为什么EL表达式在java中无法解析JSP

为什么EL表达式在java中无法解析jsP？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。

收集了如下版本：

WEB-app_2_2.xsd  <&#63;xml version="1.0" encoding="UTF-8"&#63;>   <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" "Http://java.sun.com/dtd/web-app_2_2.dtd">    <&#63;xml version="1.0" encoding="UTF-8"&#63;> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" "http://java.sun.com/dtd/web-app_2_2.dtd">   web-app_2_3.xsd  <&#63;xml version="1.0" encoding="UTF-8"&#63;>   <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">    <&#63;xml version="1.0" encoding="UTF-8"&#63;> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">   web-app_2_4.xsd  <&#63;xml version="1.0" encoding="UTF-8"&#63;>   <web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.4" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee  http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">    <&#63;xml version="1.0" encoding="UTF-8"&#63;> <web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.4" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee  http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">   web-app_2_5.xsd  <&#63;xml version="1.0" encoding="UTF-8"&#63;>   <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.5" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">    <&#63;xml version="1.0" encoding="UTF-8"&#63;> <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.5" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">