Class lstUClazz = List<User>.class

List<User> listUser = new ArrayList<User>();
Type genType = listUser.getClass().getClass().getGenericSuperclass();

Class templatClazz = null;

if(ParameterizedType.class.isInstance(genType)
{
  //无法获取到User类，或者可能获取到错误的类型，如果有同名且不带包名的泛型存在
  ParameterizedType parameterizedType = (ParameterizedType) genType;
 templatClazz = (Class) parameterizedType.getActualTypeArguments()[0];
}

 

public abstract class JdbcDaoSupport<T> {
   
  protected JdbcDaoSupport() {
    
  }
   public Class getTempalteType()
  {
     Class<T> clazz = (Class<T>) ((ParameterizedType) getClass()
        .getGenericSuperclass()).getActualTypeArguments()[0];
     return clazz;                    
  }
}

public class UserDao extends JdbcDaoSupport<User> {
}

public class Test{
    public static void main(String[] args)
    {
      UserDao dao = new UserDao();
      Class clazz = dao.getTemplateType();
      System.out.println(clazz.getName()); //输出 xxx.xxx.User
    }
}

public class Test extends ClassA<String> { 
  private List<String> list; 
  private Map<String, Object> map; 
 
  /*** 
   * 获取List中的泛型 
   */ 
  public static void testList() throws NoSuchFieldException, SecurityException { 
    Type t = Test.class.getDeclaredField("list").getGenericType(); 
    if (ParameterizedType.class.isAssignableFrom(t.getClass())) { 
      for (Type t1 : ((ParameterizedType) t).getActualTypeArguments()) { 
        System.out.print(t1 + ","); 
      } 
      System.out.println(); 
    } 
  } 
 
  /*** 
   * 获取Map中的泛型 
   */ 
  public static void testMap() throws NoSuchFieldException, SecurityException { 
    Type t = Test.class.getDeclaredField("map").getGenericType(); 
    if (ParameterizedType.class.isAssignableFrom(t.getClass())) { 
      for (Type t1 : ((ParameterizedType) t).getActualTypeArguments()) { 
        System.out.print(t1 + ","); 
      } 
      System.out.println(); 
    } 
  } 
 
  public static void main(String args[]) throws Exception { 
    System.out.println(">>>>>>>>>>>testList>>>>>>>>>>>"); 
    testList(); 
    System.out.println("<<<<<<<<<<<testList<<<<<<<<<<<\n"); 
    System.out.println(">>>>>>>>>>>testMap>>>>>>>>>>>"); 
    testMap(); 
    System.out.println("<<<<<<<<<<<testMap<<<<<<<<<<<\n"); 
    System.out.println(">>>>>>>>>>>testClassA>>>>>>>>>>>"); 
    new Test().testClassA(); 
    System.out.println("<<<<<<<<<<<testClassA<<<<<<<<<<<"); 
  } 
 
} 

List<User> lst = new ArrayList<User>(){};
Type genType = listUser.getClass().getClass().getGenericSuperclass();

Class templatClazz = null;

if(ParameterizedType.class.isInstance(genType)
{
  ParameterizedType parameterizedType = (ParameterizedType) genType;
 templatClazz = (Class) parameterizedType.getActualTypeArguments()[0];
}

Class clz = new ArrayList<User>(){}.getClass();

class JsonToObjectUtil {

 public static <T> T jsonToObject(Class<T> clz,List<String> jsonList){
 
 Type genType = clz.getClass().getGenericSuperclass();
 Class templatClazz = null;
 
 if(ParameterizedType.class.isInstance(genType));
 {
  ParameterizedType parameterizedType = (ParameterizedType) genType;
  templatClazz = (Class) parameterizedType.getActualTypeArguments()[0];
 }
 List<Object> lst = new ArrayList<Object>();
 /*****/
 if(templatClazz!=null && jsonList!=null)
 {
  for (String str : jsonList) {
  
  Gson gson = new Gson();
  Object fromJson = gson.fromJson(str, templatClazz);
  lst.add(fromJson);
  }
  
 }
 /*****/
 return (T) lst;
 }
 
 public static void main(String[] args) {
 
 List<String> jsonList = null;
 //略去一部分填充jsonList的逻辑
 
 Class superClazz = new ArrayList<User>(){}.getClass();
 List jsonToObject = JsonToObjectUtil.jsonToObject(superClazz, jsonList);
 
 }
 
}