BE THE CODER > Spring > Expression Language

The Spring Expression Language (SpEL) is a simple and powerful expression language which helps to query and manipulate objects at runtime. The following example shows using evaluation context. It provides a namespace for accessing variables.

File Name :	com/bethecoder/tutorials/spring3/tests/spel/EvaluationContextTest.java
Author :	Sudhakar KV
Email :	[email protected]


package com.bethecoder.tutorials.spring3.tests.spel;



import org.springframework.expression.Expression;

import org.springframework.expression.ExpressionParser;

import org.springframework.expression.spel.standard.SpelExpressionParser;

import org.springframework.expression.spel.support.StandardEvaluationContext;



import com.bethecoder.tutorials.spring3.basic.Employee;



public class EvaluationContextTest {



  /**

   * @param args

   */

  public static void main(String[] args) {



    Employee emp = new Employee(1, "BTC");

    StandardEvaluationContext stdContext = new StandardEvaluationContext(emp);

    

    ExpressionParser parser = new SpelExpressionParser();

    Expression exp = parser.parseExpression("name");

    String value = exp.getValue(stdContext, String.class); //emp.getName()

    System.out.println(value);



    exp = parser.parseExpression("name == 'BTC'");

    boolean result = exp.getValue(stdContext, Boolean.class); 

    System.out.println(result);

    

    

    Employee emp2 = new Employee(2, "ABC");

    exp = parser.parseExpression("name");  //emp2.getName()

    value = exp.getValue(emp2, String.class); //creates default evaluation context internally

    System.out.println(value);

  }



}

Evaluation Context