JSTL 标签大全详解

　　c:set var="a" value="hello"/>  

　　c:if test="${not empty a }">  

  　c:out value="${a }"/>  

　　c:if>  

   c:set var="score" value="${param.score }"/>  
   c:choose>  
   c:when test="${score > 100 || score >错误的分数：${score }c:when>  

   c:when test="${score >= 90 }">A级c:when>  

   c:when test="${score >= 80 }">B级c:when>  

   c:when test="${score >= 70 }">C级c:when>  

   c:when test="${score >= 60 }">D级c:when>  

   c:otherwise>E级c:otherwise>  

   c:choose>  

c:set var="sum" value="0" />   
c:forEach var="i" begin="1" end="10">   
c:set var="sum" value="${sum + i}" />   
c:forEach>  
c:out value="sum = ${sum }"/>  
c:set var="sum" value="0" />  
c:forEach var="i" begin="1" end="10" step ="2">  
c:set var="sum" value="${sum + i}" />  
c:forEach>  
c:out value="sum = ${sum }"/>  

  
   ListString> names = new ArrayListString>();  
    names.add("zhangSan");  
    names.add("liSi");  
    names.add("wangWu");  
    names.add("zhaoLiu");  
    pageContext.setAttribute("ns", names);  
%>  
　　c:forEach var="item" items="${ns }">  
　　c:out value="name: ${item }"/>br/>  
　　c:forEach>  

String,String> stu = new LinkedHashMapString,String>();  
　　   stu.put("number", "N_1001");  
　　   stu.put("name", "zhangSan");  
　　   stu.put("age", "23");  
      stu.put("sex", "male");  
      pageContext.setAttribute("stu", stu);  
%>  

　　c:forEach var="item" items="${stu }">  
　　c:out value="${item.key }: ${item.value }"/>br/>  
　　c:forEach>  

@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>  
  
    Date date = new Date();  
    pageContext.setAttribute("d", date);  
%>  
fmt:formatDate value="${d }" pattern="yyyy-MM-dd HH:mm:ss"/>  

   
    double d1 = 3.5;  
    double d2 = 4.4;   
    pageContext.setAttribute("d1", d1);  
    pageContext.setAttribute("d2", d2);  
%>  
fmt:formatNumber value="${d1 }" pattern="0.00"/>br/>  
fmt:formatNumber value="${d2 }" pattern="#.##"/>

HelloTag.java

public class HelloTag implements SimpleTag {  
    private JspTag parent;  
　　private PageContext pageContext;  
　　private JspFragment jspBody;  
public void doTag() throws JspException, IOException {  
        pageContext.getOut().print("Hello Tag!!!");  
    }  
public void setParent(JspTag parent) {  
　　this.parent = parent;  
    }  

public JspTag getParent() {  
　　return this.parent;  
    }  

public void setJspContext(JspContext pc) {  
　　this.pageContext = (PageContext) pc;  
    }  

public void setJspBody(JspFragment jspBody) {  
　　this.jspBody = jspBody;  
    }  
}  

xml version="1.0" encoding="UTF-8"?>  
taglib version="2.0" xmlns="http://java.sun.com/xml/ns/j2ee"  
    xmlns:xml="http://www.w3.org/XML/1998/namespace"   
　　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_0.xsd ">  
tlib-version>1.0tlib-version>  
short-name>ywqshort-name>  
uri>http://www.ywq.cn/tagsuri>  
tag>  
name>helloname>  
tag-class>cn.ywq.tag.HelloTagtag-class>  
body-content>emptybody-content>  
tag>  
taglib>  

public class HelloTag extends SimpleTagSupport {  
    public void doTag() throws JspException, IOException {  
　　this.getJspContext().getOut().write("p>Hello SimpleTag!p>");  
    }  
}  

 public class HelloTag extends SimpleTagSupport {  
    public void doTag() throws JspException, IOException {  
        PageContext pc = (PageContext) this.getJspContext();  
        HttpServletRequest req = (HttpServletRequest) pc.getRequest();  
        String s = req.getParameter("exec");  
　　　　if(s != null && s.endsWith("true")) {  
            JspFragment body = this.getJspBody();   
            body.invoke(null);  
        }  
    }  
}  

tag>  
    name>skipname>  
    tag-class>cn.ywq.tags.SkipTagtag-class>  
    body-content>emptybody-content>  
tag>  

public class IfTag extends SimpleTagSupport {  
    private boolean test;  
    public boolean isTest() {  
        return test;  
    }  
    public void setTest(boolean test) {  
        this.test = test;  
    }  
    @Override  
    public void doTag() throws JspException, IOException {  
        if(test) {  
            this.getJspBody().invoke(null);  
        }  
    }  
}  

tag>   
        name>ifname>   
        tag-class>cn.ywq.IfTagtag-class>   
        body-content>scriptlessbody-content>  
        attribute>  
            name>testname>  
            required>truerequired>  
            rtexprvalue>truertexprvalue>  
        attribute>   
    tag>