UserRepository文件

package com.study.repository;

import com.study.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.repository.NoRepositoryBean;

@NoRepositoryBean
public interface UserRepository extends JpaRepository {
    User findById(long id);

    Long deleteById(long id);
}

添加@NoRepositoryBean注解，必须使用该注解标明，此接口不是一个Repository Bean 否则就会报上方的错误

把@NoRepositoryBean注释掉后，应把它变成一个Repository Bean

UserRepository extends JpaRepository<User,Long>

package com.study.repository;

import com.study.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;

//@NoRepositoryBean
public interface UserRepository extends JpaRepository<User,Long> {
    User findById(long id);

    Long deleteById(long id);
}