用NetBeans写的一个简单计算器，源码如下

/*

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 * To change this template file, choose Tools | Templates

 * and open the template in the editor.

 */

package com.ui;

import java.util.Arrays;

import java.util.logging.Level;

import java.util.logging.Logger;

import javax.script.ScriptEngine;

import javax.script.ScriptEngineManager;

import javax.script.ScriptException;

/**

 *

 * @author Administrator

 */

public class CalculatorUI extends javax.swing.JFrame {

    /**

     * Creates new form CalculatorUI

     */

    public CalculatorUI() {

        initComponents();

    }

    /**

     * This method is called from within the constructor to initialize the form.

     * WARNING: Do NOT modify this code. The content of this method is always

     * regenerated by the Form Editor.

     */

    @SuppressWarnings("unchecked")

    // <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents

    private void initComponents() {

        jLayeredPane1 = new javax.swing.JLayeredPane();

        jPanel1 = new javax.swing.JPanel();

        jTextField2 = new javax.swing.JTextField();

        jSeparator1 = new javax.swing.JSeparator();

        jButton1 = new javax.swing.JButton();

        jButton2 = new javax.swing.JButton();

        jButton3 = new javax.swing.JButton();

        jButton4 = new javax.swing.JButton();

        jButton5 = new javax.swing.JButton();

        jButton6 = new javax.swing.JButton();

        jButton7 = new javax.swing.JButton();

        jButton8 = new javax.swing.JButton();

        jButton9 = new javax.swing.JButton();

        jButton10 = new javax.swing.JButton();

        jButton11 = new javax.swing.JButton();

        jButton12 = new javax.swing.JButton();

        jButton14 = new javax.swing.JButton();

        jButton15 = new javax.swing.JButton();

        jButton16 = new javax.swing.JButton();

        jButton17 = new javax.swing.JButton();

        jButton18 = new javax.swing.JButton();

        jButton19 = new javax.swing.JButton();

        jLabel1 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        setBackground(new java.awt.Color(102, 255, 51));

        setMaximumSize(new java.awt.Dimension(32767, 32767));

        setPreferredSize(new java.awt.Dimension(261, 327));

        jLayeredPane1.setOpaque(true);

        jPanel1.setAlignmentX(0.0F);

        jPanel1.setAlignmentY(0.0F);

        jPanel1.setOpaque(false);

        jTextField2.setEditable(false);

        jTextField2.setFont(new java.awt.Font("宋体", 0, 18)); // NOI18N

        jTextField2.setHorizontalAlignment(javax.swing.JTextField.RIGHT);

        jTextField2.setText("0");

        jButton1.setText("2");

        jButton1.addMouseListener(new java.awt.event.MouseAdapter() {

            public void mouseReleased(java.awt.event.MouseEvent evt) {

                jButton1MouseReleased(evt);

            }

        });

        jButton1.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton1ActionPerformed(evt);

            }

        });

        jButton2.setText("1");

        jButton2.addMouseListener(new java.awt.event.MouseAdapter() {

            public void mouseReleased(java.awt.event.MouseEvent evt) {

                jButton2MouseReleased(evt);

            }

        });

        jButton2.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton2ActionPerformed(evt);

            }

        });

        jButton3.setText("4");

        jButton3.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton3ActionPerformed(evt);

            }

        });

        jButton3.addKeyListener(new java.awt.event.KeyAdapter() {

            public void keyTyped(java.awt.event.KeyEvent evt) {

                jButton3KeyTyped(evt);

            }

        });

        jButton4.setText("5");

        jButton4.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton4ActionPerformed(evt);

            }

        });

        jButton5.setText("6");

        jButton5.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton5ActionPerformed(evt);

            }

        });

        jButton6.setText("7");

        jButton6.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton6ActionPerformed(evt);

            }

        });

        jButton7.setText("8");

        jButton7.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton7ActionPerformed(evt);

            }

        });

        jButton8.setText("3");

        jButton8.addMouseListener(new java.awt.event.MouseAdapter() {

            public void mouseReleased(java.awt.event.MouseEvent evt) {

                jButton8MouseReleased(evt);

            }

        });

        jButton8.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton8ActionPerformed(evt);

            }

        });

        jButton9.setText("9");

        jButton9.addMouseListener(new java.awt.event.MouseAdapter() {

            public void mouseReleased(java.awt.event.MouseEvent evt) {

                jButton9MouseReleased(evt);

            }

        });

        jButton9.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton9ActionPerformed(evt);

