[groovy] closure (closure call | closure default parameter it | code example)

One 、 Call closure

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perform Closure Variable Of call() Method , You can call the closure ;

        //  Define closure variables         def closure = { 
                println "Hello Closure!"        }        //  Call closure         closure.call()

Execute the above code , Print Hello Closure! ;

direct stay Closure After a variable , Write a bracket , You can also call closures ;

        //  Define closure variables         def closure = { 
                println "Hello Closure!"        }                //  Call closure         closure()

Execute the above code , Print Hello Closure! ;

Two 、 Closure default parameters it

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Closure Closure Default OK Receive a default parameter , The parameter variable name is it ,

• If No parameter passed in , Then it for null ,
• If Pass in the parameter , The it Variable is the parameter value that should be passed in ;

stay closure() Invocation time , Pass in a parameter , It will be automatically assigned to it Variable ;

        //  Define closure variables         def closure = { 
                println it        }        //  Call closure  ,  And pass in a default parameter         closure("Hello")

The above code will print Hello ;

3、 ... and 、 Code example

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Code example :

class Test { 
        static void main(args) { 
            //  Define closure variables         def closure = { 
                println "Hello Closure!"        }                // I.  Print closure type                         //  Print closure variable types         println closure.getClass()                // II.  Call closure                         //  Call closure  1        closure.call()        //  Call closure  2        closure()                // III.  Closure default parameters                         //  Define closure variables         def closure1 = { 
                println it        }        //  Call closure         closure1.call("Hello")        //  Call closure  ,  And pass in a default parameter         closure1("Closure")    }}

Execution results :

class Test$_main_closure1Hello Closure!Hello Closure!HelloClosure