工程名随意，文件名必须为Jisuanqi.java

import java.awt.BorderLayout;import java.awt.Color;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JOptionPane;import javax.swing.JPanel;import javax.swing.JTextField;import javax.swing.border.TitledBorder;public class Jisuanqi extends JFrame implements ActionListener{    private JTextField reasult;    private JButton btn1,btn2,btn3,btn4,btn5,btn6,btn7,btn8,btn9,btn0,                btnAC,btnAdd,btnSub,btnReasult,btnD,                btnAbout,btnCancel;    private boolean add,sub,end,s,c;    private String str;    private double num1,num2;    public Jisuanqi(){        JPanel p1=new JPanel();        JPanel p2=new JPanel();        JPanel p3=new JPanel();        TitledBorder tb=new TitledBorder("OutPut");tb.setTitleColor(Color.YELLOW);            btnAbout=new JButton("Producer");        btnCancel=new JButton("Close");        btnCancel.addActionListener(new ActionListener(){            public void actionPerformed(ActionEvent ee){                System.exit(0);            }        });        btnAbout.addActionListener(new ActionListener(){            public void actionPerformed(ActionEvent ee){                JOptionPane.showMessageDialog(null, "刘道广", "制作人",JOptionPane.INFORMATION_MESSAGE);            }        });        p3.add(btnAbout);        p3.add(btnCancel);                reasult = new JTextField("0",20);        reasult.setEditable(false);        reasult.setHorizontalAlignment(JTextField.RIGHT);        reasult.setForeground(Color.BLUE);                p1.setBorder(tb);        p1.add(reasult);        btn0=new JButton("0"); btn0.addActionListener(this);        btn1=new JButton("1");   btn1.addActionListener(this);        btn2=new JButton("2");   btn2.addActionListener(this);        btn3=new JButton("3");   btn3.addActionListener(this);         btn4=new JButton("4");   btn4.addActionListener(this);        btn5=new JButton("5");   btn5.addActionListener(this);        btn6=new JButton("6");   btn6.addActionListener(this);        btn7=new JButton("7");   btn7.addActionListener(this);        btn8=new JButton("8");   btn8.addActionListener(this);        btn9=new JButton("9");   btn9.addActionListener(this);        btnD=new JButton(".");     btnD.addActionListener(this); btnD.setForeground(Color.GREEN);        btnAC=new JButton("AC"); btnAC.addActionListener(this); btnAC.setBackground(Color.RED);        btnAdd=new JButton("+"); btnAdd.addActionListener(this); btnAdd.setForeground(Color.CYAN);        btnSub=new JButton("-"); btnSub.addActionListener(this); btnSub.setForeground(Color.CYAN);        btnReasult=new JButton("="); btnReasult.addActionListener(this); btnReasult.setForeground(Color.RED);                p2.add(btn1);p2.add(btn2);p2.add(btn3);p2.add(btn4);p2.add(btn5);        p2.add(btn6);p2.add(btn7);p2.add(btn8);p2.add(btn9);p2.add(btn0);        p2.add(btnD);p2.add(btnAC);p2.add(btnAdd);p2.add(btnSub);p2.add(btnReasult);        p2.setLayout(new GridLayout(5,3));                add(p1,BorderLayout.NORTH);        add(p2,BorderLayout.CENTER);        add(p3,BorderLayout.SOUTH);    }    public void num(int i){        String s=null;        s=String.valueOf(i);        if(end){            reasult.setText("0");            end=false;        }        if((reasult.getText()).equals("0")){            reasult.setText(s);        }        else{            str=reasult.getText()+s;            reasult.setText(str);        }    }    public void actionPerformed(ActionEvent e){        if(e.getSource()==btn1) num(1);        else if(e.getSource()==btn2) num(2);        else if(e.getSource()==btn3) num(3);        else if(e.getSource()==btn4) num(4);        else if(e.getSource()==btn5) num(5);        else if(e.getSource()==btn6) num(6);        else if(e.getSource()==btn7) num(7);        else if(e.getSource()==btn8) num(8);        else if(e.getSource()==btn9) num(9);        else if(e.getSource()==btn0) num(0);        else if(e.getSource()==btnAdd){            sign(1);            btnD.setEnabled(true);        }        else if(e.getSource()==btnSub){            sign(2);            btnD.setEnabled(true);        }        else if(e.getSource()==btnAC){            btnD.setEnabled(true);            reasult.setText("0");        }        else if(e.getSource()==btnD){            str=reasult.getText();            str+='.';            reasult.setText(str);            btnD.setEnabled(false);        }        else if(e.getSource()==btnReasult){            btnD.setEnabled(true);            num2=Double.parseDouble(reasult.getText());            if(add){                num1=num1+num2;            }            else if(sub){                num1=num1-num2;            }            reasult.setText(String.valueOf(num1));            end=true;        }    }    public void sign(int s){        if(s==1){            add=true;            sub=false;                    }        else if(s==2){            add=false;            sub=true;                    }                num1=Double.parseDouble(reasult.getText());        end=true;    }    public static void main(String[] args){        Jisuanqi j=new Jisuanqi();        j.setTitle("+/-简易计算器");        j.setLocation(500, 280);        j.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        j.setResizable(false);        j.pack();        j.setVisible(true);    }}