javax.servlet.jsp.tagext里的类SimpleTagSupport
使用SimpleTagSupport类一网打尽以往复杂的标签开发,直接使用doTag()方法
java文件:
package org.lxh.tagdemo ; import java.io.* ; import java.util.* ; import java.text.* ; import javax.servlet.jsp.* ; import javax.servlet.jsp.tagext.* ; public class SimpleDateTag extends SimpleTagSupport { private String format ; // 接收格式化 public void doTag() throws JspException, IOException{ SimpleDateFormat sdf = new SimpleDateFormat(this.format) ; try{ super.getJspContext().getOut().write(sdf.format(new Date())) ; }catch(Exception e){} } public void setFormat(String format){ this.format = format ; } public String getFormat(){ return this.format ; } }
tlb文件:
<?xml version="1.0" encoding="UTF-8"?> <taglib xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_1.xsd" version="2.1"> <tlib-version>1.0</tlib-version> <short-name>mldntag</short-name> <tag> <name>simpledate</name> <tag-class>org.lxh.tagdemo.SimpleDateTag</tag-class> <body-content>empty</body-content> <attribute> <name>format</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> </tag> </taglib>
web.xml文件:
<jsp-config> <taglib> <taglib-uri>mldn</taglib-uri> <taglib-location>/WEB-INF/mldntag.tld</taglib-location> </taglib> </jsp-config>
jsp文件:
<%@ page contentType="text/html" pageEncoding="GBK"%> <%@ taglib prefix="mytag" uri="mldn"%> <html> <head><title>www.mldnjava.cn,MLDN高端Java培训</title></head> <body> <h1> <mytag:simpledate format="yyyy-MM-dd HH:mm:ss.SSS"/> </h1> </body> </html>
定义有属性的标签:
java 文件:format作为属性
package org.lxh.tagdemo ; import java.text.* ; import java.util.* ; import javax.servlet.jsp.* ; import javax.servlet.jsp.tagext.* ; public class DateTag extends TagSupport { private String format ; // 当设置属性的时候可以通过setter完成 public int doStartTag() throws JspException{ SimpleDateFormat sdf = new SimpleDateFormat(this.format) ; // 表示进行格式化的日期显示操作 try{ super.pageContext.getOut().write(sdf.format(new Date())) ; }catch(Exception e){ e.printStackTrace() ; // 异常处理操作 } return TagSupport.SKIP_BODY ; } public void setFormat(String format){ this.format = format ; } public String getFormat(){ return this.format ; } }
tld文件,定义属性format:
<?xml version="1.0" encoding="UTF-8"?> <taglib xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_1.xsd" version="2.1"> <tlib-version>1.0</tlib-version> <short-name>datetag</short-name> <tag> <name>date</name> <tag-class>org.lxh.tagdemo.DateTag</tag-class> <body-content>empty</body-content> <attribute> <name>format</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> </tag> </taglib>
web.xml:
<jsp-config> <taglib> <taglib-uri>mldn_date</taglib-uri> <taglib-location>/WEB-INF/datetag.tld</taglib-location> </taglib> </jsp-config>
JSP调用文件,format的setter通过反射机制完成:
<%@ page contentType="text/html" pageEncoding="GBK"%> <%@ taglib prefix="mytag" uri="mldn_date"%> <html> <head><title>www.mldnjava.cn,MLDN高端Java培训</title></head> <body> <h1><mytag:date format="yyyy-MM-dd HH:mm:ss.SSS"/></h1> </body> </html>