使用java swing完成简单的计算器

计算器可以完成简单的四则运算

实现效果如下：

首先是主界面：

import javax.swing.JFrame;public class MainView {public static void main(String[] args) {JFrame frame=new MyCalculator();frame.setVisible(true);}}

然后是实现：

import java.awt.BorderLayout;import java.awt.Button;import java.awt.Color;import java.awt.Component;import java.awt.Container;import java.awt.GridBagConstraints;import java.awt.GridBagLayout;import java.awt.GridLayout;import java.awt.Image;import java.awt.Insets;import java.awt.MenuItem;import java.awt.Toolkit;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.InputEvent;import java.awt.event.KeyEvent;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JMenu;import javax.swing.JMenuBar;import javax.swing.JMenuItem;import javax.swing.JOptionPane;import javax.swing.JPanel;import javax.swing.JScrollPane;import javax.swing.JTextArea;import javax.swing.JTextField;import javax.swing.KeyStroke;public class MyCalculator extends JFrame implements ActionListener{/** *  */private static final Insets insets = new Insets(0, 0, 0, 0);private static final long serialVersionUID = -5113379074442808199L;JMenu editMenu,helpMenu;JMenuItem copyMenuItem,pasteMenuItem,lookhelpMenuItem,aboutsMenuItem;JPanel panel;JPanel panel2;JButton buttonMC,buttonMR,buttonMS,buttonM1,buttonM2,buttonBS,buttonCE,buttonC;JButtonbuttonFC,buttongen,button7,button8,button9,buttonchu,buttonbai,button4;JButton button5,button6,buttoncheng,buttonx,button1,button2,button3,buttonjian;JButton button0,buttondian,buttonjia,buttondeng;JTextArea showText;JMenuBar menuBar;public MyCalculator() {initMenu();initFrame();}public void initMenu(){//设置菜单栏menuBar=new JMenuBar();//编辑菜单editMenu=new JMenu("编辑(E)");editMenu.setMnemonic('E');//菜单里的内容copyMenuItem=new JMenuItem("复制(C)");copyMenuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C,InputEvent.CTRL_MASK));copyMenuItem.setMnemonic('C');pasteMenuItem=new JMenuItem("粘贴(P)");pasteMenuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_V,InputEvent.CTRL_MASK));pasteMenuItem.setMnemonic('P');//向编辑菜单添加editMenu.add(copyMenuItem);editMenu.add(pasteMenuItem);//帮助菜单helpMenu=new JMenu("帮助(H)");helpMenu.setMnemonic('H');//菜单里的内容lookhelpMenuItem=new JMenuItem("查看帮助(V)");lookhelpMenuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_F1,0));lookhelpMenuItem.setMnemonic('V');aboutsMenuItem=new JMenuItem("关于计算器(A)");aboutsMenuItem.setMnemonic('A');//向帮助菜单添加helpMenu.add(lookhelpMenuItem);helpMenu.add(aboutsMenuItem);//向菜单栏添加编辑和帮助menuBar.add(editMenu);menuBar.add(helpMenu);this.setJMenuBar(menuBar); showText =new JTextArea();showText.setRows(2);showText.setText("");panel=new JPanel();panel2=new JPanel();panel.setLayout(new BorderLayout());//设置上方为文本panel.add(showText,BorderLayout.NORTH);panel.add(panel2);//嵌套布局panel2.setBackground(new Color(66, 166, 166));panel2.setLayout(new GridBagLayout());//第一行buttonMC=new JButton("MC");addComponent(panel2, buttonMC, 0, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonMR=new JButton("MR");addComponent(panel2, buttonMR, 1, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonMS=new JButton("MS");addComponent(panel2, buttonMS, 2, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonM1=new JButton("M+");addComponent(panel2, buttonM1, 3, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonM2=new JButton("M-");addComponent(panel2, buttonM2, 4, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);//第二行buttonBS=new JButton("←");addComponent(panel2, buttonBS, 0, 1, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonBS.addActionListener(this);buttonCE=new JButton("CE");addComponent(panel2, buttonCE, 1, 1, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonC=new JButton("C");addComponent(panel2, buttonC, 2, 1, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonC.addActionListener(this);buttonFC=new JButton("+-");addComponent(panel2, buttonFC, 3, 1, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttongen=new JButton("√");addComponent(panel2, buttongen, 4, 1, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);//第三行button7=new JButton("7");addComponent(panel2, button7, 0, 2, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button7.addActionListener(this);button8=new JButton("8");addComponent(panel2, button8, 1, 2, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button8.addActionListener(this);button9=new JButton("9");addComponent(panel2, button9, 2, 2, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button9.addActionListener(this);buttonchu=new JButton("/");addComponent(panel2, buttonchu, 3, 2, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonchu.addActionListener(this);buttonbai=new JButton("%");addComponent(panel2, buttonbai, 4, 2, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonbai.addActionListener(this);//第四行button4=new