java/w8/GenericReflectionDemo.java

import java.lang.reflect.*;
import java.util.*;

public class GenericReflectionDemo {
    private Map<String, List<Integer>> complexField;

    public List<Double> process(Map<String, ? extends Number> map, int value) {
        return new ArrayList<>();
    }

    public static void main(String[] args) throws NoSuchFieldException, NoSuchMethodException {
        Field field = GenericReflectionDemo.class.getDeclaredField("complexField");
        Type genericType = field.getGenericType();
        System.out.println("===== 字段泛型信息 =====");
        if (genericType instanceof ParameterizedType) {
            ParameterizedType pt = (ParameterizedType) genericType;
            System.out.println("原始类型: " + pt.getRawType());
            System.out.println("键的类型: " + pt.getActualTypeArguments()[0]);
            System.out.println("值的类型: " + pt.getActualTypeArguments()[1]);
        }

        Method method = GenericReflectionDemo.class.getDeclaredMethod("process", Map.class, int.class);
        Type returnType = method.getGenericReturnType();
        System.out.println("\n===== 方法返回类型泛型 =====");
        System.out.println("返回类型: " + returnType);

        Type[] paramTypes = method.getGenericParameterTypes();
        System.out.println("\n===== 方法参数泛型 =====");
        for (Type param : paramTypes) {
            System.out.println("参数类型: " + param);
            if (param instanceof ParameterizedType) {
                ParameterizedType ppt = (ParameterizedType) param;
                System.out.println("   -> 实际类型参数: " + Arrays.toString(ppt.getActualTypeArguments()));
            }
        }
    }
}