            }

        });

        jButton10.setText("0");

        jButton10.addMouseListener(new java.awt.event.MouseAdapter() {

            public void mouseReleased(java.awt.event.MouseEvent evt) {

                jButton10MouseReleased(evt);

            }

        });

        jButton10.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton10ActionPerformed(evt);

            }

        });

        jButton11.setFont(new java.awt.Font("宋体", 0, 18)); // NOI18N

        jButton11.setText(".");

        jButton11.addMouseListener(new java.awt.event.MouseAdapter() {

            public void mouseReleased(java.awt.event.MouseEvent evt) {

                jButton11MouseReleased(evt);

            }

        });

        jButton11.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton11ActionPerformed(evt);

            }

        });

        jButton12.setText("+");

        jButton12.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton12ActionPerformed(evt);

            }

        });

        jButton14.setText("-");

        jButton14.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton14ActionPerformed(evt);

            }

        });

        jButton15.setText("/");

        jButton15.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton15ActionPerformed(evt);

            }

        });

        jButton16.setText("=");

        jButton16.addMouseListener(new java.awt.event.MouseAdapter() {

            public void mouseReleased(java.awt.event.MouseEvent evt) {

                jButton16MouseReleased(evt);

            }

        });

        jButton16.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton16ActionPerformed(evt);

            }

        });

        jButton17.setText("C");

        jButton17.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton17ActionPerformed(evt);

            }

        });

        jButton18.setText("←");

        jButton18.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton18ActionPerformed(evt);

            }

        });

        jButton19.setText("*");

        jButton19.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                jButton19ActionPerformed(evt);

            }

        });

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);

        jPanel1.setLayout(jPanel1Layout);

        jPanel1Layout.setHorizontalGroup(

            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addGroup(jPanel1Layout.createSequentialGroup()

                .addContainerGap()

                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                    .addComponent(jTextField2, javax.swing.GroupLayout.Alignment.TRAILING)

                    .addComponent(jSeparator1, javax.swing.GroupLayout.Alignment.TRAILING)

                    .addGroup(jPanel1Layout.createSequentialGroup()

                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                            .addGroup(jPanel1Layout.createSequentialGroup()

                                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                                    .addGroup(jPanel1Layout.createSequentialGroup()

                                        .addComponent(jButton2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)

                                        .addComponent(jButton1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                                        .addGap(4, 4, 4))

                                    .addComponent(jButton10, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))

                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)

                                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                                    .addGroup(jPanel1Layout.createSequentialGroup()

                                        .addComponent(jButton11, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)

                                        .addComponent(jButton12, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))

                                    .addGroup(jPanel1Layout.createSequentialGroup()

                                        .addComponent(jButton8, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                                        .addGap(13, 13, 13)

                                        .addComponent(jButton14, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))))

                            .addGroup(jPanel1Layout.createSequentialGroup()

                                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)

                                    .addComponent(jButton6, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                                    .addComponent(jButton3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))

                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)

                                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                                    .addGroup(jPanel1Layout.createSequentialGroup()

                                        .addComponent(jButton7, javax.swing.GroupLayout.PREFERRED_SIZE, 44, javax.swing.GroupLayout.PREFERRED_SIZE)

                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                                        .addComponent(jButton9)

                                        .addGap(19, 19, 19))

                                    .addGroup(jPanel1Layout.createSequentialGroup()

                                        .addComponent(jButton4, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                                        .addGap(14, 14, 14)

                                        .addComponent(jButton5, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                                        .addGap(15, 15, 15)))

                                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)

                                    .addComponent(jButton19, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                                    .addComponent(jButton15, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))))

                        .addGap(8, 8, 8)

                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                            .addGroup(jPanel1Layout.createSequentialGroup()

                                .addGap(2, 2, 2)

                                .addComponent(jButton18, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))

                            .addComponent(jButton17, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                            .addComponent(jButton16, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))))

        );

        jPanel1Layout.setVerticalGroup(

            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addGroup(jPanel1Layout.createSequentialGroup()

                .addContainerGap()

                .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, 47, javax.swing.GroupLayout.PREFERRED_SIZE)

                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)

                .addComponent(jSeparator1, javax.swing.GroupLayout.PREFERRED_SIZE, 18, javax.swing.GroupLayout.PREFERRED_SIZE)

                .addGap(18, 18, 18)

                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)

                    .addComponent(jButton15, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                    .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                        .addComponent(jButton6, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)

                        .addComponent(jButton7, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)

                        .addComponent(jButton9, javax.swing.GroupLayout.PREFERRED_SIZE, 39, javax.swing.GroupLayout.PREFERRED_SIZE))

