第 10 章 ： 自定义标签

编写步骤：

1. 标签处理类
2. 编写 tld 文件
3. taglib 导入 tld 文件

依赖

<dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>4.0.1</version> <scope>provided</scope>
</dependency>

<dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>javax.servlet.jsp-api</artifactId> <version>2.3.3</version> <scope>provided</scope>
</dependency>

  

 

  
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定义无内容标签

package com.pengshiyu.taglibs;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import java.io.IOException;

public class HelloTag extends SimpleTagSupport { @Override public void doTag() throws JspException, IOException { this.getJspContext().getOut().println("hello"); }
}


  

 

  
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声明

<?xml version="1.0" encoding="utf-8"?>

<taglib> <tlib-version>1.0</tlib-version> <jsp-version>2.0</jsp-version> <short-name>Example TLD with Body</short-name> <tag> <name>Hello</name> <tag-class>com.pengshiyu.taglibs.HelloTag</tag-class> <body-content>empty</body-content> </tag>
</taglib>

  

 

  
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引入声明文件并使用标签

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>

<%@ taglib prefix="ext" uri="WEB-INF/custom.tld" %>

<ext:Hello />

  

 

  
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定义有内容标签

package com.pengshiyu.taglibs;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import java.io.IOException;

public class HelloTag extends SimpleTagSupport { @Override public void doTag() throws JspException, IOException { JspWriter out = this.getJspContext().getOut(); out.write("******"); this.getJspBody().invoke(out); out.write("******"); }
}


  

 

  
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<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>

<%@ taglib prefix="ext" uri="WEB-INF/custom.tld" %>

<ext:Hello>
你好
</ext:Hello>

  

 

  
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输出

****** 你好 ******

  

 

  
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不再执行标签下面的内容

package com.pengshiyu.taglibs;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.SkipPageException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import java.io.IOException;

public class HelloTag extends SimpleTagSupport { @Override public void doTag() throws JspException, IOException { this.getJspContext().getOut().write("以下内容不显示"); throw new SkipPageException(); }
}


  

 

  
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带有属性的标签

标签类

package com.pengshiyu.taglibs;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import java.io.IOException;

public class HelloTag extends SimpleTagSupport { private String name = ""; public void setName(String name) { this.name = name; } @Override public void doTag() throws JspException, IOException { this.getJspContext().getOut().write(this.name); }
}


  

 

  
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tld 配置

<tag> <name>Hello</name> <tag-class>com.pengshiyu.taglibs.HelloTag</tag-class> <body-content>scriptless</body-content> <attribute>
<!-- 属性名称--> <name>name</name>
<!-- 是否可选--> <required>true</required>
<!-- 支持表达式--> <rtexprvalue>true</rtexprvalue> </attribute>
</tag>

  

 

  
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使用

<ext:Hello name="Tom"></ext:Hello>

  

 

  
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文章来源: pengshiyu.blog.csdn.net，作者：彭世瑜，版权归原作者所有，如需转载，请联系作者。

原文链接：pengshiyu.blog.csdn.net/article/details/106889113