java计算机代码. java计算机代码怎么设置小数点只能打一个

跪求简单计算器的java代码，要入门级的编程~~

//////////////////////////这个很简单,方法也差不多////////////埋举掘////////

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import javax.swing.*;

import java.awt.event.*;

import java.awt.*;

public class Calculator extends JFrame implements ActionListener

{

///////////////菜单

JMenuBar mb;

JMenu mEdit,mFind,mHelp;

JMenuItem mEditCopy,mEditPaste;

JMenuItem mFindStandarded,mFindScience,mFindGroup;

JMenuItem mHelpTopic,mHelpAbout;

JPanel pan;

/////////////按钮

JTextField tf;

JButton butnull;

JButton butBackspace,butCE,butC;

JButton butMC,butMR,butMS,butM;

JButton but1,but2,but3,but4,but5,but6,but7,but8,but9,but0;

JButton butChu,butSqrt,butCheng,butYu,butJian,but1x,butDot,butJia,butEqual,butJJ;

Calculator()

{

mb =new JMenuBar();

mEdit =new JMenu("编辑(E)");

mEdit.setMnemonic('E');

mFind =new JMenu("查看(F)");

mFind.setMnemonic('F');

mHelp =new JMenu("帮助(H)");

mFind.setMnemonic('H');

mEditCopy =new JMenuItem("复制(C)");

mEditCopy.setMnemonic('C');

mEditPaste =new JMenuItem("粘贴(P)");

mEditCopy.setMnemonic('P');

mFindStandarded=new JMenuItem("标准型(T)");

mFindStandarded.setMnemonic('T');

mFindScience=new JMenuItem("科学型(S)");

mFindScience.setMnemonic('S');

mFindGroup =new JMenuItem("数字分组(I)");

mFindGroup.setMnemonic('I');

mHelpTopic =new JMenuItem("帮助主题(H)");

mHelpTopic.setMnemonic('H');

mHelpAbout =new JMenuItem("关于我们弯核(A)");

mHelpAbout.setMnemonic('A');

////////////////////////////添加mb组件beginning

mb.add(mEdit);

mb.add(mFind);

mb.add(mHelp);

mEdit.add(mEditCopy);

mEdit.add(mEditPaste);

mFind.add(mFindStandarded);

mFind.add(mFindScience);

mFind.add(mFindGroup);

mHelp.add(mHelpTopic);

mHelp.add(mHelpAbout);//////////////ending

////////////////////////***创建计算机按钮***////////////////////

Color red =new Color(250,0,0);

Color green =new Color(0,127,0);

butnull =new JButton("?");

butnull.setForeground(red);

butnull.addActionListener(this);

butBackspace =new JButton("Backspace");

butBackspace.setForeground(green);

butCE =new JButton("答乱CE");

butCE.setForeground(green);

butC =new JButton("C");

butC.addActionListener(this);

butC.setForeground(red);

butMC =new JButton("MC");

butMC.setForeground(green);

butMR =new JButton("MR");

butMR.setForeground(green);

butMS =new JButton("MS");

butMS.setForeground(green);

butM =new JButton("M+");

butM.setForeground(green);

butChu =new JButton("/");

butChu.addActionListener(this);

butChu.setForeground(red);

butCheng =new JButton("*");

butCheng.addActionListener(this);

butCheng.setForeground(red);

butJian =new JButton("-");

butJian.addActionListener(this);

butJian.setForeground(red);

butJia =new JButton("+");

butJia.addActionListener(this);

butJia.setForeground(red);

butEqual =new JButton("=");

butEqual.addActionListener(this);

butEqual.setForeground(red);

Color blue =new Color(0,0,250);

butSqrt =new JButton("sqrt");

butSqrt.setForeground(green);

butYu =new JButton("%");

butYu.setForeground(green);

but1x =new JButton("1/x");

but1x.setForeground(green);

butDot =new JButton(".");

butDot.setForeground(blue);

butDot.addActionListener(this);

butJJ =new JButton("+/-");

butJJ.setForeground(blue);

butJJ.addActionListener(this);

but1 =new JButton("1");

but1.addActionListener(this);

but1.setForeground(blue);

but2 =new JButton("2");

but2.addActionListener(this);

but2.setForeground(blue);

but3 =new JButton("3");

but3.addActionListener(this);

but3.setForeground(blue);

but4 =new JButton("4");

but4.addActionListener(this);

but4.setForeground(blue);

