JAVA 反射 (5)：数组和泛型数组

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java.lang.Class

public native Class<?> getComponentType()返回表示数组组件类型的 Class

System.out.println(String.class.getComponentType()); 返回nullSystem.out.println(String[].class.getComponentType());  返回java.lang.StringSystem.out.println(String[][].class.getComponentType()); 返回[Ljava.lang.String;

java.lang.reflect.GenericArrayType

Type getGenericComponentType();返回表示泛型数组组件类型的Type

public class Test {    public static void main(String[] args) throws NoSuchMethodException {        Class testClass = Test.class;        Method method = testClass.getMethod("test", ArrayList[][].class);        Type[] types = method.getGenericParameterTypes();        for (Type type : types) {            if (type instanceof GenericArrayType) {                System.out.println("GenericArrayType1 : " + type.toString());                GenericArrayType genericArrayType = (GenericArrayType) type;                Type getype = genericArrayType.getGenericComponentType();                System.out.println("GenericArrayType2 : " + getype.toString());                if (getype instanceof GenericArrayType) {                    GenericArrayType genericArrayType2 = (GenericArrayType) getype;                    Type getype2 = genericArrayType2.getGenericComponentType();                    System.out.println(getype2.toString());                    if (getype2 instanceof Class) {                        System.out.println("Class");                    } else if (getype2 instanceof ParameterizedType) {                        System.out.println("ParameterizedType");                    } else if (getype2 instanceof GenericArrayType) {                        System.out.println("GenericArrayType3");                    }                }            } else if (type instanceof ParameterizedType) {                System.out.println("ParameterizedType");            } else if (type instanceof Class) {                System.out.println("class");            }        }    }    public static void test(ArrayList<String>[][] as) {    }}输出结果：GenericArrayType1 : java.util.ArrayList<java.lang.String>[][]GenericArrayType2 : java.util.ArrayList<java.lang.String>[]java.util.ArrayList<java.lang.String>ParameterizedType将test方法的参数类型改为ArrayList[][] 输出结果为：class

总结：这两个方法用来一级一级脱去数组的维数，getComponentType用来处理普通类型数组
getGenericComponentType用来处理泛型数组

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