Spring SpEL - Literal Expression

SpEL expression supports following types of literals −

• Strings − Single quote delimited strings. To use single quote, put another single quote around it.

• Numeric − int, real and hex expressions are supported.

• boolean

• null

Following example shows the various use cases.

Example - Usage of literals in SpEL

Let's update the project created in Spring SpEL - Create Project chapter. We're updating following file −

• MainApp.java − Main application to run and test.

MainApp.java

Here is the content of MainApp.java file −

package com.tutorialspoint;

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

public class MainApp {
   public static void main(String[] args) {
      ExpressionParser parser = new SpelExpressionParser();
      
      // parse a simple text
      String message = (String) parser.parseExpression("'Tutorialspoint'").getValue();
      System.out.println(message);

      // parse a double from exponential expression
      double avogadros  = (Double) parser.parseExpression("6.0221415E+23").getValue();
      System.out.println(avogadros);	

      // parse an int value from Hexadecimal expression
      int intValue = (Integer) parser.parseExpression("0x7FFFFFFF").getValue();
      System.out.println(intValue);

      // parse a boolean 
      boolean booleanValue = (Boolean) parser.parseExpression("true").getValue();
      System.out.println(booleanValue);

      // parse a null object
      Object nullValue = parser.parseExpression("null").getValue();
      System.out.println(nullValue);
   }
}

Output

Once you are done creating the source and bean configuration files, let us run the application. If everything is fine with your application, it will print the following message −

Tutorialspoint
6.0221415E23
2147483647
true
null