本文实例讲述了java实现的日期时间转换工具类。分享给大家供大家参考，具体如下：

最基础的东西，总结一下，下次用的时候就方便一些了。废话不多说，直接贴代码：

package com.incar.base.util;
import com.incar.base.exception.BaseRuntimeException;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.time.*;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;
import java.time.temporal.WeekFields;
import java.util.*;
/**
 * Created by Administrator on 2017/4/11.
 */
public class DateUtil {
 public final static String DATE_FORMAT_DAY = "yyyy-MM-dd";
 public final static String DATE_FORMAT_SECOND = "yyyy-MM-dd HH:mm:ss";
 private final static int[] DATE_UNIT_ARR = new int[]{Calendar.MILLISECOND, Calendar.SECOND, Calendar.MINUTE, Calendar.HOUR_OF_DAY,
   Calendar.DATE, Calendar.MONTH, Calendar.YEAR};
 public static Calendar calendar = null;
 public static DateFormat dateFormat = null;
 public static Date date = null;
 /**
  * 将日期转为 字符串
  * @param date
  * @param format
  * @return
  */
 public static String dateToString(Date date, String format) {
  if (date == null) {
   return null;
  }
  return new SimpleDateFormat(format).format(date);
 }
 /**
  * 将日期转换为 字符串(转换的时间按照当前登录用户的时区)
  *
  * @param date
  * @param format
  * @param timeZone
  * @return
  */
 public static String dateToString(Date date, String format, String timeZone) {
  if (date == null) {
   return null;
  }
  //1、格式化日期
  return getTimeZoneSimpleDateFormat(format, timeZone).format(date);
 }
 /**
  * 获取当前登录用户的 日期格式化对象
  *
  * @param timeZone
  * @param format
  * @return
  */
 private static SimpleDateFormat getTimeZoneSimpleDateFormat(String format, String timeZone) {
  //1、获取对应时区的格式化器
  SimpleDateFormat simpleDateFormat = new SimpleDateFormat(format);
  simpleDateFormat.setTimeZone(TimeZone.getTimeZone(timeZone));
  return simpleDateFormat;
 }
 /**
  *将字符串转为日期（转换的时间按照当前登录用户的时区）
  * @param dateStr
  * @param format
  * @return
  */
 public static Date stringToDate(String dateStr, String format, String timeZone) {
  if (dateStr == null || format == null) {
   return null;
  }
  try {
   return getTimeZoneSimpleDateFormat(format, timeZone).parse(dateStr);
  } catch (ParseException e) {
   throw BaseRuntimeException.getException(e);
  }
 }
 /**
  *将字符串转为日期
  * @param dateStr
  * @param format
  * @return
  */
 public static Date stringToDate_CTT(String dateStr, String format) {
  if (dateStr == null || format == null) {
   return null;
  }
  try {
   return getTimeZoneSimpleDateFormat(format, "CTT").parse(dateStr);
  } catch (ParseException e) {
   throw BaseRuntimeException.getException(e);
  }
 }
 /**
  * 获取最近在当前日期之前的最后一个日期单位
  *
  * @param date
  * @param calendarUnit 只支持 DateUtil.DATE_UNIT_ARR
  * @return
  */
 public static Date getFloorDate(Date date, int calendarUnit) {
  if (date == null) {
   return null;
  }
  Calendar calendar = Calendar.getInstance();
  calendar.setTime(date);
  for (int i = 0; i <= DATE_UNIT_ARR.length - 1; i++) {
   if (DATE_UNIT_ARR[i] > calendarUnit) {
    if (Calendar.DATE == DATE_UNIT_ARR[i]) {
     calendar.set(DATE_UNIT_ARR[i], 1);
    } else {
     calendar.set(DATE_UNIT_ARR[i], 0);
    }
   }
   if (DATE_UNIT_ARR[i] == calendarUnit) {
    break;
   }
  }
  return calendar.getTime();
 }
 /**
  * 获取最近在当前日期之后的第一个日期单位
  *
  * @param date
  * @param calendarUnit 只支持 DateUtil.DATE_UNIT_ARR
  * @return
  */
 public static Date getCeilDate(Date date, int calendarUnit) {
  if (date == null) {
   return null;
  }
  Calendar calendar = Calendar.getInstance();
  calendar.setTime(date);
  for (int i = 0; i <= DATE_UNIT_ARR.length - 1; i++) {
   if (DATE_UNIT_ARR[i] > calendarUnit) {
    if (Calendar.DATE == DATE_UNIT_ARR[i]) {
     calendar.set(DATE_UNIT_ARR[i], 1);
