A characteristic .SPEL
1. references bean bean name;
2. access object properties and invoke methods;
3. calculating the value by the line;
4. Regular expression matching;
The set of operations;
II. Expressions and attributes thereof placeholder
1. First manifestation expression # {}, {# 1} example, this expression is a simple body removed numeric constant, $ {} is the placeholder properties.
III. Various examples
1 may represent a floating point literals, String Boolean value and the value of
# {3.14159}
# { 'Hello World'}
# {} to false
2. references bean, properties and methods
# {the beanName}
# {the beanName. } propertise
# beanName.method {()}
3. types used in expression
# {T (java.lang.Math) .PI}
4.SPEL operator
can use the arithmetic comparison logic conditions regex