                    .addComponent(jButton18, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE))

                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)

                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                    .addGroup(jPanel1Layout.createSequentialGroup()

                        .addComponent(jButton17, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)

                        .addGap(17, 17, 17)

                        .addComponent(jButton16, javax.swing.GroupLayout.PREFERRED_SIZE, 93, javax.swing.GroupLayout.PREFERRED_SIZE))

                    .addGroup(jPanel1Layout.createSequentialGroup()

                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                                .addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)

                                .addComponent(jButton4, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE))

                            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                                .addComponent(jButton5, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)

                                .addComponent(jButton19, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)))

                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)

                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                            .addComponent(jButton14, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.PREFERRED_SIZE, 32, javax.swing.GroupLayout.PREFERRED_SIZE)

                            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                                .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)

                                .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)

                                .addComponent(jButton8, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)))

                        .addGap(10, 10, 10)

                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                            .addComponent(jButton10, javax.swing.GroupLayout.PREFERRED_SIZE, 46, javax.swing.GroupLayout.PREFERRED_SIZE)

                            .addComponent(jButton11)

                            .addComponent(jButton12, javax.swing.GroupLayout.PREFERRED_SIZE, 29, javax.swing.GroupLayout.PREFERRED_SIZE)))))

        );

        jPanel1Layout.linkSize(javax.swing.SwingConstants.VERTICAL, new java.awt.Component[] {jButton11, jButton12, jButton14, jButton15, jButton19, jButton5, jButton8, jButton9});

        jLabel1.setIcon(new javax.swing.ImageIcon(getClass().getResource("/com/ui/2151263323.jpg"))); // NOI18N

        javax.swing.GroupLayout jLayeredPane1Layout = new javax.swing.GroupLayout(jLayeredPane1);

        jLayeredPane1.setLayout(jLayeredPane1Layout);

        jLayeredPane1Layout.setHorizontalGroup(

            jLayeredPane1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addGroup(jLayeredPane1Layout.createSequentialGroup()

                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)

                .addGap(0, 7, Short.MAX_VALUE))

            .addGroup(jLayeredPane1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                .addGroup(jLayeredPane1Layout.createSequentialGroup()

                    .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 264, javax.swing.GroupLayout.PREFERRED_SIZE)

                    .addGap(0, 0, Short.MAX_VALUE)))

        );

        jLayeredPane1Layout.setVerticalGroup(

            jLayeredPane1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addGroup(jLayeredPane1Layout.createSequentialGroup()

                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)

                .addGap(0, 7, Short.MAX_VALUE))

            .addGroup(jLayeredPane1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                .addComponent(jLabel1, javax.swing.GroupLayout.DEFAULT_SIZE, 301, Short.MAX_VALUE))

        );

        jLayeredPane1.setLayer(jPanel1, javax.swing.JLayeredPane.DEFAULT_LAYER);

        jLayeredPane1.setLayer(jLabel1, javax.swing.JLayeredPane.DEFAULT_LAYER);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());

        getContentPane().setLayout(layout);

        layout.setHorizontalGroup(

            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addGroup(layout.createSequentialGroup()

                .addComponent(jLayeredPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)

                .addGap(0, 0, Short.MAX_VALUE))

        );

        layout.setVerticalGroup(

            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addComponent(jLayeredPane1)

        );

        pack();

    }// </editor-fold>//GEN-END:initComponents

    private void jButton19ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton19ActionPerformed

        // TODO add your handling code here:

        setYSF("*");

    }//GEN-LAST:event_jButton19ActionPerformed

    private void jButton18ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton18ActionPerformed

        // TODO add your handling code here:

        //获得文本并赋值给strBuf

        StringBuffer strBuf = new StringBuffer(jTextField2.getText());

        //判断sreBuf的长度是否是1位

        if (strBuf.length() == 1) {

            //直接返回0

            jTextField2.setText("0");

        } else {

            //删除最后一位字符并还给文本框

            jTextField2.setText(strBuf.deleteCharAt(strBuf.length() - 1).toString());

        }

    }//GEN-LAST:event_jButton18ActionPerformed

    private void jButton17ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton17ActionPerformed

        // TODO add your handling code here:

        jTextField2.setText("0");

    }//GEN-LAST:event_jButton17ActionPerformed

    private void jButton16ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton16ActionPerformed

        // TODO add your handling code here:

        ScriptEngineManager manager = new ScriptEngineManager();

        ScriptEngine sc = manager.getEngineByName("js");

