需要安装好的插件

在设置代码保存时候自动实现格式化功能前需要安装好两个插件，分别是：

• google-java-format
• Save Action
  具体的安装过程，我在上一篇文章介绍过了。

google-java-format设置

google-java-format设置前，需要打开下面途中的其他设置，双击 google-java-format插件，在右侧选项中勾选Enable google-java-format选项。

Save Action设置

Save Action设置需要勾选相关的选项，实现保存时候自动格式化代码。

效果

当所有配置好了之后，按住Ctrl+S则可以在保存的同时格式化代码格式。
以下为格式化后的一段计算器代码，非常快捷高效。

package Calculator;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Stack;
import javax.swing.*;

class MyException extends Exception {
    public MyException() {
        super();
    }

    public MyException(String message) {
        super(message);
    }
}

class SwingConsole {
    public static void run(final JFrame f, final int width, final int height) {//酱紫，里面可以用非main方法
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                f.setTitle(f.getClass().getSimpleName());
                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                f.setSize(width, height);
                f.setVisible(true);
            }
        });
    }
}

public class Calculator extends JFrame {//这是我的public类,ONLY ONE


    private JTextField textField;                //输入文本框
    private String input;                        //结果
    private String operator;                    //操作符

    public Calculator() { //函数
        input = "";
        operator = "";

        Container container = this.getContentPane();
        JPanel panel = new JPanel();
        textField = new JTextField(30);
        textField.setEditable(false);                        //文本框禁止编辑
        textField.setHorizontalAlignment(JTextField.LEFT);
        //textField.setBounds(100, 100, 20, 20);            //在容器布局为空情况下生效
        textField.setPreferredSize(new Dimension(200, 30));
        container.add(textField, BorderLayout.NORTH);

        String[] name = {"7", "8", "9", "+", "4", "5", "6", "-", "1", "2", "3", "*", "0", "C", "=", "/"};

        panel.setLayout(new GridLayout(4, 4, 1, 1));

        for (int i = 0; i < name.length; i++) {
            JButton button = new JButton(name[i]);
            button.addActionListener(new MyActionListener());
            panel.add(button);
        }
        container.add(panel, BorderLayout.CENTER);
    }

    class MyActionListener implements ActionListener {            //内部类实现按钮响应

        @Override
        public void actionPerformed(ActionEvent e) {
            int cnt = 0;
            String actionCommand = e.getActionCommand();            //获取按钮上的字符串
            if (actionCommand.equals("+") || actionCommand.equals("-") || actionCommand.equals("*")
                    || actionCommand.equals("/")) {
                input += " " + actionCommand + " ";
            } else if (actionCommand.equals("C")) {                    //清除输入
                input = "";
            } else if (actionCommand.equals("=")) {                    //按下等号
                try {
                    input += "=" + calculate(input);
                } catch (MyException e1) {
                    if (e1.getMessage().equals("Infinity"))
                        input += "=" + e1.getMessage();
                    else
                        input = e1.getMessage();
                }
                textField.setText(input);
                input = "";
                cnt = 1;
            } else
                input += actionCommand;                            //按下数字

            if (cnt == 0)
                textField.setText(input);
        }
    }

    private String calculate(String input) throws MyException {                //计算函数
        String[] comput = input.split(" ");
        Stack<Double> stack = new Stack<>();
        Double m = Double.parseDouble(comput[0]);
        stack.push(m);                                        //第一个操作数入栈

        for (int i = 1; i < comput.length; i++) {
            if (i % 2 == 1) {
                if (comput[i].equals("+"))
                    stack.push(Double.parseDouble(comput[i + 1]));
                if (comput[i].equals("-"))
                    stack.push(-Double.parseDouble(comput[i + 1]));
                if (comput[i].equals("*")) {                    //将前一个数出栈做乘法再入栈
                    Double d = stack.peek();                //取栈顶元素
                    stack.pop();
                    stack.push(d * Double.parseDouble(comput[i + 1]));
                }
                if (comput[i].equals("/")) {                    //将前一个数出栈做乘法再入栈
                    double help = Double.parseDouble(comput[i + 1]);
                    if (help == 0)
                        throw new MyException("Infinity");            //不会继续执行该函数
                    double d = stack.peek();
                    stack.pop();
                    stack.push(d / help);
                }
            }
        }

        double d = 0d;

        while (!stack.isEmpty()) {            //求和
            d += stack.peek();
            stack.pop();
        }

        String result = String.valueOf(d);
        return result;
    }

    public static void main(String[] args) {
        SwingConsole.run(new Calculator(), 250, 300);
    }
}