Spring Expression Language (SpEL)

SpEL

SpEL is an Expression Language that wire the values into beans properties using expression at runtime.

Features

• Literal expressions :-
  Integer Number :-
  <property name="num" value="#{5}">  The #{} markers are a clue to Spring that the content that they contain is a SpEL expression.
  
  Floating-point numbers :-
  <property name="num" value="#{50.5}"/>
  
  Scientific notation :-
  <property name="num" value="#{2e5}"/>
  
  String :-
  <property name='str' value='#{"laptop"}'/>
• Boolean :- 
  <property name="val" value="#{true}"/>
  <property name="val" value="#{false}"/>
• Referencing Beans :-
  <property name="name" value="#{Employee}"/>
  This is same as :-
  <property name="name" ref="Employee"/>
  
  Referring another bean property :-
  <bean id="cars" class="com.proj.vehicleApp.Cars"> 
       <property name="speed" value="#{bike.speed}" />
  </bean>
  Call Method :-
  <bean id="cars" class="com.proj.vehicleApp.Cars">   
      <property name="speed" value="#{bike.getSpeed()}" /></bean>
• Arithmetic   +, -, *, /, %, ^
• Relational   <, >, ==, <=, >=, lt, gt, eq, le, ge
• Logical and, or, not, |
• Conditional ?: (ternary), ?: (Elvis)
• Regular expression matches