转换成代码如下：

为了操作方便，也避免计算出错，这里将各个时间单位转换为秒数定义为静态常量，并且使用DateTimFormatter格式化保证多线程安全，如下：

封装DateUtil工具类

import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.Date;
 * @Author: lzp
 * @description:
 * @Date: 2022/8/6
public class DateUtils {
     * 一天、一分钟、一小时对应的秒数
    private static final Long ONE_MINUTE_TO_SECOND = 60L;
    private static final Long ONE_HOUR_TO_SECOND = ONE_MINUTE_TO_SECOND * 60;
    private static final Long ONE_DAY_TO_SECOND = ONE_HOUR_TO_SECOND * 24;
     * 使用LocalDateTime进行格式化 保证多线程安全
    private static final DateTimeFormatter DATE_TIME_FORMATTER1 = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    private static final DateTimeFormatter DATE_TIME_FORMATTER2 = DateTimeFormatter.ofPattern("MM-dd");
     * 设置推送消息的时间描述
     * 1. 1分钟内：刚刚
     * 2. 60分钟内：x分钟前
     * 3. 24小时内：x小时前
     * 4. >24小时：x月x日  08-1
     * 5. 非年内：年-月-日 2021-05-02
     * @param now        当前时间  传一个当前时间目的是方便遍历，减少date对象的创建
     * @param targetDate 与当前时间做对比的时间
    public static String getTimeDescriptionByDate(Date now, Date targetDate) {
        String timeDescription = "";
        if (targetDate != null) {
            // 5. 年内判断
            if (targetDate.getYear() == now.getYear()) {
                // 获取秒数差
                long betweenSeconds = (now.getTime() - targetDate.getTime()) / 1000;
                if (betweenSeconds < ONE_MINUTE_TO_SECOND) {
                    // 1. 1分钟内：刚刚
                    timeDescription = "刚刚";
                } else if (betweenSeconds < ONE_HOUR_TO_SECOND) {
                    // 2. 60分钟内
                    timeDescription = betweenSeconds / ONE_MINUTE_TO_SECOND + "分钟前";
                } else if (betweenSeconds < ONE_HOUR_TO_SECOND * 24) {
                    // 3. 24小时内：x小时前
                    timeDescription = betweenSeconds / ONE_HOUR_TO_SECOND + "小时前";
                } else {
                    // 4. >24小时：x月x日  08-1
                    timeDescription = dateToLocalDateTime(targetDate).format(DATE_TIME_FORMATTER2);
            } else {
                timeDescription = dateToLocalDateTime(targetDate).format(DATE_TIME_FORMATTER1);
        return timeDescription;
     * date转localDateTime
    public static LocalDateTime dateToLocalDateTime(Date date) {
        return date.toInstant().atZone(ZoneId.systemDefault()).toLocalDateTime();
测试类，直接运行即可，能够自动按照当前时间显示对应的描述：
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
 * @Author: lzp
 * @description:
 * @Date: 2022/8/6
public class Demo {
    public static void main(String[] args) throws ParseException {
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date now = new Date();
        Calendar cal = Calendar.getInstance();
        cal.setTime(now);
        System.out.printf("当前时间为：%s ==============================\n", df.format(now));
        cal.add(Calendar.SECOND, -20); // 20秒前
        System.out.printf("%s => %s\n", df.format(cal.getTime()), DateUtils.getTimeDescriptionByDate(now, cal.getTime()));
        cal.add(Calendar.MINUTE, -1); // 1分钟前
        System.out.printf("%s => %s\n", df.format(cal.getTime()), DateUtils.getTimeDescriptionByDate(now, cal.getTime()));
        cal.add(Calendar.HOUR, -1); // 1小时前
        System.out.printf("%s => %s\n", df.format(cal.getTime()), DateUtils.getTimeDescriptionByDate(now, cal.getTime()));
        cal.add(Calendar.DAY_OF_MONTH, -1); // 1天前
        System.out.printf("%s => %s\n", df.format(cal.getTime()), DateUtils.getTimeDescriptionByDate(now, cal.getTime()));
        cal.add(Calendar.YEAR, -1); // 1年前
        System.out.printf("%s => %s\n", df.format(cal.getTime()), DateUtils.getTimeDescriptionByDate(now, cal.getTime()));
        java开发
       
粉丝
 
  
   
    
友情链接：