    } else {
     calendar.set(DATE_UNIT_ARR[i], 0);
    }
   }
   if (DATE_UNIT_ARR[i] == calendarUnit) {
    calendar.add(DATE_UNIT_ARR[i], 1);
    break;
   }
  }
  return calendar.getTime();
 }
 /**
  * 将开始时间、结束时间 根据日期单位划分成 时间段
  *
  *
  * @param startDate
  * @param endDate
  * @param calendarUnit Calendar.MONTH,Calendar.DATE
  * @param dateNum  指定的单位日期数量
  * @return 每一个数组第一个为开始时间,第二个为结束时间; 第一个元素结束时间总是等于第二元素开始时间
  */
 public static List<Date[]> splitDate(Date startDate, Date endDate, int calendarUnit, int dateNum) {
  List<Date[]> returnList = new ArrayList<>();
  if (startDate.getTime() > endDate.getTime()) {
   return null;
  }
  Calendar c1 = Calendar.getInstance();
  Calendar c2 = Calendar.getInstance();
  c1.setTime(startDate);
  c2.setTime(endDate);
  Calendar curC1 = Calendar.getInstance();
  Calendar curC2 = null;
  curC1.setTime(startDate);
  while (curC2 == null || curC2.before(c2)) {
   if (curC2 == null) {
    curC2 = Calendar.getInstance();
    curC2.setTime(startDate);
    curC2.add(calendarUnit, dateNum);
   } else {
    curC1.add(calendarUnit, dateNum);
    curC2.add(calendarUnit, dateNum);
   }
   returnList.add(new Date[]{curC1.getTime(), curC2.getTime()});
  }
  //设置最后一个区间的截至日期为endDate
  returnList.get(returnList.size() - 1)[1] = endDate;
  return returnList;
 }
 /**
  * 获取开始时间结束时间按照 日期单位 形成多个日期区间
  * 分割出来的时间区间以
  * 第一个区间开始时间为传入开始时间
  * 最后一个区间结束时间为传入结束时间
  * @param startDate
  * @param endDate
  * @param unit 1:代表按日;2:代表按周;3:代表按月
  * @return
  */
 public static List<Date[]> rangeDate(Date startDate, Date endDate, int unit){
  List<Date[]> returnList=new ArrayList<>();
  LocalDateTime ldt1= LocalDateTime.ofInstant(startDate.toInstant(),ZoneId.of("+8"));
  LocalDateTime ldt2= LocalDateTime.ofInstant(endDate.toInstant(),ZoneId.of("+8"));
  switch (unit){
   case 1:{
    LocalDateTime start= ldt1.with(ChronoField.SECOND_OF_DAY,0);
    LocalDateTime end= ldt1.with(ChronoField.SECOND_OF_DAY, ChronoUnit.DAYS.getDuration().getSeconds()-1);
    while(true){
     returnList.add(new Date[]{Date.from(start.toInstant(ZoneOffset.of("+8"))),Date.from(end.toInstant(ZoneOffset.of("+8")))});
     if(!ldt2.isBefore(start)&&!ldt2.isAfter(end)){
      break;
     }else{
      start=start.plusDays(1);
      end=end.plusDays(1);
     }
    }
    break;
   }
   case 2:{
    int dayOfWeek=ldt1.get(ChronoField.DAY_OF_WEEK);
    LocalDateTime start= ldt1.plusDays(1-dayOfWeek).with(ChronoField.SECOND_OF_DAY,0);
    LocalDateTime end= ldt1.plusDays(7-dayOfWeek).with(ChronoField.SECOND_OF_DAY, ChronoUnit.DAYS.getDuration().getSeconds()-1);
    while(true){
     returnList.add(new Date[]{Date.from(start.toInstant(ZoneOffset.of("+8"))),Date.from(end.toInstant(ZoneOffset.of("+8")))});
     if(!ldt2.isBefore(start)&&!ldt2.isAfter(end)){
      break;
     }else{
      start=start.plusWeeks(1);
      end=end.plusWeeks(1);
     }
    }
    if(returnList.size()>0){
     Date[] firstEle=returnList.get(0);
     Date[] lastEle=returnList.get(returnList.size()-1);
     firstEle[0]=Date.from(ldt1.with(ChronoField.SECOND_OF_DAY,0).toInstant(ZoneOffset.of("+8")));
     lastEle[1]=Date.from(ldt2.with(ChronoField.SECOND_OF_DAY,0).toInstant(ZoneOffset.of("+8")));
    }
    break;
   }
   case 3:{
    LocalDateTime temp=ldt1;
    while(true) {
     int dayOfMonth = temp.get(ChronoField.DAY_OF_MONTH);
     int max = temp.getMonth().maxLength();
     LocalDateTime start = temp.plusDays(1 - dayOfMonth).with(ChronoField.SECOND_OF_DAY, 0);
     LocalDateTime end = temp.plusDays(max - dayOfMonth).with(ChronoField.SECOND_OF_DAY, ChronoUnit.DAYS.getDuration().getSeconds() - 1);
