在Groovy中反思的屬性註釋

Question

是否有一種方便的方式來迭代Object的屬性並檢查每個對象的註釋？

Answer 1

你可以這樣來做：

// First, declare your annotation 
import java.lang.annotation.* 

@Retention(RetentionPolicy.RUNTIME) 
@Target(ElementType.FIELD) 
public @interface MyAnnot { 
} 

// Then, define your class with it's annotated Fields 
class MyClass { 
    @MyAnnot String fielda 
    String fieldb 
    @MyAnnot String fieldc 
} 

// Then, we will write a method to take an object and an annotation class 
// And we will return all properties of the object that define that annotation 
def findAllPropertiesForClassWithAnotation(obj, annotClass) { 
    obj.properties.findAll { prop -> 
    obj.getClass().declaredFields.find { 
     it.name == prop.key && annotClass in it.declaredAnnotations*.annotationType() 
    } 
    } 
} 

// Then, define an instance of our class 
MyClass a = new MyClass(fielda:'tim', fieldb:'yates', fieldc:'stackoverflow') 

// And print the results of calling our method 
println findAllPropertiesForClassWithAnotation(a, MyAnnot) 

在這種情況下，這個打印出：

[fielda:tim, fieldc:stackoverflow] 

希望它能幫助！