but5 =new JButton("5");

but5.addActionListener(this);

but5.setForeground(blue);

but6 =new JButton("6");

but6.addActionListener(this);

but6.setForeground(blue);

but7 =new JButton("7");

but7.addActionListener(this);

but7.setForeground(blue);

but8 =new JButton("8");

but8.addActionListener(this);

but8.setForeground(blue);

but9 =new JButton("9");

but9.addActionListener(this);

but9.setForeground(blue);

but0 =new JButton("0");

but0.addActionListener(this);

but0.setForeground(blue);///////////////////////////////ending

pan =new JPanel(null);//创建最大的panel

tf =new JTextField("0");//输入显示框

tf.setBounds(5,0,337,25);//显示框设置大小位置

tf.setBackground(Color.white);

tf.setHorizontalAlignment(JTextField.RIGHT);//输入框设置位子居右显示

tf.setEditable(false);

JPanel pa=new JPanel(new BorderLayout());//所有按钮的panel

pa.setBounds(5,35,340,240);

JPanel pp=new JPanel(new BorderLayout());//null,MC,MR,MS,M+的panel;pa的西

JPanel aa=new JPanel(new BorderLayout());//其余所有Button的panel;pa的中

JPanel p =new JPanel(new GridLayout(4,1));//MC,MR,MS,M+的Panel，pp的中 北是一个butnull

JPanel a =new JPanel(new GridLayout(1,3));//backspace,ce,c的panel，aa的北

JPanel a2=new JPanel(new GridLayout(4,5));//其余的button的panel，aa的中

pa.add(pp,BorderLayout.WEST);

pa.add(aa,BorderLayout.CENTER);

pp.add(butnull,BorderLayout.NORTH);

pp.add(p,BorderLayout.CENTER);

p.add(butMC);

p.add(butMR);

p.add(butMS);

p.add(butM);

aa.add(a,BorderLayout.NORTH);

aa.add(a2,BorderLayout.CENTER);

a.add(butBackspace);

a.add(butCE);

a.add(butC);

a2.add(but7);

a2.add(but8);

a2.add(but9);

a2.add(butChu);

a2.add(butSqrt);

a2.add(but4);

a2.add(but5);

a2.add(but6);

a2.add(butCheng);

a2.add(butYu);

a2.add(but1);

a2.add(but2);

a2.add(but3);

a2.add(butJian);

a2.add(but1x);

a2.add(but0);

a2.add(butJJ);

a2.add(butDot);

a2.add(butJia);

a2.add(butEqual);

this.add(pan);

pan.add(tf);

pan.add(pa);

this.setTitle("我的计算器");

this.setJMenuBar(mb);

this.setBounds(200,300,353,330);//设置窗口大小

this.setResizable(false);

this.setVisible(true);

}

public static void main(String args[])

{

try

{

UIManager.setLookAndFeel(

UIManager.getSystemLookAndFeelClassName());

}

catch (Exception ex)

{

ex.printStackTrace();

}

new Calculator();

}

////////////////////********以下是监听设置和运算*******///////////////////

boolean b=true;//初始值设置为真未点运算符号

String fuhao="";//保存最后一次运算符号，用于进行上次结果的运算

String lastCommand="";//保存按等号前的最后的运算符号

double lastValue=0.0;//保存按等号钱的最后的输入框里的值

double value=0.0;//原值，当你点完运算符的时候计算之前的值

double fuzhi=0.0;

public void actionPerformed(ActionEvent click)/////////////////////行为监听设置

{

if(click.getSource()==butJJ)

{

fuzhi=Double.parseDouble(tf.getText());

if(tf.getText().equals("0")||tf.getText().equals("0."))

{

boolean b=true;

String fuhao="";

double value=0.0;

tf.setText("0");

}

else if(fuzhi0)

{

tf.setText((-fuzhi)+"");

}

else

{

tf.setText("-"+tf.getText());

}

}

if(click.getSource()==butnull)

{

tf.setText("本计算器版权所有归青软培训--胡迅--2008年10月18日著 ");

}

if(click.getSource()==butC)

{

tf.setText("0");

lastCommand="";

lastValue=0.0;

b=true;

fuhao="";

value=0.0;

}

if(click.getSource()==but1)

{

if(b==false)

{

tf.setText("1");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("1");

}

else

{

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

}

}

if(click.getSource()==but2)

{

if(b==false)

{

tf.setText("2");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("2");

