Java利用正则表达式实现中英文日期转换函数封装

超、凢脫俗 2023-10-09 18:57 29阅读 0赞

**前言：**

> Java利用正则表达式实现中英文日期互相转换函数封装，一共实现了6个方法（封装的原因是因为在Android中使用SimpleDateFormat 太麻烦了，各种try catch exception 特别麻烦，但是如果使用JDK8的LocalDate，则失去了对低版本OS的支持（jdk8最少要安卓8.0+才能支持）加上又不愿意使用第三方的日期包，so...）

以下是将 "yyyy-MM-dd" 转换为 "yyyy年M月d日" 或将 "yyyy-MM" 转换为 "yyyy年M月" 的示例代码已实现了相互转换，简单好用。

使用 `%d` 和 `%02d` 格式符将年份和月份格式化为不带前导零和带前导零的字符串。该代码首先使用正则表达式将输入的日期字符串匹配出年、月、日三个部分，然后将月份和日期字符串使用 `Integer.parseInt()` 方法转换为整数，最后使用 `%02d` 格式符将月份和日期格式化为两位数的字符串，自动补齐前导零。如果转为中文日期则去掉前导零。

//带前导零    
    public static String convertDateToChs(String dateStr) {
            String regex = "(\\d{4})-(\\d{1,2})-(\\d{1,2})";
            Pattern pattern = Pattern.compile(regex);
            Matcher matcher = pattern.matcher(dateStr);
            if (matcher.matches()) {
                String year = matcher.group(1);
                String month = matcher.group(2);
                String day = matcher.group(3);
                return String.format("%s年%s月%s日", year, month, day);
            } else {
                return dateStr;
            }
        }
    
    //不带前导零
        public static String convertToChinese(String dateStr) {
            String regex = "(\\d{4})-(\\d{1,2})-(\\d{1,2})";
            Pattern pattern = Pattern.compile(regex);
            Matcher matcher = pattern.matcher(dateStr);
            if (matcher.matches()) {
                int year = Integer.parseInt(matcher.group(1));
                int month = Integer.parseInt(matcher.group(2));
                int day = Integer.parseInt(matcher.group(3));
                return String.format("%d年%d月%d日", year, month, day);
            } else {
                return dateStr;
            }
        }
    
        public static String convertDateToEn(String dateStr) {
            String regex = "(\\d{4})年(\\d{1,2})月(\\d{1,2})日";
            Pattern pattern = Pattern.compile(regex);
            Matcher matcher = pattern.matcher(dateStr);
            if (matcher.matches()) {
                String year = matcher.group(1);
                String month = matcher.group(2);
                String day = matcher.group(3);
                return String.format("%s-%s-%s", year, month, day);
            } else {
                return dateStr;
            }
        }
    
        //使用 String.format() 方法的 %02d 格式符，将月份和日期格式化为两位数的字符串，自动补齐前导零
        public static String convertDateToEnglish(String dateStr) {
            String regex = "(\\d{4})年(\\d{1,2})月(\\d{1,2})日";
            Pattern pattern = Pattern.compile(regex);
            Matcher matcher = pattern.matcher(dateStr);
            if (matcher.matches()) {
                int year = Integer.parseInt(matcher.group(1));
                int month = Integer.parseInt(matcher.group(2));
                int day = Integer.parseInt(matcher.group(3));
                return String.format("%d-%02d-%02d", year, month, day);
            } else {
                return dateStr;
            }
        }
    
        public static String convertToShortChinese(String dateStr) {
            String regex = "(\\d{4})-(\\d{1,2})";
            Pattern pattern = Pattern.compile(regex);
            Matcher matcher = pattern.matcher(dateStr);
            if (matcher.matches()) {
                int year = Integer.parseInt(matcher.group(1));
                int month = Integer.parseInt(matcher.group(2));
                return String.format("%d年%d月", year, month);
            } else {
                return dateStr;
            }
        }
    
        public static String convertToShortEnglish(String dateStr) {
            String regex = "(\\d{4})年(\\d{1,2})月";
            Pattern pattern = Pattern.compile(regex);
            Matcher matcher = pattern.matcher(dateStr);
            if (matcher.matches()) {
                int year = Integer.parseInt(matcher.group(1));
                int month = Integer.parseInt(matcher.group(2));
                return String.format("%d-%02d", year, month);
            } else {
                return dateStr;
            }
        }

示例运行效果：

![ea436fc9c1914e84867d1f44df4b91fe.png][]

[ea436fc9c1914e84867d1f44df4b91fe.png]: https://img-blog.csdnimg.cn/ea436fc9c1914e84867d1f44df4b91fe.png