[SOLVED] How to evaluate EL expression in Tomcat servlet environment?

How to evaluate EL expression in Tomcat servlet environment?

How to evaluate EL expression in Tomcat servlet?

Tomcat uses Jasper EL.

https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-jasper-el

https://tomcat.apache.org/tomcat-9.0-doc/api/org/apache/jasper/el/package-summary.html

From the javadoc, it does not have ExpressionFactory impl to construct an ELContext object.

ELContext elContext = new ELContextImpl(expressionFactoryImpl);

Any examples on how to evaluate EL in Tomcat servlet?

Solution

The first link is for tomcat-jasper-el artifact which has a dependency on tomcat-el-api. This EL API can be used for evaluating EL expressions in Java servlets:

EL in Stand-alone environment EL 3.0 includes APIs for using EL in a stand-alone environment.

ELProcessor provides simple APIs for the direct evaluations of expressions. It also makes it easy to define functions, set variables, and define a beans locally.

ELManager provides a lower level APIs for managing the EL parsing and evaluation environment. It contains a default ELContext StandardELContext.

The examples you are looking is using old version of javax.el.