JSP develops custom labels, custom labels convert strings to the specified time format display

This example converts the time in string format to the specified time format display.

The first step, define a label handler class, needs to integrate Javax.servlet.jsp.tagext.TagSupport, the code is as follows:

Importjava.io.IOException;ImportJava.text.SimpleDateFormat;ImportJava.util.Calendar;Importjavax.servlet.jsp.JspException;ImportJavax.servlet.jsp.tagext.TagSupport;/*** Custom time-processing labels * */ Public classJstldatetagextendsTagSupport {/**     *      */    Private Static Final LongSerialversionuid = -8683014812426654300l; PrivateString value;//corresponds to value in JSTL expressionPrivateString parttern;//The time format specified by Partern in the corresponding expression Public intdoStartTag ()throwsjspexception {String VV=string.valueof (value); LongTime =long.valueof (VV); Calendar C=calendar.getinstance ();        C.settimeinmillis (time); SimpleDateFormat DateFormat=NewSimpleDateFormat (Parttern); String s=Dateformat.format (C.gettime ()); Try{pagecontext.getout (). write (s); } Catch(IOException e) {e.printstacktrace (); }        return Super. doStartTag (); }     PublicString GetValue () {returnvalue; }     Public voidSetValue (String value) { This. Value =value; }     PublicString Getparttern () {returnParttern; }     Public voidSetparttern (String parttern) { This. Parttern =Parttern; }}

Step Two, write a file in TLD format. (a file formatted like an XML format) is as follows: Dateformat.tld

<?XML version= "1.0" encoding= "UTF-8"?><taglib>    <tlib-version>1.1</tlib-version>    <jsp-version>1.2</jsp-version>    <Short-name>Date</Short-name>    <Tag>        <name>Stringtodate</name>        <Tag-class>Com.xxx.JSTLDateTag</Tag-class><!--The label you just wrote.        <attribute>            <name>Value</name>            <Required>True</Required>            <Rtexprvalue>True</Rtexprvalue>        </attribute>        <attribute>            <name>Parttern</name>            <Required>True</Required>            <Rtexprvalue>True</Rtexprvalue>        </attribute>    </Tag></taglib>

The third step, add the configuration in Web. XML, find the <jsp-config> node join <taglib> configuration in Web. XML, the code is as follows:

    <Jsp-config>        <taglib>            <Taglib-uri>Http://java.sun.com/jsp/jstl/core</Taglib-uri>            <taglib-location>/web-inf/tld/c.tld</taglib-location>        </taglib>         <!--Custom Jstl time formatting -       <taglib>                   <Taglib-uri>/datetag</Taglib-uri> <!-- take note of the '/datetag ' here.                <taglib-location>/web-inf/tld/dateformat.tld</taglib-location>                   </taglib>       </Jsp-config>

The fourth step, use the custom label in the JSP page, as follows

 <  %@ taglib  uri  = "/datetag"   prefix  = "Fmtdate"  >  <  fmtdate:stringtodate  parttern  = "Yyyy-mm-dd HH:mm:ss"  " Span style= "color: #0000ff;" >= "${hotcontent.createdate}"  ></ fmtdate:stringtodate  >