Java determines whether a class is a subclass or parent class of a certain class

Class c = ArrayList.class;
c.isPrimitive(); //判断c是否为基本数据类型
c.isAssignableFrom(List.class);  //判断c是否是List类的子类或父类
c.getGenericType(); //得到泛型类型

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Example: Obtaining the generic type in the List8742468051c85b06f0a0af9e3e506b5c collection through reflection

package com.zf.target;
 
import java.lang.reflect.Field;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.List;
import java.util.Map;
 
class T{
    List<A>  a;
    List<B>  b;
//    List l ;
    Map<Integer, String> map ;
    int c;
}
 
class A {}
class B{}
 
public class Test9{
 
    public static void main(String[] args) {
        Class tc = T.class;
        Field[] fields = tc.getDeclaredFields();
        for (Field f : fields) {
            Class fc = f.getType();
            if(fc.isPrimitive()){
                System.out.println("基本数据类型： " + f.getName() + "  " + fc.getName());
            }else{
                if(fc.isAssignableFrom(List.class)){ //判断是否为List
                    System.out.println("List类型：" + f.getName());
                    Type gt = f.getGenericType();    //得到泛型类型
                    ParameterizedType pt = (ParameterizedType)gt;
                    Class lll = (Class)pt.getActualTypeArguments()[0];
                    System.out.println("\t\t" + lll.getName());
                }
            }
        }
    }
    
}

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