This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Framework 6.2.0!spring-doc.cn

Literal Expressions

SpEL supports the following types of literal expressions.spring-doc.cn

String

Strings can be delimited by single quotation marks (') or double quotation marks ("). To include a single quotation mark within a string literal enclosed in single quotation marks, use two adjacent single quotation mark characters. Similarly, to include a double quotation mark within a string literal enclosed in double quotation marks, use two adjacent double quotation mark characters.spring-doc.cn

Number

Numbers support the use of the negative sign, exponential notation, and decimal points.spring-doc.cn

Integer: int or longspring-doc.cn
Hexadecimal: int or longspring-doc.cn
Real: float or doublespring-doc.cn
- By default, real numbers are parsed using Double.parseDouble().spring-doc.cn

Boolean

true or falsespring-doc.cn

Null

nullspring-doc.cn

Due to the design and implementation of the Spring Expression Language, literal numbers are always stored internally as positive numbers.spring-doc.cn

For example, -2 is stored internally as a positive 2 which is then negated while evaluating the expression (by calculating the value of 0 - 2).spring-doc.cn

This means that it is not possible to represent a negative literal number equal to the minimum value of that type of number in Java. For example, the minimum supported value for an int in Java is Integer.MIN_VALUE which has a value of -2147483648. However, if you include -2147483648 in a SpEL expression, an exception will be thrown informing you that the value 2147483648 cannot be parsed as an int (because it exceeds the value of Integer.MAX_VALUE which is 2147483647).spring-doc.cn

If you need to use the minimum value for a particular type of number within a SpEL expression, you can either reference the MIN_VALUE constant for the respective wrapper type (such as Integer.MIN_VALUE, Long.MIN_VALUE, etc.) or calculate the minimum value. For example, to use the minimum integer value:spring-doc.cn

T(Integer).MIN_VALUE — requires a StandardEvaluationContextspring-doc.cn
-2^31 — can be used with any type of EvaluationContextspring-doc.cn

The following listing shows simple usage of literals. Typically, they are not used in isolation like this but, rather, as part of a more complex expression — for example, using a literal on one side of a logical comparison operator or as an argument to a method.spring-doc.cn

Javaspring-doc.cn
Kotlinspring-doc.cn

ExpressionParser parser = new SpelExpressionParser();

// evaluates to "Hello World"
String helloWorld = (String) parser.parseExpression("'Hello World'").getValue();

// evaluates to "Tony's Pizza"
String pizzaParlor = (String) parser.parseExpression("'Tony''s Pizza'").getValue();

double avogadrosNumber = (Double) parser.parseExpression("6.0221415E+23").getValue();

// evaluates to 2147483647
int maxValue = (Integer) parser.parseExpression("0x7FFFFFFF").getValue();

boolean trueValue = (Boolean) parser.parseExpression("true").getValue();

Object nullValue = parser.parseExpression("null").getValue();

val parser = SpelExpressionParser()

// evaluates to "Hello World"
val helloWorld = parser.parseExpression("'Hello World'").value as String

// evaluates to "Tony's Pizza"
val pizzaParlor = parser.parseExpression("'Tony''s Pizza'").value as String

val avogadrosNumber = parser.parseExpression("6.0221415E+23").value as Double

// evaluates to 2147483647
val maxValue = parser.parseExpression("0x7FFFFFFF").value as Int

val trueValue = parser.parseExpression("true").value as Boolean

val nullValue = parser.parseExpression("null").value