}

else

{

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

}

}

if(click.getSource()==but3)

{

if(b==false)

{

tf.setText("3");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("3");

}

else

{

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

}

}

if(click.getSource()==but4)

{

if(b==false)

{

tf.setText("4");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("4");

}

else

{

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

}

}

if(click.getSource()==but5)

{

if(b==false)

{

tf.setText("5");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("5");

}

else

{

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

}

}

if(click.getSource()==but6)

{

if(b==false)

{

tf.setText("6");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("6");

}

else

{

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

}

}

if(click.getSource()==but7)

{

if(b==false)

{

tf.setText("7");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("7");

}

else

{

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

}

}

if(click.getSource()==but8)

{

if(b==false)

{

tf.setText("8");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("8");

}

else

{

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

}

}

if(click.getSource()==but9)

{

if(b==false)

{

tf.setText("9");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("9");

}

else

{

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

}

}

if(click.getSource()==but0)

{

if(b==false)

{

tf.setText("0");

b=true;

}

else if(tf.getText().equals("0"))

{

tf.setText("0");

}

else

{

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

}

}

if(click.getSource()==butDot)

{

/////////code/////////////////////////////////////////////////////////////////////////////////////////////////////////???

int izhi=Integer.parseInt(tf.getText());

double dzhi=Double.parseDouble(tf.getText());

if(tf.getText().equals("0"))

{

tf.setText("0.");

}

else

{

if(tf.getText().equals("0."))

{

tf.setText("0.");

}

else

{

if(dzhi0)

{

izhi=izhi;

dzhi=dzhi;

if(dzhi==izhi)

{

tf.setText(tf.getText()+".");

}

}

else

{

izhi=-izhi;

dzhi=-dzhi;

if(dzhi==izhi)

{

tf.setText(tf.getText()+".");

}

}

}

}

}

if(click.getSource()==butJia)///////////////////////////////////////////////"+"

{

if(tf.getText().equals("0"))

{

}

else if(fuhao=="")

{

double tfvaluejia;

tfvaluejia=Double.parseDouble(tf.getText());

value=tfvaluejia;

tf.setText(""+value);

b=false;

fuhao="+";

}

else if(fuhao=="*")

{

double tfvalueCheng;

tfvalueCheng=Double.parseDouble(tf.getText());

value=value*tfvalueCheng;

tf.setText(""+value);

b=false;

}

else if(fuhao=="/")

{

double tfvalueChu;

tfvalueChu=Double.parseDouble(tf.getText());

value=value/tfvalueChu;

tf.setText(""+value);

b=false;

}

else if(fuhao=="-")

{

double tfvaluejian;

tfvaluejian=Double.parseDouble(tf.getText());

value=value-tfvaluejian;

tf.setText(""+value);

b=false;

}

else if(fuhao=="=")

{

double tfvaluejia;

tfvaluejia=Double.parseDouble(tf.getText());

value=tfvaluejia;

b=false;

}

else

{

double tfvaluejia;

tfvaluejia=Double.parseDouble(tf.getText());//2

value=value+tfvaluejia;

tf.setText(""+value);

b=false;

}

lastValue=Double.parseDouble(tf.getText());

fuhao="+";

lastCommand="+";

}

if(click.getSource()==butCheng)////////////////////////////////////////////////////////////"*"

{

if(tf.getText().equals("0"))

{

}

else if(fuhao=="")

{

double tfvalueCheng;

tfvalueCheng=Double.parseDouble(tf.getText());

value=tfvalueCheng;

tf.setText(""+value);

b=false;

fuhao="*";

}

else if(fuhao=="+")

{

double tfvaluejia;

tfvaluejia=Double.parseDouble(tf.getText());

value=value+tfvaluejia;

tf.setText(""+value);

b=false;

}

else if(fuhao=="/")

{

double tfvalueChu;

tfvalueChu=Double.parseDouble(tf.getText());

value=value/tfvalueChu;

tf.setText(""+value);

b=false;

}

else if(fuhao=="-")

{

double tfvaluejian;

tfvaluejian=Double.parseDouble(tf.getText());

value=value-tfvaluejian;

tf.setText(""+value);

b=false;

}

else if(fuhao=="=")

{

double tfvalueCheng;

tfvalueCheng=Double.parseDouble(tf.getText());

value=tfvalueCheng;

b=false;