     returnList.add(new Date[]{Date.from(start.toInstant(ZoneOffset.of("+8"))),Date.from(end.toInstant(ZoneOffset.of("+8")))});
     if(!ldt2.isBefore(start)&&!ldt2.isAfter(end)){
      break;
     }else{
      temp=temp.plusMonths(1);
     }
    }
    if(returnList.size()>0){
     Date[] firstEle=returnList.get(0);
     Date[] lastEle=returnList.get(returnList.size()-1);
     firstEle[0]=Date.from(ldt1.with(ChronoField.SECOND_OF_DAY,0).toInstant(ZoneOffset.of("+8")));
     lastEle[1]=Date.from(ldt2.with(ChronoField.SECOND_OF_DAY,0).toInstant(ZoneOffset.of("+8")));
    }
    break;
   }
  }
  return returnList;
 }
 /**
  * 计算两个时间相差多少日期单位(不足一个日期单位的的按一个日期单位算)
  *
  * @param d1 开始时间
  * @param d2 结束时间
  * @return 相差日期单位数
  */
 public static int getDiff(Date d1, Date d2, int calendarUnit) {
  double diff;
  switch (calendarUnit) {
   case Calendar.DATE: {
    diff = 1000 * 60 * 60 * 24;
    break;
   }
   case Calendar.HOUR_OF_DAY: {
    diff = 1000 * 60 * 60;
    break;
   }
   case Calendar.MINUTE: {
    diff = 1000 * 60;
    break;
   }
   case Calendar.SECOND: {
    diff = 1000;
    break;
   }
   default: {
    throw BaseRuntimeException.getException("[DateUtil.getDiff],Calendar Unit Not Support!");
   }
  }
  Long begin = d1.getTime();
  Long end = d2.getTime();
  Double res = (end - begin) / diff;
  return (int) Math.ceil(res);
 }
 /**
  * 会改变参数值
  * 格式化日期参数开始日期和结束日期
  * 格式规则为:
  * 开始日期去掉时分秒
  * 结束日期设置为当天 23:59:59
  *
  * @param startDate
  * @param endDate
  */
 public static void formatDateParam(Date startDate, Date endDate) {
  if (startDate != null) {
   startDate.setTime(getFloorDate(startDate, Calendar.DATE).getTime());
  }
  if (endDate != null) {
   Date tempDate = getCeilDate(endDate, Calendar.DATE);
   Calendar endC = Calendar.getInstance();
   endC.setTime(tempDate);
   endC.add(Calendar.SECOND, -1);
   endDate.setTime(endC.getTimeInMillis());
  }
 }
 /**
  * 获取一个日期的数字表示形式
  * 例如:
  * 2018-3-12 15:13:12 888 表示成 20180312151312888
  *
  * @param date
  * @param calendarUnit 最小的日期单位
  * @return
  */
 public static Long getDateNum(Date date, int calendarUnit) {
  if (date == null) {
   return null;
  }
  StringBuffer sb = new StringBuffer();
  Calendar c = Calendar.getInstance();
  c.setTime(date);
  if (calendarUnit >= Calendar.YEAR) {
   sb.append(c.get(Calendar.YEAR));
  }
  if (calendarUnit >= Calendar.MONTH) {
   sb.append(FormatUtil.formatToString(c.get(Calendar.MONTH) + 1, "00"));
  }
  if (calendarUnit >= Calendar.DATE) {
   sb.append(FormatUtil.formatToString(c.get(Calendar.DATE), "00"));
  }
  if (calendarUnit >= Calendar.HOUR_OF_DAY) {
   sb.append(FormatUtil.formatToString(c.get(Calendar.HOUR_OF_DAY), "00"));
  }
  if (calendarUnit >= Calendar.MINUTE) {
   sb.append(FormatUtil.formatToString(c.get(Calendar.MINUTE), "00"));
  }
  if (calendarUnit >= Calendar.SECOND) {
   sb.append(FormatUtil.formatToString(c.get(Calendar.SECOND), "00"));
  }
  if (calendarUnit >= Calendar.MILLISECOND) {
   sb.append(FormatUtil.formatToString(c.get(Calendar.MILLISECOND), "000"));
  }
  return Long.parseLong(sb.toString());
 }
 /**
  * 判断两个日期是否相等
  *
  * @param d1
  * @param d2
  * @param calendarUnit 对比的最小日期单位
  * @return
  */
 public static boolean isEqual(Date d1, Date d2, int calendarUnit) {
  Calendar c1 = Calendar.getInstance();
  Calendar c2 = Calendar.getInstance();
  c1.setTime(d1);
  c2.setTime(d2);
  for (int i = DATE_UNIT_ARR.length - 1; i >= 0; i--) {
   if (calendarUnit >= DATE_UNIT_ARR[i]) {
    int v1 = c1.get(DATE_UNIT_ARR[i]);
    int v2 = c2.get(DATE_UNIT_ARR[i]);
    if (v1 != v2) {
     return false;
    }
   } else {
    break;
