setText(numText.getText()+8);

if(event.getActionCommand()=="9")

numText.setText(numText.getText()+9);

if(event.getActionCommand()=="清空"){

numText.setText("0");

num=0;

}

if(event.getActionCommand()=="+"){

//调用check();方法

check();

numText.setText("+");

}

if(event.getActionCommand()=="-"){

check();

numText.setText("-");

}

if(event.getActionCommand()=="*"){

check();

numText.setText("*");

}

if(event.getActionCommand()=="/"){

if(numStr=="/0"){

JOptionPane.showMessageDialog(null,"除数不能为空!","消息!",1);

}

check();

numText.setText("/");

}

if(event.getActionCommand()=="="){

check();

numText.setText(""+num);

}

}

}

public static void main(String[] args){

jisuanqi jisuanqi=new jisuanqi("计算器");

jisuanqi.setBackground(Color.CYAN);

jisuanqi.setSize(300,280);

//设置窗体大小

jisuanqi.setLocation(550,350);

//设置界面属性

jisuanqi.setVisible(true);

}

}