        Double result = null;

        try {

            result = (Double) sc.eval("(" + jTextField2.getText() + ")*1.0");

        } catch (ScriptException ex) {

            Logger.getLogger(CalculatorUI.class.getName()).log(Level.SEVERE, null, ex);

            jTextField2.setText("输入错误，按C重新输入");

        }

        jTextField2.setText(result.toString());

    }//GEN-LAST:event_jButton16ActionPerformed

    private void jButton16MouseReleased(java.awt.event.MouseEvent evt) {//GEN-FIRST:event_jButton16MouseReleased

        // TODO add your handling code here:

    }//GEN-LAST:event_jButton16MouseReleased

    private void jButton15ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton15ActionPerformed

        // TODO add your handling code here:

        setYSF("/");

    }//GEN-LAST:event_jButton15ActionPerformed

    private void jButton14ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton14ActionPerformed

        // TODO add your handling code here:

        setYSF("-");

    }//GEN-LAST:event_jButton14ActionPerformed

    private void jButton12ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton12ActionPerformed

        // TODO add your handling code here:

        setYSF("+");

    }//GEN-LAST:event_jButton12ActionPerformed

    private void jButton11ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton11ActionPerformed

        // TODO add your handling code here:

        String strTest = jTextField2.getText();

        StringBuffer strTest1 = new StringBuffer(jTextField2.getText());

        int lastR = strTest.length() - 1;

        char ch = strTest.charAt(lastR);

//如果显示框最后一位是小数点，则什么都不加

        if (ch == '.') {

            jTextField2.setText(strTest);

        } //如果显示框最后一位是运算符，则添加0.   

        else if (ch == '+' || ch == '-' || ch == '*' || ch == '/') {

            jTextField2.setText(strTest + "0.");

            //否则，则从后检查显示框中有没有运算符，如果有，就从运算符后开始检测有没有小数点，（如果没有则加.，否则什么都不干），

            //                                  ,如果没有运算符,则检测显示框中有没有小数点，（如果没有则加.，否则什么都不干）

            //取出当前显示的内容放到字符串变量strTest中

        } else if (strTest.lastIndexOf('+') != -1 || strTest.lastIndexOf('-') != -1 || strTest.lastIndexOf('*') != -1 || strTest.lastIndexOf('/') != -1) {

            int[] a = new int[]{strTest.lastIndexOf('+'), strTest.lastIndexOf('-'), strTest.lastIndexOf('*'), strTest.lastIndexOf('/')};

            Arrays.sort(a);

            String strNew = strTest.substring(a[3] + 1, lastR + 1);

            if (strNew.lastIndexOf('.') == -1) {

                strTest1.append('.');

                jTextField2.setText(strTest1.toString());

            } else {

                jTextField2.setText(strTest);

            }

        } else {

            if (strTest.lastIndexOf('.') == -1) {

                strTest1.append('.');

                jTextField2.setText(strTest1.toString());

            } else {

                jTextField2.setText(strTest);

            }

        }

    }//GEN-LAST:event_jButton11ActionPerformed

    private void jButton11MouseReleased(java.awt.event.MouseEvent evt) {//GEN-FIRST:event_jButton11MouseReleased

        // TODO add your handling code here:

    }//GEN-LAST:event_jButton11MouseReleased

    private void jButton10ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton10ActionPerformed

        // TODO add your handling code here:

        setNum("0");

    }//GEN-LAST:event_jButton10ActionPerformed

    private void jButton10MouseReleased(java.awt.event.MouseEvent evt) {//GEN-FIRST:event_jButton10MouseReleased

        // TODO add your handling code here:

    }//GEN-LAST:event_jButton10MouseReleased

    private void jButton9ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton9ActionPerformed

        // TODO add your handling code here:

        setNum("9");

    }//GEN-LAST:event_jButton9ActionPerformed

    private void jButton9MouseReleased(java.awt.event.MouseEvent evt) {//GEN-FIRST:event_jButton9MouseReleased

        // TODO add your handling code here:

    }//GEN-LAST:event_jButton9MouseReleased

    private void jButton8ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton8ActionPerformed

        // TODO add your handling code here:

        setNum("3");

    }//GEN-LAST:event_jButton8ActionPerformed

    private void jButton8MouseReleased(java.awt.event.MouseEvent evt) {//GEN-FIRST:event_jButton8MouseReleased

        // TODO add your handling code here:

    }//GEN-LAST:event_jButton8MouseReleased

    private void jButton7ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton7ActionPerformed

        // TODO add your handling code here:

        setNum("8");

