自定义一个很简单的jsp标签-百家乐凯发k8

web 工程，新建java类：

[java]  package leon.webtest.tags; 
 
import java.text.simpledateformat; 
import java.util.date; 
 
import javax.servlet..jspexception; 
import javax.servlet.jsp.jspwriter; 
import javax.servlet.jsp.tagext.tagsupport; 
 
 
public class datetime extends tagsupport { 
 
    private static final long serialversionuid = 1l; 
 
    public int dostarttag() throws jspexception { 
        try { 
            jspwriter out = this.pagecontext.getout(); 
             
            simpledateformat sdf = new simpledateformat("yyyy-mm-dd hh:mm:ss"); 
             
            out.println(""); 
            out.println(sdf.format(new date())); 
            out.println(""); 
 
        } catch (exception e) { 
            throw new jspexception(e.getmessage()); 
        } 
        return skip_body; 
    } 
} 

package leon.webtest.tags;

import java.text.simpledateformat;
import java.util.date;

import javax.servlet.jsp.jspexception;
import javax.servlet.jsp.jspwriter;
import javax.servlet.jsp.tagext.tagsupport;

public class datetime extends tagsupport {

 private static final long serialversionuid = 1l;

 public int dostarttag() throws jspexception {
  try {
   jspwriter out = this.pagecontext.getout();
   
   simpledateformat sdf = new simpledateformat("yyyy-mm-dd hh:mm:ss");
   
   out.println("");
   out.println(sdf.format(new date()));
   out.println("");

  } catch (exception e) {
   throw new jspexception(e.getmessage());
  }
  return skip_body;
 }
}
新建tld文件：web-inf/tld/webtest-tags.tld

[html]   
    xmlns:xsi="https://www.w3.org/2001/xmlschema-instance" 
    xsi:schemallocation="http://www.51sjk.com/upload/articles/1/0/248/248955_20210624001200531.jpg web-jsptaglibrary_2_0.xsd" 
    version="2.0"> 
 
    a tag library exercising simpletag handlers. 
    1.0 
    examples 
    /mytags 
    jsp self-define tag library. 
 
     
        this is an date time tag 
        datetime 
        leon.webtest.tags.datetime 
        empty 
     
 

 xmlns:xsi="https://www.w3.org/2001/xmlschema-instance"
 xsi:schemallocation="http://www.51sjk.com/upload/articles/1/0/248/248955_20210624001200531.jpg web-jsptaglibrary_2_0.xsd"
 version="2.0">

 a tag library exercising simpletag handlers.
 1.0
 examples
 /mytags
 jsp self-define tag library.

 
  this is an date time tag
  datetime
  leon.webtest.tags.datetime
  empty
 

web.xml中的配置：

[html]  
    xmlns="http://www.51sjk.com/upload/articles/1/0/248/248955_20210624001200531.jpg"  
    xmlns:xsi="https://www.w3.org/2001/xmlschema-instance"  
    xsi:schemalocation="http://www.51sjk.com/upload/articles/1/0/248/248955_20210624001200531.jpg http://www.51sjk.com/upload/articles/1/0/248/248955_20210624001200531.jpg/web-app_2_4.xsd"> 
     
    webtest 
     
     
        index.html 
        index.jsp 
     
     
     
         
            /mytags 
            /web-inf/tld/webtest-tag.tld 
             
         
     
 

 xmlns="http://www.51sjk.com/upload/articles/1/0/248/248955_20210624001200531.jpg"
 xmlns:xsi="https://www.w3.org/2001/xmlschema-instance"
 xsi:schemalocation="http://www.51sjk.com/upload/articles/1/0/248/248955_20210624001200531.jpg http://www.51sjk.com/upload/articles/1/0/248/248955_20210624001200531.jpg/web-app_2_4.xsd">
 
 webtest
 
 
  index.html
  index.jsp
 
 
 
  
   /mytags
   /web-inf/tld/webtest-tag.tld
   
  
 

jsp中的使用：

首先是导入：

<%@ taglib uri="/mytags" prefix="leon" %>

使用标签：

加强版：需要显示出来的时间是动态的，像时钟一样会跳秒的。