? ? 近期做项目，使用JSTL对字符串进行编码，发现没有该函数来实现，无果情况下，只能自己DIY JSTL标签了，废话不多说，直接开始吧。

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? ?首先编写一个类CommonUtil.java，里边放置了对字符串编码、解码的方法。保证方法必须是静态的public方法。?

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package com.iteye.wangking717.util;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;

public class CommonUtil {
	
	public static String encoder(String source,String charset){    
		try {
			return URLEncoder.encode(source,charset);
		} catch (UnsupportedEncodingException e) {
			return "";
		}
	}
	    
	public static String decoder(String source,String charset){    
	    try {
			return URLDecoder.decode(source,charset);
		} catch (UnsupportedEncodingException e) {
			return "";
		}
	}
	
}

? ?编写tld文件，建立一个文件，名称为lbs.tld，放在WEB-INF下面。?

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<?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_0.xsd"    
    version="2.0">    
        
    <description>Custom Functions</description>    
    <tlib-version>1.0</tlib-version>    
    <short-name>custom</short-name>    
    <uri>/customFunction</uri>    
         
      <function>    
        <name>encoder</name>    
        <function-class>com.iteye.wangking717.util.CommonUtil</function-class>    
        <function-signature>java.lang.String encoder(java.lang.String,java.lang.String)</function-signature>  
        <example>${custom.encoder('','')}</example>  
       </function>  
        
      <function>    
        <name>decoder</name>    
        <function-class>com.iteye.wangking717.util.CommonUtil</function-class>    
        <function-signature>java.lang.String decoder(java.lang.String,java.lang.String)</function-signature>  
        <example>${custom.decoder('','')}</example>  
      </function>  
</taglib>  

? ?编写jsp页面，需要在头部指明引用的tld标签。?

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<%@ taglib prefix="custom" uri="/customFunction" %>  
${custom:encoder(username,'UTF-8')}  

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