jsf - Using EL 2.2 with Tomcat 6.0.24

Question

With JSF 2 you should be able to do this:

<h:commandButton action="#{myBean.myAction(myParameter)}"/>

which would then call the action method, passing in the parameter (assume it's an Integer):

@ManagedBean
@SessionScoped
public class MyBean {
    ...
    public String myAction(Integer myParameter) {
        // do something
        return null;
    }
    ...
}

This works on Glassfish v3 perfectly. However not on Tomcat, you get an ELException notifying of the parse error

Caused by: javax.el.ELException: Error Parsing: ...

Now, there's a documented way of making this work using EL 2.2 and Glassfish's implementation by replacing the el-api jar in the Tomcat lib directory, however I still get the same error occurring with no luck. Tomcat's really starting to frustrate me! JSF2 is meant to be easier!

Maven POM fragments:

<repositories>
  <repository>
    <id>sun</id>
    <url>http://download.java.net/maven/2/</url>
  </repository>
  <repository>
    <id>jboss</id>
    <url>http://repository.jboss.com/maven2/</url>
  </repository>
</repositories>
...
  <dependency>
    <groupId>javax.el</groupId>
    <artifactId>el-api</artifactId>
    <version>2.2</version>
    <scope>provided</scope>
  </dependency>

  <dependency>
    <groupId>org.glassfish.web</groupId>
    <artifactId>el-impl</artifactId>
    <version>2.2</version>
    <scope>provided</scope>
  </dependency>

---

More info.

Here's part of the stack trace, seems it's still using an Apache EL implementation, and not the one I dumped into lib. I completely removed the existing el-api.jar that came with Tomcat, is there an el-impl.jar I'm meant to remove somewhere too that may be overriding something?

Was expecting one of:
    "}" ...
    "." ...
    "[" ...
    ">" ...
    "gt" ...
    "<" ...
    "lt" ...
    ">=" ...
    "ge" ...
    "<=" ...
    "le" ...
    "==" ...
    "eq" ...
    "!=" ...
    "ne" ...
    "&&" ...
    "and" ...
    "||" ...
    "or" ...
    "*" ...
    "+" ...
    "-" ...
    "/" ...
    "div" ...
    "%" ...
    "mod" ...

    at org.apache.el.parser.ELParser.generateParseException(ELParser.java:2142)
    at org.apache.el.parser.ELParser.jj_consume_token(ELParser.java:2024)
    at org.apache.el.parser.ELParser.DeferredExpression(ELParser.java:113)
    at org.apache.el.parser.ELParser.CompositeExpression(ELParser.java:40)
    at org.apache.el.lang.ExpressionBuilder.createNodeInternal(ExpressionBuilder.java:93)
    ... 64 more

Answer 1

As mentioned in other answers, you need to add the el-api-2.2.jar to your Tomcat server's lib folder, and the el-impl-2.2.jar to your WEB-INF/lib folder.

Other answers mention deleting jasper or creating custom implementations of ExpressionFactoryImpl. That might work, but you shouldn't need to do that.

You just need to override the expression factory implementation using org.apache.myfaces.EXPRESSION_FACTORY on MyFaces or com.sun.faces.expressionFactory on Mojarra.

<context-param>
    <param-name>org.apache.myfaces.EXPRESSION_FACTORY</param-name>
    <param-value>com.sun.el.ExpressionFactoryImpl</param-value>
</context-param>
  <context-param>
    <param-name>com.sun.faces.expressionFactory</param-name>
    <param-value>com.sun.el.ExpressionFactoryImpl</param-value>
  </context-param>