用Java设计和编写一个简易的计算器：实现计算器的界面；实现计算按钮不同的计算功能；显示计算器按钮运算后的结果。

好的，我可以为你提供一下思路：

1. 设计计算器界面：使用Java Swing库中的JFrame、JPanel、JButton等组件来构建一个简单的计算器界面。

2. 实现计算按钮不同的计算功能：定义一个Calculator类，其中包括加、减、乘、除等计算方法，并将其与计算器界面中的计算按钮进行关联。

3. 显示计算器按钮运算后的结果：在计算器界面中增加一个显示结果的文本框，并在每次进行计算后将计算结果显示在该文本框中。

下面是一个简化版的Java代码示例，帮助你更好地理解上述思路：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Calculator {
    JFrame frame;
    JPanel panel;
    JTextField result;
    JButton plus, minus, multiply, divide, clear, equals;
    double number1, number2, answer;
    String operator;

    public Calculator() {
        frame = new JFrame("Calculator");
        frame.setSize(400, 400);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        panel = new JPanel(new GridLayout(5, 1));

        result = new JTextField();
        result.setEditable(false);
        panel.add(result);

        plus = new JButton("+");
        plus.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                number1 = Double.parseDouble(result.getText());
                operator = "+";
                result.setText("");
            }
        });
        panel.add(plus);

        minus = new JButton("-");
        minus.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                number1 = Double.parseDouble(result.getText());
                operator = "-";
                result.setText("");
            }
        });
        panel.add(minus);

        multiply = new JButton("*");
        multiply.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                number1 = Double.parseDouble(result.getText());
                operator = "*";
                result.setText("");
            }
        });
        panel.add(multiply);

        divide = new JButton("/");
        divide.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                number1 = Double.parseDouble(result.getText());
                operator = "/";
                result.setText("");
            }
        });
        panel.add(divide);

        clear = new JButton("C");
        clear.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                result.setText("");
            }
        });
        panel.add(clear);

        equals = new JButton("=");
        equals.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                number2 = Double.parseDouble(result.getText());
                switch(operator) {
                    case "+":
                        answer = number1 + number2;
                        break;
                    case "-":
                        answer = number1 - number2;
                        break;
                    case "*":
                        answer = number1 * number2;
                        break;
                    case "/":
                        answer = number1 / number2;
                        break;
                }
                result.setText(String.valueOf(answer));
            }
        });
        panel.add(equals);

        frame.add(panel);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        Calculator calculator = new Calculator();
    }
}

希望对你有所帮助！