Sharing of implementation examples of date processing classes in Java

This article mainly introduces the date processing class implemented by Java, and analyzes Java's related operation techniques for date acquisition, operation, conversion and other related operation techniques in the form of complete examples. Friends in need can refer to the examples of this article

Describes the date processing class implemented in Java. I share it with you for your reference. The details are as follows:

Dates are often used in development. Let’s summarize them as follows for future reference.

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class FormatTime {
  private final static SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMdd");
  private final static SimpleDateFormat sdfymdhm = new SimpleDateFormat("yyyyMMddHHmmss");
  private final static SimpleDateFormat sdfymdhms =  new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  /**
   *
  * @Title: getCurrentDay
  * @Description: TODO 获取当天时间(20161109)
  * @return
   */
  public static String getCurrentDay(){
    return sdf.format(new Date());
  }
  /**
   *
  * @Title: fTime2
  * @Description: TODO 获取time这个日期以前dayAgo天的日期
  * @return
   */
  public static String fTime(String time,int dayAgo){
    Date date = null;
    try {
      date = sdf.parse(time);
    } catch (ParseException e) {
        throw new RuntimeException(e);
    }
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    if(dayAgo>0){
      calendar.add(Calendar.DAY_OF_MONTH, -dayAgo);//前15天数据
      date = calendar.getTime();
      calendar.setTime(date);
    }
    int year=calendar.get(Calendar.YEAR);
    int month=calendar.get(Calendar.MONTH) + 1;
    int day = calendar.get(Calendar.DAY_OF_MONTH);
    String mon="";
    String d="";
    if(month<10){
      mon="0"+month;
    }else{
      mon=month+"";
    }
    if(day<10){
      d="0"+day;
    }else{
      d=""+day;
    }
    String ret=year+""+mon+""+d;
    return ret;
  }
  /**
   *
  * @Title: fTime2
  * @Description: TODO 获取time这个日期以后dayAfter天的日期
  * @return
   */
  public static String fTime2(String time,int dayAfter){
    Date date = null;
    try {
      date = sdf.parse(time);
    } catch (ParseException e) {
        throw new RuntimeException(e);
    }
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    if(dayAfter>0){
      calendar.add(Calendar.DAY_OF_MONTH, +dayAfter);//后15天数据
      date = calendar.getTime();
      calendar.setTime(date);
    }
    int year=calendar.get(Calendar.YEAR);
    int month=calendar.get(Calendar.MONTH) + 1;
    int day = calendar.get(Calendar.DAY_OF_MONTH);
    String mon="";
    String d="";
    if(month<10){
      mon="0"+month;
    }else{
      mon=month+"";
    }
    if(day<10){
      d="0"+day;
    }else{
      d=""+day;
    }
    String ret=year+""+mon+""+d;
    return ret;
  }
  /**
   *
  * @Title: getDefaultTime
  * @Description: TODO 获取昨天的日期
  * @return
   */
  public static String getDefaultTime(){
    Calendar calendar = Calendar.getInstance();
    calendar.add(Calendar.DAY_OF_MONTH, -1);//前1天
    Date date = calendar.getTime();
    String time=sdf.format(date);
    return time;
  }
  /**
   *
  * @Title: getSunday
  * @Description: TODO 获取最近一个星期天
  * @return
   */
  public static String getSunday(){
    SimpleDateFormat f = new SimpleDateFormat("yyyyMMdd");
    Calendar c = Calendar.getInstance();
    c.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
    return f.format(c.getTime());
  }
  /**
   *
  * @Title: getMonthFirstDay
  * @Description: TODO 获取本月第一天
  * @return
   */
  public static String getCurrentMonthFirstDay(){
    Calendar  cal_1=Calendar.getInstance();//获取当前日期
    cal_1.add(Calendar.MONTH, 0);
