Java date Processing

Java date Processing

1. Get the current server Date:

<% @ Page import = "Java. util. Date" %>
<%
Date mydate = new date ();
%>

 

2. Obtain the current year, month, and day:

<% @ Page import = "Java. util. Date" %>

<%
Date mydate = new date ();
Int Thisyear = mydate. getyear () + 1900; // Thisyear = 2003
Int thismonth = mydate. getmonth () + 1; // thismonth = 5
Int thisdate = mydate. getdate (); // thisdate = 30
%>

3. output the current date by local time zone

<% @ Page import = "Java. util. Date" %>
<%
Date mydate = new date ();
Out. println (mydate. tolocalestring ());
%>

Output result:
2003-5-30

4. Obtain the value of "publish_time" and datetime type in the database.

<% @ Page import = "Java. util. Date" %>
<%
... Connect to the database...
Resultset rs =...
Date sdate = Rs. getdate ("publish_time ");
%>
[Code]

5. Print the date in the specified format

[Code]
<% @ Page import = "Java. util. Date" %>
<% @ Page import = "Java. Text. dateformat" %>
<%
Date dnow = new date ();

Simpledateformat formatter = new simpledateformat ("e YYYY. Mm. dd' at 'hh: mm: ss a Zzz ");
Out. println ("it is" + formatter. Format (dnow ));
%>

 

The output result is:
It is Friday 2003.05.30 at 11:30:46 am CST
(For more detailed format symbols, see simpledateformat)

6. convert a string to a date

<% @ Page import = "Java. util. Date" %>
<% @ Page import = "Java. Text. dateformat" %>
<%
String inputs = "1222-11-11 ";
Simpledateformat formatter = new simpledateformat ("yyyy-mm-dd ");
Date T = NULL;

Try ...{

T = formatter. parse (input );

Out. println (t );

} Catch (parseexception e )...{

Out. println ("unparseable using" + formatter );

}

%>

 

Output result:
Fri Nov 11 00:00:00 CST 1222

7. Between calculation dates

Output result:
Difference is 29 days.

8. addition and subtraction of dates
Method: Use the add () method of the calendar class

<% @ Page import = "Java. util. *" %>
<% @ Page import = "Java. Text. *" %>
<%
Calendar now = calendar. getinstance ();
Simpledateformat formatter = new simpledateformat ("e YYYY. Mm. dd' at 'hh: mm: ss a Zzz ");
Out. println ("it is now" + formatter. Format (now. gettime ()));
Now. Add (calendar. day_of_year,-(365*2 ));
Out. println ("<br> ");
Out. println ("two years ago was" + formatter. Format (now. gettime ()));
%>

 

Output result:
It is now Friday 2003.05.30 at 01:45:32 pm CST
Two years ago was wed2001.05.30 at 01:45:32 pm CST

9. Comparison date
Method: Use the equals (), before (), and after () methods.

1. <% @ Page import = "Java. util. *" %>
2. <% @ Page import = "Java. Text. *" %>
3. <%
4. Dateformat df = new simpledateformat ("yyy-mm-dd ");
5. Date d1 = DF. parse ("2000-01-01 ");
6. Date D2 = DF. parse ("maid ");
8. String relation = NULL;
9. If (d1.equals (D2 ))
10. Relation = "the same date ";
11. Else if (d1.before (D2 ))
12. Relation = "before ";
13. Else
14. Relation = "after ";
15. Out. println (d1 + "is" + Relation + ''+ D2 );
16. %>

Output result:
Sat Jan 01 00:00:00 CST 2000 is after Fri Dec 31 00:00:00 CST 1999

10. record the time spent on one thing
Method: Call the system. gettimemillis () method twice to calculate the difference value.

1. <% @ Page import = "Java. Text. *" %>
2. <%
3. Long T0, T1;
4. T0 = system. currenttimemillis ();
5. Out. println ("Cyc starts at" + T0 );
6. Int K = 0;
7. For (INT I = 0; I <100000; I ++)
8. T1 = system. currenttimemillis ();
9. Out. println ("<br> ");
10. Out. println ("Cyc ends at" + T1 );
11. Out. println ("<br> ");
12. Out. println ("this run took" + (t1-t0) + "ms .");
13. %>

Output result:

1. Cyc starts 1054275312432
2. Cyc ends 1054275312442
3. This run took 10 ms.
5. Others: how to format Decimals
7. <% @ Page import = "Java. Text. *" %>
8. <%
9. Decimalformat df = new decimalformat (", ###. 00 ");
10. Double anumber = 33665448856.6568975;
11. String result = DF. Format (anumber );
12. Out. println (result );
13. %>

Output result:
33,665,448,856.66