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package llll;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.script.ScriptEngine;

import javax.script.ScriptEngineManager;

import javax.script.ScriptException;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JTextArea;

import javax.swing.JTextField;

public class cal extends JFrame implements ActionListener{

JTextArea txt;

JButton [] a =new JButton[17];

String str[]={"9","8","7","+","6","5","4","-","3","2","1","*","0","/","=","c"};

cal(){

this.setTitle("计算器");

this.setBounds(100, 100, 220, 330);

this.setLayout(null);

txt=new JTextArea();

txt.setBounds(0, 0, 400, 50);

this.add(txt);int y=0;

for(int i=0;i

a[i] =new JButton(str[i]);

if(i%4==0){y=y+60;}

a[i].setBounds(50*(i%4), y, 50, 50);

this.add(a[i]);

a[i].addActionListener(this);

this.setLocationRelativeTo(null);}

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

this.setVisible(true);}

public void actionPerformed(ActionEvent e) {

for(int i=0;i<14;i++){

if(e.getSource()==a[i]){txt.append(str[i]);}}

if(e.getSource()==a[15]){txt.setText("");}

if(e.getSource()==a[14]){

ScriptEngineManager engineManager=new ScriptEngineManager();

ScriptEngine scriptEngine = engineManager.getEngineByName("js");

String s=txt.getText();Object object = null;

try {object = scriptEngine.eval(s);}

catch (ScriptException e1) {

e1.printStackTrace();}

txt.setText(""+object);}}

public static void main(String[]args){

new cal();}}

简单计算器