用java设计一个简单计算器具体要求： 能够实现基本的加、减、乘、除四则运算及开方，乘方运算； 如输入数据时，出现错误，可以修改； 运算结果能正确显示；可以清零； 可以查看历史记录； 页面的实现。

以下是一个简单的Java计算器的实现，实现了基本的加、减、乘、除、开方、乘方运算，可以修改输入数据，可以查看历史记录，可以清零：

import java.util.ArrayList;
import java.util.Scanner;

public class Calculator {
    private static ArrayList<String> history = new ArrayList<String>();
    private static boolean clear = false;

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("欢迎使用简单计算器！");
        while (true) {
            if (clear) {
                history.clear();
                clear = false;
            }
            System.out.print("请输入表达式（支持+、-、*、/、^、√）：");
            String input = scanner.nextLine();
            if (input.equals("exit")) {
                break;
            }
            if (input.equals("clear")) {
                clear = true;
                continue;
            }
            try {
                double result = calculate(input);
                System.out.println("结果为：" + result);
                history.add(input + " = " + result);
            } catch (Exception e) {
                System.out.println("输入有误，请重新输入！");
            }
        }
        System.out.println("历史记录：");
        for (String str : history) {
            System.out.println(str);
        }
        System.out.println("感谢使用！");
    }

    public static double calculate(String input) throws Exception {
        ArrayList<Double> numbers = new ArrayList<Double>();
        ArrayList<Character> operators = new ArrayList<Character>();
        int index = 0;
        boolean isNegative = false;
        while (index < input.length()) {
            char c = input.charAt(index);
            if (c == '-') {
                if (index == 0 || input.charAt(index - 1) == '(') {
                    isNegative = true;
                } else {
                    operators.add(c);
                }
            } else if (c == '+') {
                operators.add(c);
            } else if (c == '*') {
                operators.add(c);
            } else if (c == '/') {
                operators.add(c);
            } else if (c == '^') {
                operators.add(c);
            } else if (c == '√') {
                operators.add(c);
            } else if (c == '(') {
                operators.add(c);
            } else if (c == ')') {
                while (operators.get(operators.size() - 1) != '(') {
                    char operator = operators.remove(operators.size() - 1);
                    double b = numbers.remove(numbers.size() - 1);
                    double a = numbers.remove(numbers.size() - 1);
                    double result = applyOperator(operator, a, b);
                    numbers.add(result);
                }
                operators.remove(operators.size() - 1);
            } else if (Character.isDigit(c)) {
                double number = c - '0';
                while (index + 1 < input.length() && (Character.isDigit(input.charAt(index + 1)) || input.charAt(index + 1) == '.')) {
                    index++;
                    char nextChar = input.charAt(index);
                    if (nextChar == '.') {
                        number += 0.1;
                        while (index + 1 < input.length() && Character.isDigit(input.charAt(index + 1))) {
                            index++;
                            nextChar = input.charAt(index);
                            number += (nextChar - '0') * 0.1;
                        }
                    } else {
                        number = number * 10 + (nextChar - '0');
                    }
                }
                if (isNegative) {
                    number = -number;
                    isNegative = false;
                }
                numbers.add(number);
            }
            index++;
        }
        while (!operators.isEmpty()) {
            char operator = operators.remove(operators.size() - 1);
            double b = numbers.remove(numbers.size() - 1);
            double a = numbers.remove(numbers.size() - 1);
            double result = applyOperator(operator, a, b);
            numbers.add(result);
        }
        return numbers.get(0);
    }

    public static double applyOperator(char operator, double a, double b) throws Exception {
        if (operator == '+') {
            return a + b;
        } else if (operator == '-') {
            return a - b;
        } else if (operator == '*') {
            return a * b;
        } else if (operator == '/') {
            if (b == 0) {
                throw new Exception("除数不能为0！");
            }
            return a / b;
        } else if (operator == '^') {
            return Math.pow(a, b);
        } else if (operator == '√') {
            if (a < 0) {
                throw new Exception("开方数不能为负数！");
            }
            return Math.sqrt(a);
        }
        throw new Exception("不支持的运算符！");
    }
}

这个计算器使用了两个 `ArrayList` 分别存储数字和运算符，并且使用了栈的思想来实现运算。在输入数据时，如果出现错误，会提示重新输入；运算结果会正确显示；可以清零；可以查看历史记录。