使用Java实现的简单的计算器

小学期自己写的一个程序，时间有限，好多东西都是不太完全，但是没有bug，计算的是使用javax.Script的方法，欢迎拍砖

package calculate;
/**
* @author Wayne;
* @time 2014年7月14日;
* @project java计算器2.0;
*/

import java.awt.*;
import java.awt.event.*;
import java.text.DecimalFormat;

import javax.swing.*;
import javax.swing.JOptionPane;
import javax.script.*;

public class Calcul extends JFrame implements ActionListener,KeyListener
{
private static final long serialVersionUID = 6256855493544342895L;

//一些全局初始化
JPanel buttonPanel = new JPanel(new GridLayout(5,4,3,3));//定义5*4网格，横向竖向间距为3px
JTextField dataspace = new JTextField("");//显示输入的文本
JTextField message = new JTextField("就绪");//标题用户显示提示信息
String str[] = {"清除(C)","←","（","）","7","8","9","÷","4","5","6","×","1","2","3","-",".","0","等于(R)","+"};//按钮文字
private JButton btn[] = new JButton[str.length];//新建按钮

//字体和颜色
Font font = new Font("微软雅黑",Font.BOLD,22);//字体初始化
Color wordcolor = new Color(255,255,255);//字体设置为白色
Color textboxcolor = new Color(124,97,76);//消息框颜色为灰色
Color textboxcolor1 = new Color(125,125,125);//文本框颜色为灰色

public Calcul()
{
//一些初始化
setTitle("计算器");
setSize(WIDTH,HEIGHT);
setResizable(false);
setIconImage(Toolkit.getDefaultToolkit().getImage("icon.png"));

//增加按钮并设置监听颜色等
for(int i = 0;i<str.length;i++)
{
btn[i] = new JButton(str[i]);
btn[i].setFont(font);
btn[i].addActionListener(this);
btn[i].addKeyListener(this);
// if((i>3 && i<7 ) || (i>7 && i<11) || ( i>11 && i<15) || i == 17)
btn[i].setBackground(new Color(104,152,104));
//else
// btn[i].setBackground(new Color(99,154,157));
btn[i].setForeground(wordcolor);
buttonPanel.add(btn[i]);
}
btn[0].setBackground(new Color(204,88,56));
btn[7].setBackground(new Color(67,160,193));
btn[11].setBackground(new Color(67,160,193));
btn[15].setBackground(new Color(67,160,193));
btn[19].setBackground(new Color(67,160,193));
message.addKeyListener(this);

//增加文本面板

JPanel textPanel = new JPanel(new GridLayout(2,1));

//将文本框加入到文本面板中

//提示框
message.setFont(font);
message.setPreferredSize(new Dimension(30,50));
message.setBackground(textboxcolor);
message.setForeground(wordcolor);
message.setEditable(false);
textPanel.add(message);

//缓冲区
dataspace.setFont(font);
dataspace.setPreferredSize(new Dimension(30,60));
dataspace.setBackground(textboxcolor1);
dataspace.setForeground(wordcolor);
dataspace.setEditable(false);
textPanel.add(dataspace);

//将组件加入到容器中
Container contentPane = getContentPane();
contentPane.add(buttonPanel,BorderLayout.CENTER);
contentPane.add(textPanel,BorderLayout.NORTH);

}
public static final int WIDTH = 500;
public static final int HEIGHT = 500;

public static void main(String[] args)
{
Calcul frame = new Calcul();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
frame.setLocation((dim.width - 350)/2,(dim.height - 500)/2);
frame.setVisible(true);
}

//判断输入是否为+-*/.的函数
public boolean NotSymbol(String str)
{
char strc = str.charAt(0);
if(strc == '*' || strc == '/' || strc == '+' || strc == '-' || strc == '.')
{
return false;
}
else
{
return true;
}
}
//判断前一个是否为+-*/.的函数
public boolean PreNotSym(String str)
{
String pre = str.substring(str.length()-1, str.length());
if(NotSymbol(pre))
return true;
else
return false;
}
//追加函数
public String addnum(String add)
{
String addbefore=dataspace.getText().trim();
String addafter = null;
message.setText("输入的为：");

if(addbefore.length() == 0 )
{
if(NotSymbol(add))
addafter=addbefore+add;
else if( !NotSymbol(add))
addafter = addbefore;
}

else if(addbefore.length() >= 2 )
{
if(PreNotSym(addbefore))
{

addafter=addbefore+add;
}
else
{
if(NotSymbol(add))
addafter = addbefore + add;
else if( !NotSymbol(add))
addafter = addbefore;
}

