Spring Class_04.2020_CORE_SpEL

Question 1

What is SpEL?

Answer 1

Spring expression language

Question 2

What can SpEL expression can be used for?

Answer 2

defining BeanDefinitions

Question 3

What is syntax to define SpEL expression?

Answer 3

#{} 
${spring.version}  (in maven)

Question 4

Bean reference using SpEL

Answer 4

@Value(«#{countryBean}»)
private Country country;

(используется id из application-context.xml)

Question 5

Method invocation using SpEL

Answer 5

Value = «#{countryBean.toString()}»

Question 6

Operators using SpEL

Answer 6

Name = «equalTest» Value = «#{countryBean == 100}»

return boolean and set it in field with name «equalTest»

Question 7

How to use regex with spell?

Answer 7

use word ‘matches’

#{(‘100’ matches ‘\d+’)}

Question 8

What does ExpressionParser do?

Answer 8

allows to get value of bean fields

Question 9

What is the context used by ExpressionParser?

Answer 9

SEC

StandarsEvaluationContext

Question 10

What is used as parameter for parseExpresion() method?

Answer 10

name of field

Question 11

What is used as parameter for getValue() method of ExcpressionParser?

Answer 11

instance of SEC (StandarsEvaluationContext) and type of field (ex. String.class)

Question 12

Example of expression parser using

Answer 12

Bank bank = new Bank(«Alfa bank»); StandarsEvaluationContext bankContext = new StandarsEvaluationContext(bank); 
String bankName = parser.parseExpression(«name»).getValue(bankContext, String.class);