This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Framework 6.1.8!

Inline Maps

You can also directly express maps in an expression by using {key:value} notation. The following example shows how to do so:

  • Java

  • Kotlin

// evaluates to a Java map containing the two entries
Map inventorInfo = (Map) parser.parseExpression("{name:'Nikola',dob:'10-July-1856'}").getValue(context);

Map mapOfMaps = (Map) parser.parseExpression("{name:{first:'Nikola',last:'Tesla'},dob:{day:10,month:'July',year:1856}}").getValue(context);
// evaluates to a Java map containing the two entries
val inventorInfo = parser.parseExpression("{name:'Nikola',dob:'10-July-1856'}").getValue(context) as Map<*, *>

val mapOfMaps = parser.parseExpression("{name:{first:'Nikola',last:'Tesla'},dob:{day:10,month:'July',year:1856}}").getValue(context) as Map<*, *>

{:} by itself means an empty map. For performance reasons, if the map is itself composed of fixed literals or other nested constant structures (lists or maps), a constant map is created to represent the expression (rather than building a new map on each evaluation). Quoting of the map keys is optional (unless the key contains a period (.)). The examples above do not use quoted keys.