java代码编写计算器

package shx;

import java.awt.BorderLayout;

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.JPanel;

import javax.swing.JTextField;  

public class Jsq implements ActionListener { 
private JFrame frame;
private JButton[] bus;  
private JTextField jtx;  
private JButton bu;   
private char[] strs; 
private String d_one = "";  
private String operator;  
public static void main(String[] args) {  
new Jsq(); 
}

public Jsq() { 
frame = new JFrame("计算器"); 
jtx = new JTextField(14);  
bus = new JButton[16];   
strs = "789/456*123-0.+=".toCharArray();   
for (int i = 0; i < 16; i++) {  
bus[i] = new JButton(strs[i] + "");  
bus[i].addActionListener(this);  
} 
bu = new JButton("C");  
bu.addActionListener(this);  
init();  } 

public void init() {
JPanel jp1 = new JPanel(); 
jp1.add(jtx);   jp1.add(bu); 
frame.add(jp1, BorderLayout.NORTH);  
JPanel jp2 = new JPanel();   
jp2.setLayout(new GridLayout(4, 4));  
for (int i = 0; i < 16; i++) {  
jp2.add(bus[i]);  
}   
frame.add(jp2, BorderLayout.CENTER);  
frame.pack();  
frame.setLocation(300, 400);  
frame.setVisible(true);  
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
}   

public void actionPerformed(ActionEvent arg0) {  

String conn = arg0.getActionCommand();  
  
if ("C".equals(conn)) { 

  d_one = "";   

  operator = "";  

  jtx.setText("");   

  return;   

  }
 
if(".".equals(conn)){  
return;   
}   

if (("+-*/".indexOf(conn)) != -1) { 
if("".equals(d_one) && "".equals(jtx.getText())) 
return; 
d_one = jtx.getText();    operator = conn;  
jtx.setText("");    
return;  
}   

if ("=".equals(conn)) { 
if("".equals(d_one) && "".equals(jtx.getText()))
return;  
double db = 0; 
if ("+".equals(operator)) {  
db = Double.parseDouble(d_one)       + Double.parseDouble(jtx.getText());  
jtx.setText(db + "");  
}
if ("-".equals(operator)) {  
db = Double.parseDouble(d_one)       - Double.parseDouble(jtx.getText()); 
jtx.setText(db + "");   
}
if ("*".equals(operator)) { 
db = Double.parseDouble(d_one)  * Double.parseDouble(jtx.getText());  
jtx.setText(db + "");   
}  
if ("/".equals(operator)) { 
db = Double.parseDouble(d_one)       / Double.parseDouble(jtx.getText()); 
jtx.setText(db + ""); 
}   
d_one = db + ""; 
return;
} 

 
jtx.setText(jtx.getText() + conn);  
} 

}