Spring Tutorials

We can use many operators in SpEL such as arithmetic, relational, logical etc. There are given a lot of examples of using different operators in SpEL as given below.

Relational operators

The relational operators; equal, not equal, less than, less than or equal, greater than, and greater than or equal are supported using standard operator notation. the syntax used in SpEl as given below.

//evaluates to true
boolean trueValue = parser.parseExpression("3 == 3")
.getValue(Boolean.class);

//evaluates to false
boolean falseValue = parser.parseExpression("2 < -1.0")
.getValue(Boolean.class);

//evaluates to true
boolean trueValue = parser.parseExpression("'bay' < 'boy'")
.getValue(Boolean.class);

Logical operators

The logical operators that are supported are and, or, and not. the syntax used in SpEl as given below.

/-- AND --
//evaluates to false
boolean falseValue = parser.parseExpression("true and false")
.getValue(Boolean.class);

//evaluates to true
String expression = "isMember('John Smith') and isMember('Employee')";
boolean trueValue = parser.parseExpression(expression)
.getValue(societyContext, Boolean.class);

//-- OR --
//evaluates to true
boolean trueValue = parser.parseExpression("true or false")
.getValue(Boolean.class);

//evaluates to true
String expression = "isMember('John Smith') or isMember('Social Service')";
boolean trueValue = parser.parseExpression(expression)
.getValue(societyContext, Boolean.class);

//-- NOT --
//evaluates to false
boolean falseValue = parser.parseExpression("!true")
.getValue(Boolean.class);

//-- AND and NOT --
String expression = "isMember('John Smith') and !isMember('Employee')";
boolean falseValue = parser.parseExpression(expression)
.getValue(societyContext, Boolean.class);

Mathematical operators

The addition operator can be used on both numbers and strings. Subtraction, multiplication and division can be used only on numbers. Other mathematical operators supported are modulus (%) and exponential power (^).

//Addition
int num = parser.parseExpression("5 + 1")
.getValue(Integer.class); // 6

// hello spring
String testString = parser.parseExpression
("'hello' + ' ' + 'spring'").getValue(String.class); 

//Subtraction
int num = parser.parseExpression("2 - -3")
.getValue(Integer.class); // 5

double d = parser.parseExpression("1000.00 - 1e4")
.getValue(Double.class); // -9000

//Multiplication
int num = parser.parseExpression("-3 * -3")
.getValue(Integer.class); // 9

double num = parser.parseExpression("2.0 * 3e0 * 4")
.getValue(Double.class); // 24.0

//Division
int num = parser.parseExpression("6 /2")
.getValue(Integer.class); // 3

double num = parser.parseExpression("8.0 / 4e0 / 2")
.getValue(Double.class); // 1.0

//Modulus
int num = parser.parseExpression("7 % 2")
.getValue(Integer.class); // 1

int num = parser.parseExpression("8 / 5 % 2")
.getValue(Integer.class); // 1

//Operator precedence
int num = parser.parseExpression("1+2-3*4")
.getValue(Integer.class); // -9

Example of all Operator in SpEL

import org.springframework.expression.ExpressionParser;  
import org.springframework.expression.spel.standard.SpelExpressionParser;  
    
public class Simple {  
public static void main(String[] args) {  
ExpressionParser parser = new SpelExpressionParser();  
  
//arithmetic operator  
System.out.println(parser.parseExpression("'Hello'+'?'").getValue());  
System.out.println(parser.parseExpression("15 * 20/2").getValue());  
System.out.println(parser.parseExpression
("'Today is: '+ new java.util.Date()").getValue());
  
//logical operator  
System.out.println(parser.parseExpression("true and false").getValue());  
  
//Relational operator  
System.out.println(parser.parseExpression("'john'.length()==4").getValue());  
}  
}