org.junit.Test 
org.junit.Before
org.junit.After
org.junit.BeforeClass
org.junit.AfterClass
org.junit.Ignore
org.junit.runner.RunWith
org.junit.runners.Suite.SuiteClasses
org.junit.runners.Parameterized.Parameters

package io.shentuzhigang.demo.blackbox;

import java.util.regex.Pattern;

/**
 * @author ShenTuZhiGang
 * @version 1.0.0
 * @date 2021-05-06 15:43
 */
public class Date {
    private static final Pattern pattern = Pattern.compile("^[-\\+]?[\\d]*$");

    public static String nextDate(String s_year, String s_month, String s_day) {
        //檢測是否存在無效字符
        if (!(isInteger(s_year) && isInteger(s_month) && isInteger(s_day))) {
            return "無效的輸入日期！";
        }
        //將字符串轉為int
        int year = Integer.parseInt(s_year);
        int month = Integer.parseInt(s_month);
        int day = Integer.parseInt((s_day));
        boolean flag = false;
        if (year < 1900 || year > 2050) {
            return ("年的值不在指定范圍之內");
        } else if (month > 12 || month < 1) {
            return ("月的值不在指定范圍之內");
        } else if (day > 31 || day < 1) {
            return ("日的值不在指定范圍之內");
        }

        switch (month) {
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
                if (day == 31) {
                    day = 1;
                    month = month + 1;
                } else {
                    day = day + 1;
                }
                break;
            case 4:
            case 6:
            case 9:
            case 11:
                if (day == 30) {
                    day = 1;
                    month = month + 1;
                } else if (day == 31) {
                    flag = true;
                } else {
                    day = day + 1;
                }
                break;
            case 12:
                if (day == 31) {
                    day = 1;
                    month = 1;
                    year = year + 1;
                } else {
                    day = day + 1;
                }
                break;
            case 2: {
                if (((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)) {
                    // 閏年
                    if (day == 29) {
                        day = 1;
                        month = 3;
                    } else if (day < 29) {
                        day = day + 1;
                    } else {
                        flag = true;
                        // day超過29
                    }
                } else {
                    //非閏年
                    if (day == 28) {
                        day = 1;
                        month = 3;
                    } else if (day < 28) {
                        day = day + 1;
                    } else {
                        flag = true;
                    }
                }

            }
            break;
            default:
        }

        if (year > 2050) {
            return ("年的值不在指定范圍之內");
        } else if (flag) {
            return ("日的值不在指定范圍之內");
        } else {
            return ("下一天是" + year + "年" + month + "月" + day + "日！");
        }
    }

    /**
     * 判斷輸入字符串是否是整數(shù)型
     *
     * @param str
     * @return
     */
    public static boolean isInteger(String str) {
        return pattern.matcher(str).matches();
    }
}

package io.shentuzhigang.demo.blackbox;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;

import java.util.Arrays;
import java.util.Collection;

/**
 * @author ShenTuZhiGang
 * @version 1.0.0
 * @date 2021-05-06 15:43
 */
@RunWith(Parameterized.class)
public class DateTests {
    private String input1;
    private String input2;
    private String input3;
    private String expected;

    @Parameters
    public static Collection<?> prepareData(){
        String [][] object = {
                // 有效等價類
                {"2016","2","29","下一天是2016年3月1日！"},
                {"2017","1","28","下一天是2017年1月29日！"},
                {"2017","1","31","下一天是2017年2月1日！"},
                {"2017","4","30","下一天是2017年5月1日！"},
                // 無效等價類
                {"1899","3","1","年的值不在指定范圍之內"},
                {"2051","3","1","年的值不在指定范圍之內"},
                {"205%","3","1","無效的輸入日期！"},
                {"1901","-1","1","月的值不在指定范圍之內"},
                {"1901","13","1","月的值不在指定范圍之內"},
                {"1901","1%","1","無效的輸入日期！"},
                {"1901","1","-1","日的值不在指定范圍之內"},
                {"2016","2","30","日的值不在指定范圍之內"},
                {"2017","2","29","日的值不在指定范圍之內"},
                {"2017","3","32","日的值不在指定范圍之內"},
                {"2017","4","31","日的值不在指定范圍之內"},
                {"2017","4","32","日的值不在指定范圍之內"},
                {"2017","4","3%","無效的輸入日期！"}
        };
        return Arrays.asList(object);
    }
    public DateTests(String input1,String input2,String input3,String expected){
        this.input1 = input1;
        this.input2 = input2;
        this.input3 = input3;
        this.expected = expected;

    }
    @Test
    public void testDate(){
        String result = Date.nextDate(input1,input2,input3);
        Assert.assertEquals(expected,result);
    }
}