Java date conversion simpledateformat format Daquan and judge whether it is a legal Date and Time string?

Source: Internet
Author: User
24-hour time display:

public class Datetime {

    public static void main(String args[]){
         java.util.Date current=new java.util.Date();
           java.text.SimpleDateFormat sdf=new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
           String c=sdf.format(current);
           System.out.println(c);
    }
}

12-hour time display:


public class Datetime {

    public static void main(String args[]){
         java.util.Date current=new java.util.Date();
           java.text.SimpleDateFormat sdf=new java.text.SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
           String c=sdf.format(current);
           System.out.println(c);
    }
}

Difference: yyyy-mm-dd hh: mm: SS; yyyy-mm-dd hh: mm: SS

As follows:

Letter Date or time element Indicates Example
G Era identifier Text AD
y Year Year 1996;96
M Month in Year Month July;Jul;07
w Week in Year Number 27
W The number of weeks in the month Number 2
D Days in years Number 189
d Days in a month Number 10
F Week in the month Number 2
E Days in a week Text Tuesday;Tue
a AM/PM mark Text PM
H Hours in a day (0-23) Number 0
k Hours per day (1-24) Number 24
K Hours in AM/PM (0-11) Number 0
h Hours in AM/PM (1-12) Number 12
m Minutes in an hour Number 30
s Seconds in minutes Number 55
S Milliseconds Number 978
z Time Zone General Time Zone Pacific Standard Time;PST;GMT-08:00
Z Time Zone RFC 822 Time Zone -0800

-------------------------------------------------------------

Public class judgedate {

/**
* Judge whether it is a valid date and time string
* @ Param str_input
* @ Return Boolean; true: false.
*/
Public static Boolean isdate (string str_input, string rdateformat ){
If (! Isnull (str_input )){
Simpledateformat formatter = new simpledateformat (rdateformat );
Formatter. setlenient (false );
Try {
Formatter. Format (formatter. parse (str_input ));
} Catch (exception e ){
Return false;
}
Return true;
}
Return false;

}
Public static Boolean isnull (string Str ){
If (STR = NULL)
Return true;
Else
Return false;
}
Public static void main (string ARGs []) {
String STR = "2007-5-12 ";
If (isdate (STR, "YYYY. Mm. dd") | isdate (STR, "yyyy-mm-dd "))
System. Out. Print ("this is true ");
Else
System. Out. println (STR );
}
}

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