    cal_1.set(Calendar.DAY_OF_MONTH,1);//设置为1号,当前日期既为本月第一天
    String firstDay = sdf.format(cal_1.getTime());
    return firstDay;
  }
  /**
   *
  * @Title: getMonthFirstDay
  * @Description: TODO 获取上月第一天
  * @return
   */
  public static String getPreviousMonthFirstDay(){
   //获取当前月第一天：
  Calendar c = Calendar.getInstance();
  c.add(Calendar.MONTH, -1);
  c.set(Calendar.DAY_OF_MONTH,1);//设置为1号,当前日期既为本月第一天
  String first = sdf.format(c.getTime());
  return first;
  }
  /**
   *
  * @Title: getMonthFirstDay
  * @Description: TODO 获取上月最后一天
  * @return
   */
  public static String getPreviousMonthLastDay(){
  //获取当前月最后一天
  Calendar ca = Calendar.getInstance();
  ca.set(Calendar.DAY_OF_MONTH,0);//
  String lastDay = sdf.format(ca.getTime());
  return lastDay;
  }
  /**
   *
  * @Title: getCurrentMonthLastDay
  * @Description: TODO 获取指定时间最后一天
  * @return
   */
  public static String getCurrentMonthLastDay(String time){
    Date date =null;
   try {
    date= sdf.parse(time);
  } catch (ParseException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
  }
  //获取当前月最后一天
  Calendar ca = Calendar.getInstance();
  ca.setTime(date);
  ca.set(Calendar.DAY_OF_MONTH,
      ca.getActualMaximum(Calendar.DAY_OF_MONTH)); //
  String lastDay = sdf.format(ca.getTime());
  return lastDay;
  }
  /***
   *
  * @Title: getCurrentWeekDay
  * @Description: TODO 获取本周周一
   */
  public static String getCurrentMonday(){
     Calendar cal = Calendar.getInstance();
     cal.setFirstDayOfWeek(Calendar.MONDAY);//将每周第一天设为星期一，默认是星期天
     cal.add(Calendar.DATE, 0);
     cal.set(Calendar.DAY_OF_WEEK,Calendar.MONDAY);
     String monday = sdf.format(cal.getTime());
     return monday;
  }
  /***
   *
  * @Title: getPreviousSunday
  * @Description: TODO 获取上周周日
   */
  public static String getPreviousSunday(){
     Calendar cal = Calendar.getInstance();
     cal.setFirstDayOfWeek(Calendar.MONDAY);//将每周第一天设为星期一，默认是星期天
     cal.add(Calendar.DATE, -1*7);
     cal.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
     String sunday =sdf.format(cal.getTime());
     return sunday;
  }
  /**
   *
  * @Title: getMiniSencond
  * @Description: TODO 将日期转换为毫秒数
  * @param str
  * @return
   */
  public static String getMiniSencond(String str){
    long millionSeconds=0;
    try {
      millionSeconds = sdfymdhm.parse(str).getTime();//毫秒
    } catch (ParseException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    return millionSeconds+"";
  }
   /**
   *
  * @Title: getDateSencond
  * @Description: TODO 将日期转换为毫秒数
  * @param str
  * @return
   */
  public static long getDateSencond(String str){
    long millionSeconds=0;
    try {
      millionSeconds = sdfymdhms.parse(str).getTime();//毫秒
    } catch (ParseException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    return millionSeconds;
  }
  /**
   * 计算日期相差天数
   * @param str1
   * @param str2
   * @return
   */
  public static int getDistanceOfTwoDate(String str1,String str2){
    int result=0;
    try{
      Date date1 = sdf.parse(str1);
      Date date2 =sdf.parse(str2);
      Calendar aCalendar = Calendar.getInstance();
        aCalendar.setTime(date1);
        int day1 = aCalendar.get(Calendar.DAY_OF_YEAR);
        aCalendar.setTime(date2);
        int day2 = aCalendar.get(Calendar.DAY_OF_YEAR);
        result = day1-day2;
    }catch(Exception e){
      e.printStackTrace();
    }
    return result;
  }
  /**
   *
  * @Title: long2Date
  * @Description: TODO long 转日期(年-月-日 时-分-秒)
  * @param timestamp
  * @return
   */
  public static String longToDate(Long msecond){
    Date date = new Date(msecond);
    return sdfymdhms.format(date);
  }
}

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