标签：clu ansi 再计算 odi eval com img 自定义标签库 style
1、标签库的运作离不开tld文件
2、标签库的标签是定义在tld中的tag标签内（助手类）
标签的语言特点
<开始标签 属性="属性值">标签体</结束标签>
3. 自定义标签的开发及使用步骤
3.1 创建一个标签助手类(继承BodyTagSupport)
标签属性必须助手类的属性对应、且要提供对应get/set方法
3.2 创建标签库描述文件(tld)，添加自定义标签的配置
注：tld文件必须保存到WEB-INF目录或其子目录
3.3 在JSP通过taglib指令导入标签库，并通过指定后缀
访问自定义标签
4.标签生命周期
SKIP_BODY：跳过主体
EVAL_BODY_INCLUDE：计算标签主体内容并[输出]
EVAL_BODY_BUFFERED：计算标签主体内容并[缓存]
EVAL_PAGE:计算页面的后续部分
SKIP_PAGE:跳过页面的后续部分
EVAL_BODY_AGAIN:再计算主体一次
作业：
foreach标签的助手类：
package com.tag; import java.util.List; import javax.servlet.jsp.JspException; import javax.servlet.jsp.tagext.BodyTagSupport; public class ForeachTag extends BodyTagSupport{ /** * */ private static final long serialVersionUID = -961767522031795797L; private List<Object> itmes; private String var; public ForeachTag(List<Object> itmes, String var) { super(); this.itmes = itmes; this.var = var; } public ForeachTag() { super(); // TODO Auto-generated constructor stub } public List<Object> getItmes() { return itmes; } public void setItmes(List<Object> itmes) { this.itmes = itmes; } public String getVar() { return var; } public void setVar(String var) { this.var = var; } @Override public int doStartTag() throws JspException { // TODO Auto-generated method stub if (itmes==null) { return SKIP_BODY; } return EVAL_BODY_INCLUDE; } }
if标签的助手类：
package com.tag; import javax.servlet.jsp.JspException; import javax.servlet.jsp.tagext.BodyTagSupport; public class IfTag extends BodyTagSupport { /** * */ private static final long serialVersionUID = -5147827787787703458L; private boolean test; public boolean isTest() { return test; } public void setTest(boolean test) { this.test = test; } @Override public int doStartTag() throws JspException { if (!test) { return SKIP_BODY;//不显示标签中间的内容 } return EVAL_BODY_INCLUDE;//显示标签中的内容 } }
out标签的助手类：
package com.tag; import javax.servlet.jsp.JspException; import javax.servlet.jsp.JspWriter; import javax.servlet.jsp.tagext.BodyTagSupport; public class OutTag extends BodyTagSupport{ /** * */ private static final long serialVersionUID = -2971786012488394710L; private Object value; public Object getValue() { return value; } public void setValue(Object value) { this.value = value; } @Override public int doStartTag() throws JspException { JspWriter out = pageContext.getOut(); try { out.write(value.toString()); } catch (Exception e) { // TODO Auto-generated catch block throw new RuntimeException(e); } return SKIP_BODY; } }
set标签的助手类：
package com.tag; import javax.servlet.jsp.JspException; import javax.servlet.jsp.JspWriter; import javax.servlet.jsp.tagext.BodyTagSupport; public class SetTag extends BodyTagSupport{ /** * set标签 */ private static final long serialVersionUID = -5972588683307720977L; private Object value; public Object getValue() { return value; } public SetTag(Object value) { super(); this.value = value; } public void setValue(java.lang.Object value) { this.value=value; } public void setTarget(java.lang.Object target) { this.value=target; } @Override public int doStartTag() throws JspException { JspWriter out = pageContext.getOut(); try { out.write(value.toString()); } catch (Exception e) { // TODO Auto-generated catch block throw new RuntimeException(); } return SKIP_BODY; } }
自定义标签库：
<?xml version="1.0" encoding="UTF-8" ?>
<taglib xmlns="http://java.sun.com/JSP/TagLibraryDescrtiptor">
<tlib-version>1.1</tlib-version>
<jsp-version>1.2</jsp-version>
<short-name>Simple Tags</short-name>
<uri>/lingerqi</uri>
<tag>
<name>out</name>
<tag-class>com.tag.OutTag</tag-class>
<body-content>JSP</body-content>
<attribute>
<name>var</name>
<required>false</required>
<rtexprvalue>false</rtexprvalue>
</attribute>
</tag>
<tag>
<name>Foreach</name>
<tag-class>com.tag.ForeachTag</tag-class>
<body-content>JSP</body-content>
<attribute>
<name>var</name>
<required>false</required>
<rtexprvalue>false</rtexprvalue>
</attribute>
</tag>
<tag>
<name>if</name>
<tag-class>com.tag.IfTag</tag-class>
<body-content>JSP</body-content>
<attribute>
<name>var</name>
<required>false</required>
<rtexprvalue>false</rtexprvalue>
</attribute>
</tag>
<tag>
<name>set</name>
<tag-class>com.tag.SetTag</tag-class>
<body-content>JSP</body-content>
<attribute>
<name>value</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
</taglib>
调用标签：
<%@page import="java.util.ArrayList"%> <%@page import="java.util.List"%> <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib prefix="z" uri="/lingerqi" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <%-- <% List<String> ls = new ArrayList<>(); ls.add("zc"); ls.add("ls"); ls.add("ww"); ls.add("zl"); ls.add("so"); ls.add("wl"); pageContext.setAttribute("ls", ls); %> <ol> <l:foreach var="l" itmes="${ls }"> <li>${ls}</li> </l:foreach> </ol> --%> <%-- <z:out></z:out> --%> <%-- <z:if>{1>1}</z:if> --%> </body> </html>
标签：clu ansi 再计算 odi eval com img 自定义标签库 style
原文地址：https://www.cnblogs.com/omji0030/p/11037306.html
