简单计算器的实现(awt技术)

package homework;import java.awt.*;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;public class Calculater extends Frame implements ActionListener{    TextField tf=new TextField(30);    Panel p=new Panel();    Button b1 = new Button("1");    Button b2 = new Button("2");    Button b3 = new Button("3");    Button b4 = new Button("4");    Button b5 = new Button("5");     Button b6 = new Button("6");    Button b7 = new Button("7");    Button b8 = new Button("8");    Button b9= new Button("9");    Button b10 = new Button("0");    Button b11 = new Button("+");     Button b12 = new Button("-");     Button b13 = new Button("*");     Button b14 = new Button("/");     Button b15 = new Button("=");     Button b16 = new Button("C");     private String op = "";        private String str = "";        public String getOp()    {        return op;    }        public void setOp(String op)    {        this.op = op;    }        public String getStr()    {        return str;    }        public void setStr(String str)    {        this.str = str;    }    public Calculater(String name)    {      super(name);      this.b1.addActionListener(this);      this.b2.addActionListener(this);      this.b3.addActionListener(this);      this.b4.addActionListener(this);      this.b5.addActionListener(this);      this.b6.addActionListener(this);      this.b7.addActionListener(this);      this.b8.addActionListener(this);      this.b9.addActionListener(this);      this.b10.addActionListener(this);      this.b11.addActionListener(this);      this.b12.addActionListener(this);      this.b13.addActionListener(this);      this.b14.addActionListener(this);      this.b15.addActionListener(this);      this.b16.addActionListener(this);      this.setLayout(new BorderLayout());      this.add(tf,BorderLayout.NORTH);      this.add(p,BorderLayout.CENTER);      this.p.setLayout(new GridLayout(4,4));      this.p.add(b7);      this.p.add(b8);      this.p.add(b9);      this.p.add(b13);      this.p.add(b4);      this.p.add(b5);      this.p.add(b6);      this.p.add(b12);      this.p.add(b1);      this.p.add(b2);      this.p.add(b3);      this.p.add(b11);      this.p.add(b10);       this.p.add(b16);      this.p.add(b15);      this.p.add(b14);      this.setSize(400, 300);      this.addWindowListener(new WindowAdapter()      {          public void windowClosing(WindowEvent e)          {              System.exit(0);          }      });      this.setVisible(true);    }            public static void main(String[] args)    {        new Calculater("Calculater").setResizable(false);    }     @Override    public void actionPerformed(ActionEvent e)    {        String command = e.getActionCommand();        if("0".equals(command))        {          this.setStr(str+="0");          this.tf.setText(str);        }                 if("1".equals(command))        {            this.setStr(str+="1");            this.tf.setText(str);        }        if("2".equals(command))        {              this.setStr(str+="2");        this.tf.setText(str);        }                if("3".equals(command))        {            this.setStr(str+="3");            this.tf.setText(str);        }                if("4".equals(command))        {            this.setStr(str+="4");            this.tf.setText(str);        }                if("5".equals(command))        {            this.setStr(str+="5");            this.tf.setText(str);        }                if("6".equals(command))        {            this.setStr(str+="6");            this.tf.setText(str);        }                if("7".equals(command))        {            this.setStr(str+="7");            this.tf.setText(str);        }                if("8".equals(command))        {            this.setStr(str+="8");            this.tf.setText(str);        }                if("9".equals(command))        {            this.setStr(str+="9");            this.tf.setText(str);        }                        if("+".equals(command))        {            this.setStr(str+="+");            this.setOp("+");            this.tf.setText(str);        }                if("-".equals(command))        {            this.setStr(str+="-");            this.setOp("-");            this.tf.setText(str);        }                if("*".equals(command))        {            this.setStr(str+="*");            this.setOp("*");            this.tf.setText(str);        }                if("/".equals(command))        {            this.setStr(str+="/");            this.setOp("/");            this.tf.setText(str);        }                if("=".equals(command))        {           String result[]=this.getStr().split("\\"+this.getOp());           int a=Integer.parseInt(result[0]);           int b=Integer.parseInt(result[1]);           int d=0;                if(op.equals("+"))           {               d=a+b;               this.tf.setText(new Integer(d).toString());                          }           else if(op.equals("-"))           {               d=a-b;               this.tf.setText(new Integer(d).toString());           }           else if(op.equals("*"))           {               d=a*b;               this.tf.setText(new Integer(d).toString());           }           else  if(op.equals("/"))           {                    double dd=(double)a/(double)b;               this.tf.setText(dd+"");           }        }                if("C".equals(command))        {           this.tf.setText("");                      this.setStr("");           this.setOp("");        }                    }}