   }
  }
  return true;
 }
 /**
  * 获取当天初始时间
  *
  * @param date 时间
  * @return 初始时间 (yyyy-MM-dd 00:00:00)
  */
 public static Date getInitialTime(Date date) {
  DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd 00:00:00");
  String dateStr = dateFormat.format(date);
  try {
   return dateFormat.parse(dateStr);
  } catch (ParseException e) {
   e.printStackTrace();
  }
  return null;
 }
 /**
  * 获取当天最后时间
  *
  * @param date 时间
  * @return 最后时间 (yyyy-MM-dd 23:59:59)
  */
 public static Date getTerminalTime(Date date) {
  DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
  String dateStr = dateFormat.format(date);
  dateStr = dateStr + " 23:59:59";
  dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  try {
   return dateFormat.parse(dateStr);
  } catch (ParseException e) {
   e.printStackTrace();
  }
  return null;
 }
 public static String date2Str(Date date) {
  DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  return dateFormat.format(date);
 }
 /**
  * 计算两个时间间隔多少秒
  *
  * @param startDate
  * @param endDate
  * @return
  */
 public static Long intervalTime(Date startDate, Date endDate) {
  long a = endDate.getTime();
  long b = startDate.getTime();
  Long c = ((a - b) / 1000);
  return c;
 }
 /**
  * 检测一个日期是否在 小时之内,支持跨天的小时
  *
  * @param time
  * @param startDate
  * @param endDate
  * @return
  */
 public static boolean checkDateIn(Date time, Date startDate, Date endDate) {
  if (startDate == null || endDate == null || time == null) {
   return true;
  }
  return time.before(endDate) && time.after(startDate);
 }
 /**
  * 检测一个日期是否在 时分秒 之内,支持跨天的小时
  *
  * @param time
  * @param startHms
  * @param endHms
  * @return
  */
 public static boolean checkHmsIn(Date time, String startHms, String endHms) {
  if (startHms == null || endHms == null || time == null) {
   return true;
  }
  LocalTime startTime = LocalTime.of(
    Integer.valueOf(startHms.substring(0, 2)),
    Integer.valueOf(startHms.substring(2, 4)),
    Integer.valueOf(startHms.substring(4, 6))
  );
  LocalTime endTime = LocalTime.of(
    Integer.valueOf(endHms.substring(0, 2)),
    Integer.valueOf(endHms.substring(2, 4)),
    Integer.valueOf(endHms.substring(4, 6))
  );
  LocalTime curTime = LocalDateTime.ofInstant(time.toInstant(), ZoneId.of("+8")).toLocalTime();
  if (endTime.isAfter(startTime)) {
   return startTime.isBefore(curTime) && endTime.isAfter(curTime);
  } else {
   return (startTime.isBefore(curTime) && LocalTime.MAX.isAfter(curTime)) || (LocalTime.MIN.isBefore(curTime) && endTime.isAfter(curTime));
  }
 }
 /**
  * 功能描述：格式化日期
  *
  * @param dateStr 字符型日期：YYYY/MM/DD 格式
  * @return Date 日期
  */
 public static Date parseDate(String dateStr) {
  return parseDate(dateStr, "yyyy-MM-dd");
 }
 /**
  * 功能描述：格式化日期
  *
  * @param dateStr 字符型日期
  * @param format 格式
  * @return Date 日期
  */
 public static Date parseDate(String dateStr, String format) {
  try {
   dateFormat = new SimpleDateFormat(format);
   String dt = dateStr.replaceAll("-", "/");
   if ((!dt.equals("")) && (dt.length() < format.length())) {
    dt += format.substring(dt.length()).replaceAll("[YyMmDdHhSs]",
      "0");
   }
   date = (Date) dateFormat.parse(dt);
  } catch (Exception e) {
   return null;
  }
  return date;
 }
 public static Date stringParseDate(String date) throws ParseException {
  //获取的值为"19570323"
  //1、定义转换格式
  SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
  SimpleDateFormat formatter2 = new SimpleDateFormat("yyyyMMdd");
  //2、调用formatter2.parse(),将"19570323"转化为date类型 输出为：Sat Mar 23 00:00:00 GMT+08:00 1957
  Date parseDate = formatter2.parse(date);
  return parseDate;
 }
}