Using EL 2.2 with Tomcat 6.0.24

问题

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

回答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>

回答2:

As I mentioned in a comment, this can be solved by upgrading the EL implementation (i.e. replacing jasper-el.jar with el-impl-2.2.jar)

回答3:

You can use JBoss EL.

It's an implementation of Expression Language 2.1. But it has extensions to allow method parameters as in your example:

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

The advantage is that you only have to change your webapp and not Tomcat's lib directory.

Instructions

Download the latest version of Seam 2
Extract lib/jboss-el.jar
Copy it to WEB-INF/lib/jboss-el.jar

In your web.xml set:

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

See also Invoke direct methods or methods with parameters in EL.

回答4:

Replacing el-api.jar and el-impl.jar with el-api-2.2.jar and el-impl-2.2.jar solve the problem.

Also you need to add in your context.xml the context parameter

<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>

来源：https://stackoverflow.com/questions/2333605/using-el-2-2-with-tomcat-6-0-24

标签

jsf

parameters

action

tomcat6