}

else

{

double tfvalueCheng;

tfvalueCheng=Double.parseDouble(tf.getText());

value=value*tfvalueCheng;

tf.setText(""+value);

b=false;

}

lastValue=Double.parseDouble(tf.getText());

fuhao="*";

lastCommand="*";

}

if(click.getSource()==butChu)//////////////////////////////////////////////"/"

{

if(tf.getText().equals("0"))

{

}

else if(fuhao=="")

{

double tfvalueChu;

tfvalueChu=Double.parseDouble(tf.getText());

value=tfvalueChu;

tf.setText(""+value);

b=false;

fuhao="/";

}

else if(fuhao=="+")

{

double tfvaluejia;

tfvaluejia=Double.parseDouble(tf.getText());

value=value+tfvaluejia;

tf.setText(""+value);

b=false;

}

else if(fuhao=="*")

{

double tfvalueCheng;

tfvalueCheng=Double.parseDouble(tf.getText());

value=value*tfvalueCheng;

tf.setText(""+value);

b=false;

}

else if(fuhao=="-")

{

double tfvaluejian;

tfvaluejian=Double.parseDouble(tf.getText());

value=value-tfvaluejian;

tf.setText(""+value);

b=false;

}

else if(fuhao=="=")

{

double tfvalueCheng;

tfvalueCheng=Double.parseDouble(tf.getText());

value=tfvalueCheng;

b=false;

}

else

{

double tfvalueChu;

tfvalueChu=Double.parseDouble(tf.getText());

value=value/tfvalueChu;

tf.setText(""+value);

b=false;

}

lastValue=Double.parseDouble(tf.getText());

fuhao="/";

lastCommand="/";

}

if(click.getSource()==butJian)////////////////////////////////////////////////////////////////////////"-"

{

if(tf.getText().equals("0"))

{

}

else if(fuhao=="")

{

double tfvaluejian;

tfvaluejian=Double.parseDouble(tf.getText());

value=tfvaluejian;

tf.setText(""+value);

b=false;

fuhao="/";

}

else if(fuhao=="+")

{

double tfvaluejia;

tfvaluejia=Double.parseDouble(tf.getText());

value=value+tfvaluejia;

tf.setText(""+value);

b=false;

}

else if(fuhao=="*")

{

double tfvalueCheng;

tfvalueCheng=Double.parseDouble(tf.getText());

value=value*tfvalueCheng;

tf.setText(""+value);

b=false;

}

else if(fuhao=="/")

{

double tfvalueChu;

tfvalueChu=Double.parseDouble(tf.getText());

value=value/tfvalueChu;

tf.setText(""+value);

b=false;

}

else if(fuhao=="=")

{

double tfvalueCheng;

tfvalueCheng=Double.parseDouble(tf.getText());

value=tfvalueCheng;

b=false;

}

else

{

double tfvaluejian;

tfvaluejian=Double.parseDouble(tf.getText());

value=value-tfvaluejian;

tf.setText(""+value);

b=false;

}

lastValue=Double.parseDouble(tf.getText());

fuhao="-";

lastCommand="-";

}

if(click.getSource()==butEqual)//////////////////////////////////////////"="

{

if(tf.getText().equals("0"))

{

}

if(fuhao=="+")

{

double tfvaluejia;

tfvaluejia=Double.parseDouble(tf.getText());

value=value+tfvaluejia;

tf.setText(""+value);

b=false;

}

else if(fuhao=="*")

{

double tfvalueCheng;

tfvalueCheng=Double.parseDouble(tf.getText());

value=value*tfvalueCheng;

tf.setText(""+value);

b=false;

}

else if(fuhao=="/")

{

double tfvalueChu;

tfvalueChu=Double.parseDouble(tf.getText());

value=value/tfvalueChu;

tf.setText(""+value);

b=false;

}

else if(fuhao=="-")

{

double tfvaluejian;

tfvaluejian=Double.parseDouble(tf.getText());

value=value-tfvaluejian;

tf.setText(""+value);

b=false;

}

else if(fuhao=="=")

{

if(lastCommand=="+")

{

value = value +lastValue;

tf.setText(""+value);

b=false;

}

else if(lastCommand=="-")

{

value = value - lastValue;

tf.setText(""+value);

b=false;

}

if(lastCommand=="*")

{

value = value *lastValue;

tf.setText(""+value);

b=false;

}

if(lastCommand=="/")

{

value = value /lastValue;

tf.setText(""+value);

b=false;

}

}

fuhao="=";

}

}

}