java.lang.NoClassDefFoundError: javax/el/ELException

在maven中配置以下依賴：

       <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

在resin-3.0.28中運行，報以下錯誤：

Servlet.service() for servlet jsp threw exception
java.lang.NoClassDefFoundError: javax/el/ELException

原因是容器不支援JSTL1.2，換成以下依賴就好了：

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.1.2</version>
        </dependency>

 

Tomcat中也有同樣的問題

Tomcat6   JSP2.1 / Servlet2.5 / JSTL2.0

Tomcat5   JSP2.0 / Servlet2.4 / JSTL1.1

Tomcat4   JSP1.2 / Servlet2.3 / JSTL1.0

resin-3.0.28 JSP2.0 / Servlet2.4 / JSTL1.1

 

 

Tomcat5與Tomcat6的EL衝突，JSTL的版本問題
Servlet.service() for servlet jsp threw exception
java.lang.NoClassDefFoundError: javax/el/ELException
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2365)
at java.lang.Class.getDeclaredMethods(Class.java:1763)
at java.beans.Introspector$1.run(Introspector.java:1259)
at java.security.AccessController.doPrivileged(Native Method)
at java.beans.Introspector.getPublicDeclaredMethods(Introspector.java:1257)
at java.beans.Introspector.getTargetMethodInfo(Introspector.java:1125)
at java.beans.Introspector.getBeanInfo(Introspector.java:383)
at java.beans.Introspector.getBeanInfo(Introspector.java:155)
at java.beans.Introspector.getBeanInfo(Introspector.java:216)
at java.beans.Introspector.<init>(Introspector.java:364)
at java.beans.Introspector.getBeanInfo(Introspector.java:155)
at org.apache.jasper.compiler.Generator$TagHandlerInfo.<init>(Generator.java:3673)
at org.apache.jasper.compiler.Generator$GenerateVisitor.getTagHandlerInfo(Generator.java:2092)
at org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1573)
at org.apache.jasper.compiler.Node$CustomTag.accept(Node.java:1441)
at org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
at org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2213)
at org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2219)

這個問題應該是出在JSTL的支援上，通過查看，原來系統使用了JSTL1.2。

 

JSTL1.2

The JSTL 1.2 Maintenace Release aligns with the Unified Expression Language (EL) that is being delivered as part of the JavaServer Pages (JSP) 2.1 specification。JSTL 1.2 is part of the Java EE 5 platform. （from http://java.sun.com/products/jsp/jstl/）

 

JSTL1.1

Jakarta Taglibs hosts the Standard Taglib 1.1, an implementation of the JSP Standard Tag Library (JSTL), version 1.1, which was developed under the Java Community Process.
NOTE: Standard-1.1 (JSTL 1.1) requires a JSP container that supports the Java Servlet 2.4 and JavaServer Pages 2.0 specifications. Jakarta Tomcat 5 supports the new specifications. The Standard-1.1 taglib has been tested with Tomcat 5.0.3.

 

JSTL1.0
Standard-1.0 (implementation of the JSTL 1.0 specification) requires a JSP container that supports the Java Servlet 2.3 and JavaServer Pages 1.2 specifications. Jakarta Tomcat 4 supports these specifications. The Standard 1.0 taglib has been tested with Tomcat 4.1.24. (from http://jakarta.apache.org/taglibs/doc/standard-doc/intro.html)

 

Tomcat6 實現了servlet 2.5 和JSP2.1的規範，可以支援JSTL1.2；

而Tomcat5實現了 servlet 2.4 和JSP2.0的規範，只能支援JSTL1.1

所以，只要使用JSTL1.1(standard-1.1.jar和jstl-1.1.jar)替換JSTL1.2（jstl-1.2.jar）即可在Tomcat5下正常運行！

另外，web.xml必須指定使用servlet 2.4 和JSP2.0的規範：
<web-app version="2.4" 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-app_2_4.xsd">