利用反射获取泛型

Posted 2021-12-20 geekdc

package com.duchong.aar.reflect.T;

import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.List;
import java.util.Map;

public class DemoT 

    public void test01(Map<String,Integer> map, List<String> list)
        System.out.println("DemoT.test01()");
    

    public Map<Integer,String> test02()
        System.out.println("DemoT.test02()");
        return null;
    

    public static void main(String[] args) 

        try 

            //获得指定方法参数泛型信息
            Method m = DemoT.class.getMethod("test01", Map.class,List.class);
            Type[] t = m.getGenericParameterTypes();
            for (Type paramType : t) 
                System.out.println("#"+paramType);
                if(paramType instanceof ParameterizedType)
                    Type[] genericTypes = ((ParameterizedType) paramType).getActualTypeArguments();
                    for (Type genericType : genericTypes) 
                        System.out.println("泛型类型："+genericType);
                    
                
            

            //获得指定方法返回值泛型信息
            Method m2 = DemoT.class.getMethod("test02", null);
            Type returnType = m2.getGenericReturnType();
            if(returnType instanceof ParameterizedType)
                    Type[] genericTypes = ((ParameterizedType) returnType).getActualTypeArguments();

                    for (Type genericType : genericTypes) 
                        System.out.println("返回值，泛型类型："+genericType);
                    

            


         catch (Exception e) 
            e.printStackTrace();