Date related code

Date issue

When you change a string to a date, be aware that the format matches the line.

1. Get server-side current date:
<%@ page import= "Java.util.Date"%>
<%
Date mydate = new Date ();
%>

2, to obtain the current year, month, 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 current date by local time zone
<%@ page import= "Java.util.Date"%>
<%
Date mydate = new Date ();
Out.println (Mydate.tolocalestring ());
%>
The output results are:
2003-5-30

4, to get the database in the field name "Publish_time", type datetime value
<%@ page import= "Java.util.Date"%>
<%
... Connect database ...
ResultSet rs = ...
Date sdate = rs.getdate ("Publish_time");
%>
[Code]

5. Print date in specified format (date to string)
[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 results of the output are:
It is Friday 2003.05.30 at 11:30:46 a.m. CST
(See the SimpleDateFormat class for more detailed formatting symbols)

6. Convert a string to a date
<%@ page import= "Java.util.Date"%>
<%@ page import= "Java.text.DateFormat"%>
<%
String input = "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);
}
%>
The output results are:
Fri Nov 00:00:00 CST 1222

7. Calculate the interval between dates
<%@ page import= "Java.util.Date"%>
<%@ page import= "Java.text.DateFormat"%>
<%
String input = "2003-05-01";
SimpleDateFormat formatter = new SimpleDateFormat ("Yyyy-mm-dd");
Date D1 = null;
try{
D1 = formatter.parse (input);
}catch (ParseException e) {
Out.println ("unparseable using" + formatter);
}

Date D2 = new Date ();

Long diff = d2.gettime ()-d1.gettime ();
Out.println ("difference is" + (diff/(1000*60*60*24)) + "days.");
%>
The output results are:
Difference is.

8, date of addition and subtraction operation
Method: Using 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 ()));
%>
The output results are:
It is now Friday 2003.05.30 at 01:45:32 pm CST
Two years ago was Wednesday 2001.05.30 at 01:45:32 pm CST

9. Comparison Date
Method: Using Equals (), before (), after () method
<%@ page import= "java.util.*"%>
<%@ page import= "java.text.*"%>
<%
DateFormat df = new SimpleDateFormat ("Yyy-mm-dd");
Date D1 = df.parse ("2000-01-01");
Date D2 = Df.parse ("1999-12-31");

String relation = null;
if (D1.equals (D2))
Relation = "The same date as";
else if (D1.before (D2))
Relation = "before";
Else
Relation = "after";
Out.println (D1 + "is" + relation + "+ D2);
%>
The output results are:
Sat 00:00:00 CST Fri Dec 00:00:00 CST 1999

10. Record the time spent on one thing
Method: Call two times System.gettimemillis () method, find the difference value
<%@ page import= "java.text.*"%>
<%
Long t0,t1;
T0 = System.currenttimemillis ();
Out.println ("Cyc starts at" + t0);
int k = 0;
for (int i =0;i<100000;i++) {
K = i;
}
T1 = System.currenttimemillis ();
Out.println ("<br>");
Out.println ("Cyc ends at" + T1);
Out.println ("<br>");
Out.println ("This run took" + (T1-T0) + "Ms.");
%>

The output results are:
CYC starts at 1054275312432
Cyc ends at 1054275312442
This run took 10ms.

Other: How to format decimal

<%@ page import= "java.text.*"%>
<%
DecimalFormat df = new DecimalFormat (", ###.00");
Double anumber = 33665448856.6568975;
String result = Df.format (anumber);
OUT.PRINTLN (result);
%>

The output results are:
33,665,448,856.66

======================

Date comparison:

The calculation and comparison of dates in Java can be resolved using date and DateFormat, and here is a sample code:

Import java.text.*;
Import java.util.*;

public class test{

public static void Main (string[] args) {
try{
Date Date=new date ();
DateFormat df=dateformat.getdatetimeinstance ();
String Now=df.format (date);
System.out.println ("Now Time:" +now);

System.out.println ("Now Time is before 16:00:" +date.before (Df.parse ("2004-12-24 16:00:00"));
}
catch (ParseException e) {System.out.print (E.getmessage ());
}
}
}

<%= ("" +equipmentbuyinfo.getbuydate ()). Equals ("null")? "":( Equipmentbuyinfo.getbuydate (). toString ()). substring (0,10)%>

(New SimpleDateFormat ("Yyyy-mm-dd hh:mm")). Format (Abean.getuploaddate ())