JButton("4");addComponent(panel2, button4, 0, 3, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button4.addActionListener(this);button5=new JButton("5");addComponent(panel2, button5, 1, 3, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button5.addActionListener(this);button6=new JButton("6");addComponent(panel2, button6, 2, 3, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button6.addActionListener(this);buttoncheng=new JButton("*");addComponent(panel2, buttoncheng, 3, 3, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttoncheng.addActionListener(this);buttonx=new JButton("1/x");addComponent(panel2, buttonx, 4, 3, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);//第五行button1=new JButton("1");addComponent(panel2, button1, 0, 4, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button1.addActionListener(this);button2=new JButton("2");addComponent(panel2, button2, 1, 4, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button2.addActionListener(this);button3=new JButton("3");addComponent(panel2, button3, 2, 4, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button3.addActionListener(this);buttonjian=new JButton("-");addComponent(panel2, buttonjian, 3, 4, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonjian.addActionListener(this);buttondeng=new JButton("=");addComponent(panel2, buttondeng, 4, 4, 1, 2, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttondeng.addActionListener(this);//第六行button0=new JButton("0");addComponent(panel2, button0, 0, 5, 2, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);button0.addActionListener(this);buttondian=new JButton(".");addComponent(panel2, buttondian, 2, 5, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonjia=new JButton("+");addComponent(panel2, buttonjia, 3, 5, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);buttonjia.addActionListener(this);this.add(panel);}public void initFrame(){//设置关闭窗体即关闭程序this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置窗体大小位置this.setSize(280, 320);this.setLocation(100, 100);//设置标题this.setTitle("呱？呱!");//设置图标Toolkit kit=Toolkit.getDefaultToolkit();Image img=kit.getImage("img/ico.jpg");this.setIconImage(img);this.setResizable(false);//设置可视（置于构造函数最后）}private static void addComponent(Container container, Component component, int gridx, int gridy,int gridwidth, int gridheight, int anchor, int fill) {//建立网格包对象GridBagConstraints gbc = new GridBagConstraints(gridx, gridy, gridwidth, gridheight, 1.0, 1.0,anchor, fill, insets, 0, 0);//添加到容器中container.add(component, gbc);}@Overridepublic void actionPerformed(ActionEvent e) {if (e.getSource()==button0) {int pos=showText.getCaretPosition();showText.insert("0", pos);}else if (e.getSource()==button1) {int pos=showText.getCaretPosition();showText.insert("1", pos);}else if (e.getSource()==button2) {int pos=showText.getCaretPosition();showText.insert("2", pos);}else if (e.getSource()==button3) {int pos=showText.getCaretPosition();showText.insert("3", pos);}else if (e.getSource()==button4) {int pos=showText.getCaretPosition();showText.insert("4", pos);}else if (e.getSource()==button5) {int pos=showText.getCaretPosition();showText.insert("5", pos);}else if (e.getSource()==button6) {int pos=showText.getCaretPosition();showText.insert("6", pos);}else if (e.getSource()==button7) {int pos=showText.getCaretPosition();showText.insert("7", pos);}else if (e.getSource()==button8) {int pos=showText.getCaretPosition();showText.insert("8", pos);}else if (e.getSource()==button9) {int pos=showText.getCaretPosition();showText.insert("9", pos);}else if (e.getSource()==buttonjia) {int pos=showText.getCaretPosition();showText.insert("+", pos);}else if (e.getSource()==buttonjian) {int pos=showText.getCaretPosition();showText.insert("-", pos);}else if (e.getSource()==buttoncheng) {int pos=showText.getCaretPosition();showText.insert("*", pos);}else if (e.getSource()==buttonchu) {int pos=showText.getCaretPosition();showText.insert("/", pos);}else if (e.getSource()==buttonBS) {int pos=showText.getCaretPosition();if( !( showText.getText().equals("")) ) {                StringBuffer sb = new StringBuffer();                  sb.append(showText.getText());                sb.delete(pos-1 , pos);                  showText.setText(sb.toString());            }}else if (e.getSource()==buttondeng) {int pos=showText.getCaretPosition();String cmd = showText.getText();              Calculate cl = new Calculate();                            String resultMsg = cl.calResult(cmd);              if ( resultMsg.equals("算式格式错误") || resultMsg.equals("除数不能为0") ) {                  JOptionPane.showMessageDialog(null, resultMsg, "错误", JOptionPane.WARNING_MESSAGE);              }              else {              showText.insert("="+resultMsg, pos);             } }else if (e.getSource()==buttonC) {showText.setText("");}}}

