Java 时间工具类-白红宇

Java 时间工具类

阅读量：5273 次

发布时间：2019-06-14

本文共 6158 字，大约阅读时间需要 20 分钟。

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

1.Calendar 转化 String

//获取当前时间的具体情况,如年,月,日,week,date,分,秒等

Calendar calendat = Calendar.getInstance();

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

String dateStr = sdf.format(calendar.getTime());

2.String 转化Calendar

String str="2010-5-27";

SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");

Date date =sdf.parse(str);

Calendar calendar = Calendar.getInstance();

calendar.setTime(date);

3.Date 转化String

SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");

String dateStr=sdf.format(new Date());

4.String 转化Date

String str="2010-5-27";

SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");

Date birthday = sdf.parse(str);

5.Date 转化Calendar

Calendar calendar = Calendar.getInstance();

calendar.setTime(new java.util.Date());

6.Calendar转化Date

Calendar calendar = Calendar.getInstance();

java.util.Date date =calendar.getTime();

7.Date 转成 String

System.out.println(sdf.format(new Date()));

8.String 转成 Timestamp

Timestamp ts = Timestamp.valueOf("2011-1-14 08:11:00");

9.Timestamp 转成 String

sdf.format(ts);

Timestamp和Date多数用法是一样的。

10.Date 转 TimeStamp

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

String time = df.format(new Date());

Timestamp ts = Timestamp.valueOf(time);

11.日期比较大小

String ti="2010-11-25 20:11:00";

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

Date time=sdf.parse(ti);

String ti2="2011-11-26 20:11:00";

Date time2=sdf.parse(ti2);

int c=ti2.compareTo(ti);

if(c>0){

System.out.println(ti+"大");

}else if(c==0){

System.out.println("一样大");

}else{

System.out.println(ti2+"大");

}

12.Date/ Timestamp 转成 Calendar

Calendar calendar = Calendar.getInstance();

calendar.setTime(startDate);

calendar.add(Calendar.YEAR, 2); //日期加2年

System.out.println(calendar.getTime());

calendar.add(Calendar.DATE, -30); //日期加30天

System.out.println(calendar.getTime());

calendar.add(Calendar.MONTH, 3); //日期加3个月

System.out.println(calendar.getTime());

13.将毫秒数转为String

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

Timestamp scurrtest = new Timestamp(millis);

String time=sdf.format(scurrtest);

public static String convert(Timestamp time) {

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

String result = df.format((Date) time);

return result;

}

public static Timestamp getNow() {

Date date = new Date();

SimpleDateFormat simDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

Timestamp now=Timestamp.valueOf(simDate.format(date));

return now;

}

public static String dateConvertToString(Date date){

SimpleDateFormat formatter = new SimpleDateFormat( "yyyy-MM-dd ");

String time = formatter.format(date);//格式化数据

return time;

}

　　　　//根据传入的日期计算距今多少天

　　　　public static Integer getValidDays(Date date){

　　　　　　　　int days=0;

　　　　　　　　Date now=new Date();

　　　　　　　　int i = now.compareTo(date);

　　　　　　　　if (i>0) {

　　　　　　　　　　return 0;

　　　　　　　　}else{

　　　　　　　　　　days = (int) Math.abs((now.getTime() - date.getTime())

　　　　　　　　　　/ (24 * 60 * 60 * 1000));

　　　　　　　　}

　　　　　　　return days;

　　　　　}

public static Long getTime(){

Date dt= new Date();

Long time= dt.getTime();

return time;

}

public static Calendar convertToCalendar(String date) throws ParseException{

Date d = new SimpleDateFormat("yyyy-MM-dd").parse(date);

Calendar cal=Calendar.getInstance();

cal.setTime(d);

return cal;

}

public static void main(String[] args) throws ParseException {

Calendar now = Calendar.getInstance();

System.out.println("年: " + now.get(Calendar.YEAR));

System.out.println("月: " + (now.get(Calendar.MONTH) + 1) + "");

System.out.println("日: " + now.get(Calendar.DAY_OF_MONTH));

System.out.println("时: " + now.get(Calendar.HOUR_OF_DAY));

System.out.println("分: " + now.get(Calendar.MINUTE));

System.out.println("秒: " + now.get(Calendar.SECOND));

System.out.println("当前时间毫秒数：" + now.getTimeInMillis());

System.out.println("当前月的天数：" + now.getActualMaximum(Calendar.DATE));

System.out.println(now.getTime());

//给定日期查看最大数

now.set(Calendar.YEAR,2002);

now.set(Calendar.MONTH,6);//7月

int maxDate = now.getActualMaximum(Calendar.DATE);

Date d = new Date();

System.out.println(d);

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

String dateNowStr = sdf.format(d);

System.out.println("格式化后的日期：" + dateNowStr);

String str = "2012-1-13 17:26:33"; //要跟上面sdf定义的格式一样

Date today = sdf.parse(str);

System.out.println("字符串转成日期：" + today);

}

/**  * 计算两个日期之间的天数  */ public class DateUtils {
     public static Integer daysBetween(Date smdate, Date bdate){
        try{
           SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");          smdate=sdf.parse(sdf.format(smdate));          bdate=sdf.parse(sdf.format(bdate));          Calendar cal = Calendar.getInstance();          cal.setTime(smdate);          long time1 = cal.getTimeInMillis();          cal.setTime(bdate);          long time2 = cal.getTimeInMillis();          long between_days=(time2-time1)/(1000*3600*24);          return Integer.parseInt(String.valueOf(between_days));       }catch (Exception e){
           throw new RuntimeException("The Date sub error");       }    }

/**  * 自然年加法  * @param date  * @return  */ public static Date getAddDate(Date date,Integer year){
     try{
        Calendar calendar = Calendar.getInstance();       calendar.setTime(date);       calendar.add(Calendar.YEAR, year);       date = calendar.getTime();       SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");       String dateStr = simpleDateFormat.format(date);       Date parse = simpleDateFormat.parse(dateStr);       return parse;    }catch (Exception e){
        throw new RuntimeException("The Date add error");    } } 　　　　/**

*

* @param 要转换的毫秒数

* @return 该毫秒数转换为 * days * hours * minutes * seconds 后的格式

* @author fy.zhang

*/

public

static

String formatDuring(

long