利用绝对布局制作两个数加减乘除的简易计算器

import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

public class ZC extends JFrame
{
public ZC()
{
setTitle("简易计算器");
setLayout(null);
setBounds(0,0,400,400);
@SuppressWarnings("unused")
Container c=getContentPane();//建立容器
JLabel a1=new JLabel("第一个数");//建立标签
JLabel a2=new JLabel("第二个数");
JLabel a3=new JLabel("结果");
JButton b1=new JButton("+");//建立按钮
JButton b2=new JButton("-");
JButton b3=new JButton("*");
JButton b4=new JButton("/");
b1.setBounds(70,220,50,30);//设置按钮大小
b2.setBounds(140,220,50,30);
b3.setBounds(210,220,50,30);
b4.setBounds(280,220,50,30);
a1.setBounds(10,30,100,30);
a2.setBounds(10,80,100,30);
a3.setBounds(10,130,100,30);
JTextField t1=new JTextField("请输入第一个数");
JTextField t2=new JTextField("请输入第二个数");
JTextField t3=new JTextField("结果");
t1.setBounds(100,30,150,30);
t2.setBounds(100,80,150,30);
t3.setBounds(100,130,150,30);
c.add(a1);
c.add(a2);
c.add(a3);
c.add(t1);
c.add(t2);
c.add(t3);
c.add(b1);
c.add(b2);
c.add(b3);
c.add(b4);
class jia implements ActionListener//加法
{
public void actionPerformed(ActionEvent c)
{
int a =Integer.parseInt(t1.getText());//获取t1输入的内容
int b =Integer.parseInt(t2.getText());//获取t2输入的内容
String a1=Integer.toString(a+b);
t3.setText(a1);//在t3中输出结果
}
}
class jian implements ActionListener//减法
{
public void actionPerformed(ActionEvent c)
{
int a =Integer.parseInt(t1.getText());
int b =Integer.parseInt(t2.getText());
String a1=Integer.toString(a-b);
t3.setText(a1);
}
}
class cheng implements ActionListener//乘
{
public void actionPerformed(ActionEvent c)
{
int a =Integer.parseInt(t1.getText());
int b =Integer.parseInt(t2.getText());
String a1=Integer.toString(a*b);
t3.setText(a1);
}
}
class chu implements ActionListener//除
{
public void actionPerformed(ActionEvent c)
{
int a =Integer.parseInt(t1.getText());
int b =Integer.parseInt(t2.getText());
double a1=a;
double b1=b;
String z=Double.toString(a1/b1);
t3.setText(z);
}
}
b1.addActionListener(new jia());
b2.addActionListener(new jian());
b3.addActionListener(new cheng());
b4.addActionListener(new chu());
setVisible(true);


}

public static void main(String[] args)
{
new ZC();

}

}