JSP建立自訂標籤庫

最後更新：2018-12-04 來源：互聯網

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自訂標籤庫描述符exampleTags.tld

<?xml version="1.0" encoding="UTF-8"?><taglib version="2.1" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd">  <tlib-version>1.0</tlib-version>  <short-name>example</short-name>  <description>自訂標籤庫描述</description>  <uri>/WEB-INF/tlds/exampleTags</uri>   <tag>   <name>iterate</name>   <tag-class>tags.FreeTag</tag-class>   </tag>   <tag>   <name>time</name>   <tag-class>tags.DateTag</tag-class>   </tag></taglib>

FreeTag.class

package tags;import java.io.IOException;import java.util.logging.Level;import java.util.logging.Logger;import javax.servlet.jsp.JspException;import javax.servlet.jsp.tagext.TagSupport;/** *  * @author jy */public class FreeTag extends TagSupport {    private int arrayCount = 0;    private String[] strings = null;        @Overridepublic int doStartTag() throws JspException{strings = (String[]) pageContext.getAttribute("strings");                return EVAL_BODY_INCLUDE;}            @Override        public int doAfterBody() throws JspException{            try {                pageContext.getOut().print(" "+strings[arrayCount] + "<br>");            } catch (IOException ex) {                Logger.getLogger(FreeTag.class.getName()).log(Level.SEVERE, null, ex);            }            arrayCount++;            if(arrayCount >= strings.length){                return SKIP_BODY;            }            return EVAL_BODY_AGAIN;        }}

DateTag.class

package tags;import java.io.IOException;import java.text.SimpleDateFormat;import java.util.logging.Level;import java.util.logging.Logger;import javax.servlet.jsp.tagext.TagSupport;/** * * @author jy */public class DateTag extends TagSupport {    @Override    public int doEndTag(){        SimpleDateFormat format = new SimpleDateFormat("HH:mm:ss");        String time = format.format(new java.util.Date());        try {            pageContext.getOut().print(time);        } catch (IOException ex) {            Logger.getLogger(DateTag.class.getName()).log(Level.SEVERE, null, ex);        }        return EVAL_PAGE;    }}

測試檔案test.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%><%@taglib prefix="example" uri="/WEB-INF/tlds/exampleTags.tld" %><!DOCTYPE html><html>    <head>        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">        <title>JSP Page</title>    </head>    <body>        <h1>Hello World!</h1>        <%        String[] strings = new String[]{"a","b","c"};        pageContext.setAttribute("strings", strings);        %>        <example:iterate>            now time:<example:time/>        </example:iterate>    </body></html>

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