}
else if(addbefore.length() == 1)
{
addafter = addbefore + add;
}
return addafter;
}
@Override
public void actionPerformed(ActionEvent e)
{
//清空
if (e.getSource() == btn[0] )
{
message.setText("就绪");
dataspace.setText("");
}

//退格
else if (e.getSource() == btn[1])
{
message.setText("就绪");
String data = dataspace.getText().trim();
if(data.length()>0)
{
if(data.charAt(0) != '-')
{
if(data.length() >1)
{
if(data.charAt(data.length() - 2) == '.')
{
data = data.substring(0,data.length() -1);
dataspace.setText(data);
}
data = data.substring(0,data.length() - 1);
dataspace.setText(data);
}
else if(data.length() == 1)
{
dataspace.setText("");
}
}
else if(data.charAt(0) == '-')
{
if(data.length() >2)
{
if(data.charAt(data.length() - 2) == '.')
{
data = data.substring(0,data.length() -1);
dataspace.setText(data);
}
data = data.substring(0,data.length() - 1);
dataspace.setText(data);
}
else if(data.length() == 2)
{
dataspace.setText("0");
}
}
else if(data == "0")
{
dataspace.setText("");
}
}
else
{}
}

//左括号
else if(e.getSource() == btn[2])
{
String key = "(";
dataspace.setText(addnum(key));
}

//右括号
else if(e.getSource() == btn[3])
{
String key = ")";
dataspace.setText(addnum(key));
}

//等号
else if(e.getSource() == btn[18])
{
message.setText("计算得到的结果为：");
ScriptEngineManager sem = new ScriptEngineManager();
ScriptEngine se = sem.getEngineByName("js");
try
{
int leng = dataspace.getText().length();
if(leng==0)
{
message.setText("你好像没输入数据哦~！");
}
else
{
DecimalFormat df = new DecimalFormat("#.##"); //设置数据格式
Object result = se.eval(dataspace.getText());
double value = Double.parseDouble(df.format(result));
String valuestr = String.valueOf(value);
dataspace.setText(valuestr);
}
}
catch (ScriptException evt)
{
message.setText("表达式似乎有错呢!请重新编辑");
}
catch(NumberFormatException evt)
{
message.setText("除数不能为0哦,请重新编辑");
}
}

//加点
else if(e.getSource() == btn[16])
{
String key = ".";
dataspace.setText(addnum(key));
}

//加号
else if(e.getSource() == btn[19])
{
String key = "+";
dataspace.setText(addnum(key));
}

//减号
else if(e.getSource() == btn[15])
{
String key = "-";
dataspace.setText(addnum(key));
}

//乘号
else if(e.getSource() == btn[11])
{
String key = "*";
dataspace.setText(addnum(key));
}

//除号
else if(e.getSource() == btn[7])
{
String key = "/";
dataspace.setText(addnum(key));
}

//数字7
else if(e.getSource() == btn[4])
{
String key = "7";
dataspace.setText(addnum(key));
}

//数字8
else if(e.getSource() == btn[5])
{
String key = "8";
dataspace.setText(addnum(key));
}

//数字9
else if(e.getSource() == btn[6])
{
String key = "9";
dataspace.setText(addnum(key));
}

//数字4
else if(e.getSource() == btn[8])
{
String key = "4";
dataspace.setText(addnum(key));
}

//数字5
else if(e.getSour
4000
ce() == btn[9])
{
String key = "5";
dataspace.setText(addnum(key));
}

//数字6
else if(e.getSource() == btn[10])
{
String key = "6";
dataspace.setText(addnum(key));
}

//数字1
else if(e.getSource() == btn[12])
{
String key = "1";
dataspace.setText(addnum(key));
}

//数字2
else if(e.getSource() == btn[13])
{
String key = "2";
dataspace.setText(addnum(key));
}

//数字3
else if(e.getSource() == btn[14])
{
String key = "3";
dataspace.setText(addnum(key));
}

//数字0
else if(e.getSource() == btn[17])
{
String key = "0";
dataspace.setText(addnum(key));