    }//GEN-LAST:event_jButton7ActionPerformed

    private void jButton6ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton6ActionPerformed

        // TODO add your handling code here:

        setNum("7");

    }//GEN-LAST:event_jButton6ActionPerformed

    private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton5ActionPerformed

        // TODO add your handling code here:

        setNum("6");

    }//GEN-LAST:event_jButton5ActionPerformed

    private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton4ActionPerformed

        // TODO add your handling code here:

        setNum("5");

    }//GEN-LAST:event_jButton4ActionPerformed

    private void jButton3KeyTyped(java.awt.event.KeyEvent evt) {//GEN-FIRST:event_jButton3KeyTyped

        // TODO add your handling code here:

    }//GEN-LAST:event_jButton3KeyTyped

    private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton3ActionPerformed

        // TODO add your handling code here:

        setNum("4");

    }//GEN-LAST:event_jButton3ActionPerformed

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton2ActionPerformed

        // TODO add your handling code here:

        setNum("1");

    }//GEN-LAST:event_jButton2ActionPerformed

    private void jButton2MouseReleased(java.awt.event.MouseEvent evt) {//GEN-FIRST:event_jButton2MouseReleased

        // TODO add your handling code here:

    }//GEN-LAST:event_jButton2MouseReleased

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton1ActionPerformed

        // TODO add your handling code here:

        setNum("2");

    }//GEN-LAST:event_jButton1ActionPerformed

    private void jButton1MouseReleased(java.awt.event.MouseEvent evt) {//GEN-FIRST:event_jButton1MouseReleased

        // TODO add your handling code here:

    }//GEN-LAST:event_jButton1MouseReleased

    public void setNum(String str) {

        String strTest = new String(jTextField2.getText());

        if (strTest.equals("0")) {

            jTextField2.setText(str);

        } else {

            jTextField2.setText(strTest + str);

        }

    }

    public void setYSF(String strYSF) {

        //取出当前显示的内容放到字符串变量strTest中

        String strTest = jTextField2.getText();

//判断最右边一位是否是运算符

        int lastR = strTest.length() - 1;

        char ch = strTest.charAt(lastR);

//if是，将最右边一位运算符替换为当前运算符，并还给显示框

        if (ch == '+' || ch == '-' || ch == '*' || ch == '/') {

            String Result = strTest.substring(0, lastR);

            jTextField2.setText(Result + strYSF);

        } else {

            jTextField2.setText(strTest + strYSF);

        }

//else，直接添加该运算符，并还给显示框

    }

    /**

     * @param args the command line arguments

     */

    public static void main(String args[]) {

        /* Set the Nimbus look and feel */

        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">

        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.

         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
         */

        try {

            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {

                if ("Nimbus".equals(info.getName())) {

                    javax.swing.UIManager.setLookAndFeel(info.getClassName());

                    break;

                }

            }

        } catch (ClassNotFoundException ex) {

            java.util.logging.Logger.getLogger(CalculatorUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);

        } catch (InstantiationException ex) {

            java.util.logging.Logger.getLogger(CalculatorUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);

        } catch (IllegalAccessException ex) {

            java.util.logging.Logger.getLogger(CalculatorUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);

        } catch (javax.swing.UnsupportedLookAndFeelException ex) {

            java.util.logging.Logger.getLogger(CalculatorUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);

        }

        //</editor-fold>

        /* Create and display the form */

        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {

                new CalculatorUI().setVisible(true);

            }

        });

    }

    // Variables declaration - do not modify//GEN-BEGIN:variables

    private javax.swing.JButton jButton1;

    private javax.swing.JButton jButton10;

    private javax.swing.JButton jButton11;

    private javax.swing.JButton jButton12;

    private javax.swing.JButton jButton14;

    private javax.swing.JButton jButton15;

    private javax.swing.JButton jButton16;

    private javax.swing.JButton jButton17;

    private javax.swing.JButton jButton18;

    private javax.swing.JButton jButton19;

    private javax.swing.JButton jButton2;

    private javax.swing.JButton jButton3;

    private javax.swing.JButton jButton4;

    private javax.swing.JButton jButton5;

    private javax.swing.JButton jButton6;

    private javax.swing.JButton jButton7;

    private javax.swing.JButton jButton8;

    private javax.swing.JButton jButton9;

    private javax.swing.JLabel jLabel1;

    private javax.swing.JLayeredPane jLayeredPane1;

    private javax.swing.JPanel jPanel1;

    private javax.swing.JSeparator jSeparator1;

    private javax.swing.JTextField jTextField2;

    // End of variables declaration//GEN-END:variables

}