SpEL Operators

In this tutorial, we will explain how Spring Expression Language(SpEL) allows us to use different kinds of operators to form its expressions. These operators are -

Arithmetic Operators

Logical Operators

Relational Operators

Type Operator

Ternary Operator

instanceOf Operator

Let's see how each of these operators are used to form expressions in Spring Expression Language(SpEL) by coding examples.

Adding JARs

Before we explain how different operators are used within expressions of Spring Expression Language(SpEL) in a Java project, we are going to some JARs files to that project. These JARs are required in order to successfully execute a Spring project containing Spring Expression Language(SpEL).

All these JARs are included in the folder named libs(within our Spring installation folder). So, we need to add all the JARs in the libs folder to our build path of our Java project.

Note : Those who don't know how to add JARs to the build path of your Java project in Eclipse IDE, please refer to our section Adding JARs to your Spring project in Eclipse.

Arithmetic Operators in Spring Expression Language(SpEL)

+ operator(addition)
- operator(subtraction)
* operator(multiplication)
/ operator(division)
% operator(modulus)

Example

package decodejava;

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

public class Utility {

	public static void main(String[] args) 
	{
		SpelExpressionParser parser = new SpelExpressionParser();
		
		//Arithmetic operators + - / % with SpEL
		System.out.println(parser.parseRaw("'Tho' + 'mas'").getValue());
		System.out.println(parser.parseRaw("12 * 4").getValue());
		System.out.println(parser.parseRaw("100 - 50").getValue());
		System.out.println(parser.parseRaw("10 / 2").getValue());
		System.out.println(parser.parseRaw("100 % 10").getValue());	
	}
}

Output

Thomas
48
50
5
0

Logical Operators in Spring Expression Language(SpEL)

&& operator with and
|| operator with or
! operator with not

Example

package decodejava;

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

public class Utility {

	public static void main(String[] args) 
	{
		SpelExpressionParser parser = new SpelExpressionParser();
		
		//Logical operators and(&&) or(||) not(!) with SpEL
		System.out.println("true && true : " + parser.parseRaw("true and true").getValue());
		System.out.println("true && false : " + parser.parseRaw("true && false").getValue());
		System.out.println("false && false : " + parser.parseRaw("false and false").getValue());
		System.out.println("true || false : " + parser.parseRaw("true or false").getValue());
		System.out.println("true || true : " + parser.parseRaw("true || true").getValue());
		System.out.println("false || false : " + parser.parseRaw("false or false").getValue());
		System.out.println("! false : " + parser.parseRaw("! false").getValue());
		System.out.println("! true : " + parser.parseRaw("not true").getValue());
	}
}

Output

true && true : true
true && false : false
false && false : false
true || false : true
true || true : true
false || false : false
! false : true
! true : false

Relational Operators in Spring Expression Language(SpEL)

<(less than operator)
>(greater than operator)
<=(less than equals to operator)
>=(greater than equals to operator)
==(equals to operator)
!=(not equals to operator)

Example

package decodejava;

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

public class Utility {

	public static void main(String[] args) 
	{
		SpelExpressionParser parser = new SpelExpressionParser();
		
		//Relational operators >,<,>=,<=,==,!=  with SpEL
		System.out.println("100 > 50 : " + parser.parseRaw("100 > 50").getValue());
		System.out.println("200 < 100 : " + parser.parseRaw("200 < 100").getValue());
		System.out.println("10 >= 10 : " + parser.parseRaw("10 >= 10").getValue());
		System.out.println("20 <= 19 : " + parser.parseRaw("20 <= 19").getValue());
		System.out.println("9 == 9 : " + parser.parseRaw("9 == 9").getValue());
		System.out.println("Thomas == Thomas : " + parser.parseRaw("'Thomas' == 'Thomas'").getValue());
		System.out.println("true != false : " + parser.parseRaw("true != false").getValue());
		System.out.println("99 != 99.9 : " + parser.parseRaw("99 != 99.9").getValue());
	}
}

Output

100 > 50 : true
200 < 100 : false
10 >= 10 : true
20 <= 19 : false
9 == 9 : true
Thomas == Thomas : true
true != false : true
99 != 99.9 : true

Ternary, Type and instanceOf operators in SpEL

expressions

Conditional operator - Conditional operator is also called ternary operator. For those who are not aware of conditional operator, please read Java Conditional Operator.
Type operator- Spring Expression Language(SpEL) provides us an operator called Type operator. This operator allows us to specify a Java reference type i.e. Java class and access its static methods.Type operator can be used as T(type), where type refers to a Java class.
instanceOf operator - The instanceof operator is used to know whether an object(pointed by a reference variable) is of a particular type or not. For those who are not aware of instanceOf operator, please read Java instanceOf Operator.

Example

package decodejava;

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

public class Utility {

	public static void main(String[] args) 
	{
		SpelExpressionParser parser = new SpelExpressionParser();
		
		//Ternary operator ?:  with SpEL
		System.out.println("100 > 50 : " + parser.parseRaw("100 > 50 ? true:false").getValue());
		System.out.println("200 < 100 : " + parser.parseRaw("200 < 100 ? true:false").getValue());
		System.out.println("100 == 99.9 : " + parser.parseRaw("100 == 100 ? true:false").getValue());
		System.out.println("Adam == Adam : " + parser.parseRaw("'Adam' == 'Adam' ? true:false").getValue());
		System.out.println("Moon == Moons : " + parser.parseRaw("'Moon' == 'Moons' ? true:false").getValue());
		
		
		//Type operator used to invoke static methods of references type String and Wrapper Classes
		System.out.println(parser.parseRaw("T(String).valueOf(10)").getValue());
		System.out.println(parser.parseRaw("T(Integer).parseInt(1001,2)").getValue());
		System.out.println(parser.parseRaw("T(Double).parseDouble('99.9')").getValue());
		System.out.println("Minimum value between 99.2 and 99.9 : " + parser.parseRaw("T(Math).min(99.2, 99.9)").getValue());
		System.out.println("Maximum value between 99.2 and 99.9 : " + parser.parseRaw("T(Math).max(99.2, 99.9)").getValue());

		
		//instanceOf operator
		System.out.println("Is Hello an instance of String : " + parser.parseRaw("'Hello' instanceOf T(String)").getValue());
		System.out.println("Does new String() creates an Instance of String : " + parser.parseRaw("new String() instanceOf T(String)").getValue());
		System.out.println("Is 10 an object of Integer : " + parser.parseRaw("10 instanceOf T(Integer)").getValue());
		System.out.println("Is 6.5 an object of Double : " + parser.parseRaw("6.5 instanceOf T(Float)").getValue());
		System.out.println("Is 9.9 an object of Double : " + parser.parseRaw("9.9 instanceOf T(Double)").getValue());
		
		
		
	}
}

Output

100 > 50 : true
200 < 100 : false
100 == 99.9 : true
Adam == Adam : true
Moon == Moons : false
10
9
99.9
Minimum value between 99.2 and 99.9 : 99.2
Maximum value between 99.2 and 99.9 : 99.9
Is Hello an instance of String : true
Does new String() creates an Instance of String : true
Is 10 an object of Integer : true
Is 6.5 an object of Double : false
Is 9.9 an object of Double : true

This concludes our tutorial on how Spring Expression Language(SpEL) uses different kinds of operators to form its expressions. In our next tutorial, we will explain how to access methods(static and non-static) of a class using the Spring Expression Language(SpEL).