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import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;/*** @Author: zhangximing* @Email: 530659058@qq.com* @Date: 2023/10/10 11:41* @Description: 日期工具类*/
public class DateUtils {/*** 获取提前多少小时的日期时间* @param hour* @return*/public static String getBeforeByHourTime(int hour){String returnstr = "";Calendar calendar = Calendar.getInstance();calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY) - hour);SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm");returnstr = df.format(calendar.getTime());return returnstr;}/*** 提前多少天* @param days* @return*/public static String getBeforeDays(int days) {String returnstr = "";Calendar calendar = Calendar.getInstance();calendar.set(Calendar.DAY_OF_MONTH, calendar.get(Calendar.DAY_OF_MONTH) - days);SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");returnstr = df.format(calendar.getTime());return returnstr;}/*** 获取本月第一天* @return*/public static String getCurrentMonthFirstDay(){// 获取当前日期Calendar calendar = Calendar.getInstance();SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");// 将日期设置为第一天calendar.set(Calendar.DAY_OF_MONTH, 1);// 获取本月第一天的日期Date currentMonthFirstDay = calendar.getTime();return sdf.format(currentMonthFirstDay);}/*** 获取指定日期的上个月第一天日期* @param currentMonthFirstDay* @return*/public static String getLastMonthFirstDay(String currentMonthFirstDay){// 获取当前日期Calendar calendar = Calendar.getInstance();SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");Date date = null;try {date = sdf.parse(currentMonthFirstDay);} catch (ParseException e) {e.printStackTrace();}calendar.setTime(date);// 将日期设置为上个月calendar.add(Calendar.MONTH, -1);// 将日期设置为第一天calendar.set(Calendar.DAY_OF_MONTH, 1);// 获取上个月第一天的日期Date lastMonthFirstDay = calendar.getTime();return sdf.format(lastMonthFirstDay);}}