最后是计算的工具类：

import java.util.Stack;  import java.util.regex.Matcher;  import java.util.regex.Pattern;import javax.swing.JFrame;    //import sun.security.krb5.internal.ccache.CCacheInputStream;    public class Calculate {     private Stack<Double> numStack = new Stack<Double>();      private Stack<Character> sybStack = new Stack<Character>();             public String calResult ( String equation ) {                    //替换乘除号          equation = equation.replace("X", "*");          equation = equation.replace("÷", "/");                    //处理负号          equation = negativeNumTransfer(equation);                    if ( !checkFormat(equation) ) {              return "算式格式错误";          }                    equation += "#";          StringBuffer tempNum = new StringBuffer();          StringBuffer exp = new StringBuffer().append(equation);                    while ( exp.length() != 0 ) {                            String temp = exp.substring(0,1);              exp.delete(0, 1);                            if( isNum(temp) )  { // temp是数字                  tempNum.append(temp);              }              else { // temp不是数字                                    if (!"".equals(tempNum.toString())) {                      // 当表达式的第一个符号为括号                      double num = Double.parseDouble(tempNum.toString());                      numStack.push(num);                      tempNum.delete(0, tempNum.length());                  }                  // 用当前取得的运算符与栈顶运算符比较优先级：若高于，则因为会先运算，放入栈顶；若等于，因为出现在后面，                  // 所以会后计算，所以栈顶元素出栈，取出操作数运算；若小于，则同理，取出栈顶元素运算，将结果入操作数栈。                    // 判断当前运算符与栈顶元素优先级，取出元素，进行计算(因为优先级可能小于栈顶元素，还小于第二个元素等等，需要用循环判断)                  while ( !compare(temp.charAt(0)) && (!sybStack.empty()) ) {                      double a = numStack.pop();                      double b = numStack.pop();                      char ope = sybStack.pop();                                            // 进行简单的计算                      if( simpleCal(ope, a, b) == false ) {                          return "除数不能为0";                      }                                        }                                    // 判断当前运算符与栈顶元素优先级， 如果高，或者低于平，计算完后，将当前操作符号，放入操作符栈                  refreshSybStack(temp);                                }                        }                    return getResultStr(numStack.pop());      }            private void refreshSybStack ( String temp) {          if (temp.charAt(0) != '#') {              sybStack.push(new Character(temp.charAt(0)));              if (temp.charAt(0) == ')') {// 当栈顶为'('，而当前元素为')'时，则是括号内以算完，去掉括号                  sybStack.pop();                  sybStack.pop();              }          }      }             private boolean simpleCal ( char ope, double a, double b ) {                    double result = 0;                    switch (ope) {          case '+':              result = b + a;              numStack.push(result);              break;          case '-':              result = b - a;              numStack.push(result);              break;          case '*':              result = b * a;              numStack.push(result);              break;          case '/':                            if ( a == 0.0 ) {                  return false;              }              else {                  result = b / a;                  numStack.push(result);                  break;              }                        }                    return true;      }            private String negativeNumTransfer( String equation ) {          // 处理算式，将表示负数的部分进行改动，转成calResult方法支持的                     if( equation.length() <= 1 ) {              return equation;          }                    StringBuffer str = new StringBuffer().append(equation);                    for ( int i = 0; i < str.length()-1; ++i ) {                            if( !str.substring(i, i+1).equals("-") ) {                  continue;              }                            if ( i == 0 ) {                  char temp = str.charAt(1);                  if( isNumChar(temp) || isDecimalPoint(temp) || isLeftBracket(temp) ) {                      str.insert(0, "0");                      i++;                  }              }              else {                  char last = str.charAt(i-1);                  char next = str.charAt(i+1);                                    if( isLeftBracket(last) &&                      ( isNumChar(next) || isDecimalPoint(next) || isLeftBracket(next) ) ) {                      str.insert(i, "0");                      i++;                  }              }          }                                      return str.toString();      }                        private boolean checkFormat ( String equation ) {          char[] c = equation.toCharArray();          int singleBracket = 0;                    for( int i = 0; i < c.length; ++i ) {                            if( isLeftBracket(c[i]) ) {                  singleBracket++;              }              if ( isRightBracket(c[i]) ) {                  singleBracket--;              }                            if ( i == 0 ) { //第1个元素只能是[0-9]或者是左括号                  if( !isLeftBracket(c[i]) && !isNumChar(c[i]) ) {                      return false;                  }              }              else if ( isNumChar(c[i]) || isDecimalPoint(c[i]) ) { //数字左边不能是右括号                  if ( isRightBracket(c[i-1]) ) {                      return false;                  }              }              else if( isLeftBracket(c[i]) )  { // 左括号的左边不能是数字和右括号                  if ( isNumChar(c[i-1]) || isDecimalPoint(c[i-1]) || isRightBracket(c[i-1]) ) {                      return false;                  }              }              else {  // 右括号和四则运算符的左边只能是数字或者右括号                  if ( !isNumChar(c[i-1]) && !isRightBracket(c[i-1]) ) {                      return false;                  }              }                        }                    return singleBracket == 0;      }        private static boolean isNum ( String temp ) {          return temp.matches("[0-9]") || temp.equals(".");      }            private static boolean isLeftBracket ( char c ) {          return c == '(';      }            private static boolean isRightBracket ( char c ) {          return c == ')';      }            private static boolean isDecimalPoint ( char c ) {          return c == '.';      }            private static boolean isNumChar ( char c ) {          return ( c >= '0' && c <= '9' );      }        private boolean compare (char str) {          if ( sybStack.empty() ) {              // 当为空时，显然 当前优先级最低，返回高              return true;          }          char last = (char) sybStack.lastElement();          // 如果栈顶为'('显然，优先级最低，')'不可能为栈顶。          if (last == '(') {              return true;          }          switch (str) {          case '#':              return false;// 结束符          case '(':              // '('优先级最高,显然返回true              return true;          case ')':              // ')'优先级最低，              return false;          case '*': {              // '*/'优先级只比'+-'高              if (last == '+' || last == '-')                  return true;              else                  return false;          }          case '/': {              if (last == '+' || last == '-')                  return true;              else                  return false;          }          // '+-'为最低，一直返回false          case '+':              return false;          case '-':              return false;          }          return true;      }            private String getResultStr ( double result ) {          StringBuffer s = new StringBuffer().append( result + "" );                    if ( s.substring(s.length() - 2).equals(".0") ) {              s.delete( s.length()-2 , s.length() );          }                    return s.toString();      }        }