JAVA Calendar Date Timestamp String-优快云博客

本文链接：https://blog.youkuaiyun.com/liuyuwen11/article/details/8440970

本文详细介绍如何在Java中进行日期和时间的各种转换操作，包括从Calendar到String、String到Calendar、Date到String、String到Date等多种转换方式，并展示了如何使用SimpleDateFormat进行格式化。

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http://dy-f.iteye.com/blog/1706697

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
1、Calendar -> String
Calendar calendat = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String dateStr = sdf.format(calendar.getTime());

2、String -> 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 -> String
SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");
String dateStr=sdf.format(new Date());

4、String -> Date
String str="2010-5-27";
SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");
Date birthday = sdf.parse(str);

5、Date -> Calendar
Calendar calendar = Calendar.getInstance();
calendar.setTime(new java.util.Date());

6、Calendar -> Date
Calendar calendar = Calendar.getInstance();
java.util.Date date =calendar.getTime();

7.Date -> String
System.out.println(sdf.format(new Date()));

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

9、Timestamp -> String
sdf.format(ts);

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 -> 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());