Java 时间工具类
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 mss) {
long days = mss / (1000 * 60 * 60 * 24);
long hours = (mss % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60);
long minutes = (mss % (1000 * 60 * 60)) / (1000 * 60);
long seconds = (mss % (1000 * 60)) / 1000;
return days + " days " + hours + " hours " + minutes + " minutes "
+ seconds + " seconds ";
}
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