}
}

@Override
public void keyTyped(KeyEvent e) {
// TODO 自动生成的方法存根

}

@Override
//按下按钮
public void keyReleased(KeyEvent e)
{
int keycode = e.getKeyCode();
//退出
if(keycode == 81)
{
int i = JOptionPane.showConfirmDialog(null, "是否退出？","提示:", JOptionPane.YES_NO_OPTION);
if(i == JOptionPane.OK_OPTION)
{
System.exit(0);
}
else{ }
}
//清空
if (keycode == 67 )
{
message.setText("就绪");
dataspace.setText("");
}

//点
else if(keycode == 110)
{
String key = ".";
dataspace.setText(addnum(key));
}

//加号
else if(keycode == 107)
{
String key = "+";
dataspace.setText(addnum(key));
}

//减号
else if(keycode == 109)
{
String key = "-";
dataspace.setText(addnum(key));
}

//乘号
else if(keycode == 106)
{
String key = "*";
dataspace.setText(addnum(key));
}

//除号
else if(keycode == 111)
{
String key = "/";
dataspace.setText(addnum(key));
}

//数字7
else if(keycode == 103 || keycode == 55)
{
String key = "7";
dataspace.setText(addnum(key));
}

//数字8
else if(keycode == 104 || keycode == 56)
{
String key = "8";
dataspace.setText(addnum(key));
}

//数字9
else if(keycode == 105 || (keycode == 57 && !e.isShiftDown()))
{
String key = "9";
dataspace.setText(addnum(key));
}

//数字4
else if(keycode == 100 || keycode == 52)
{
String key = "4";
dataspace.setText(addnum(key));
}

//数字5
else if(keycode == 101 || keycode == 53)
{
String key = "5";
dataspace.setText(addnum(key));
}

//数字6
else if(keycode == 102 || keycode == 54)
{
String key = "6";
dataspace.setText(addnum(key));
}

//数字1
else if(keycode == 97 || keycode == 49)
{
String key = "1";
dataspace.setText(addnum(key));
}

//数字2
else if(keycode == 98 || keycode == 50)
{
String key = "2";
dataspace.setText(addnum(key));
}

//数字3
else if(keycode == 99 || keycode == 51)
{
String key = "3";
dataspace.setText(addnum(key));
}

//数字0
else if(keycode == 96 || (keycode == 48 && !e.isShiftDown()))
{
String key = "0";
dataspace.setText(addnum(key));
}

//按下R
else if(keycode == 82)
{
message.setText("计算得到的结果为：");
ScriptEngineManager sem = new ScriptEngineManager();
ScriptEngine se = sem.getEngineByName("js");
try
{
int leng = dataspace.getText().length();
if(leng==0)
{
message.setText("你好像没输入数据哦!");
}
else
{
DecimalFormat df = new DecimalFormat("#.##"); //设置数据格式
Object result = se.eval(dataspace.getText());
double value = Double.parseDouble(df.format(result));
String valuestr = String.valueOf(value);
dataspace.setText(valuestr);
}
}
catch (ScriptException evt)
{
message.setText("表达式似乎有错呢!请重新编辑");
}
catch(NumberFormatException evt)
{
message.setText("除数不能为0哦,请重新编辑");
}
}

//按下Backspace
else if (keycode == 8)
{
message.setText("就绪");
String data = dataspace.getText().trim();
if(data.length()>0)
{
if(data.charAt(0) != '-')
{
if(data.length() >1)
{
if(data.charAt(data.length() - 2) == '.')
{
data = data.substring(0,data.length() -1);
dataspace.setText(data);
}
data = data.substring(0,data.length() - 1);
dataspace.setText(data);
}
else if(data.length() == 1)
{
dataspace.setText("");
}
}
else if(data.charAt(0) == '-')
{
if(data.length() >2)
{
if(data.charAt(data.length() - 2) == '.')
{
data = data.substring(0,data.length() -1);
dataspace.setText(data);
}
data = data.substring(0,data.length() - 1);
dataspace.setText(data);
}
else if(data.length() == 2)
{
dataspace.setText("0");
}
}
else if(data == "0")
{
dataspace.setText("");
}
}
else
{}
}

//左括号
else if(keycode == 57 && e.isShiftDown())
{
String key = "(";
dataspace.setText(addnum(key));
}

//右括号
else if(keycode == 48 && e.isShiftDown())
{
String key = ")";
dataspace.setText(addnum(key));
}

}

@Override
public void keyPressed(KeyEvent e) {
// TODO 自动生成的方法存根

}
}