findById、getOne和findOneById的区别

代码示例

@GetMapping("/getOne")
	public ResultBean getOne(Long id) {
		return ResultBean.ok(stu2Service.getOne(id));
	}

@GetMapping("/findById")
	public ResultBean findById(Long id) {
		return ResultBean.ok(stu2Service.findById(id));
	}

@GetMapping("/findOneById")
	public ResultBean findOneById(Long id) {
		return ResultBean.ok(stu2Service.findOneById(id));
	}

总结 不同点

  1. 返回对象不同 
public Optional<T> findById(ID id)；	返回的是Optional对象，通过.get()可获取到对象
public T getOne(ID id)；	不是直接返回的对象，但此方法可以获取对象的相关属性值
Stu2 findOneById(Long id);	根据命名规则中自定义实现，可直接返回到对象
  1. 对空值异常的处理不同,此处模拟的是如果Id在数据库中不存在时的异常 
findById
        	No value present] with root cause

 getOne
 	Unable to find com.aust.first.entity.Stu2 with id 20

 findOneById，没有异常出现
  1. SQL语句不同 
		findById
        	SELECT
	stu2x0_.id_ AS id_1_1_0_,
	stu2x0_.admission_time AS admissio2_1_0_,
	stu2x0_.age_ AS age_3_1_0_,
	stu2x0_.created_by AS created_4_1_0_,
	stu2x0_.hobbies_ AS hobbies_5_1_0_,
	stu2x0_.name_ AS name_6_1_0_,
	stu2x0_.phone_ AS phone_7_1_0_,
	stu2x0_.sid_ AS sid_8_1_0_,
	stu2x0_.summary_ AS summary_9_1_0_
FROM
	ls_stu2 stu2x0_
WHERE
	stu2x0_.id_ =?

 		getOne        	
SELECT
	stu2x0_.id_ AS id_1_1_0_,
	stu2x0_.admission_time AS admissio2_1_0_,
	stu2x0_.age_ AS age_3_1_0_,
	stu2x0_.created_by AS created_4_1_0_,
	stu2x0_.hobbies_ AS hobbies_5_1_0_,
	stu2x0_.name_ AS name_6_1_0_,
	stu2x0_.phone_ AS phone_7_1_0_,
	stu2x0_.sid_ AS sid_8_1_0_,
	stu2x0_.summary_ AS summary_9_1_0_
FROM
	ls_stu2 stu2x0_
WHERE
	stu2x0_.id_ =?

 		findOneById        	
SELECT
	stu2x0_.id_ AS id_1_1_,
	stu2x0_.admission_time AS admissio2_1_,
	stu2x0_.age_ AS age_3_1_,
	stu2x0_.created_by AS created_4_1_,
	stu2x0_.hobbies_ AS hobbies_5_1_,
	stu2x0_.name_ AS name_6_1_,
	stu2x0_.phone_ AS phone_7_1_,
	stu2x0_.sid_ AS sid_8_1_,
	stu2x0_.summary_ AS summary_9_1_
FROM
	ls_stu2 stu2x0_
WHERE
	stu2x0_.id_ =?

不是很高大上的东西，自己的学习记录而已……