Kotlin+Vue+Spring Data JPA+MySQL 增查改删

概述:

1. Kotlin为后端开发语言,持久层是Spring Data JPA

2. 前后端分离，进行简单增查改删（CRUD）

3. 前端使用VUE

4. 数据库使用MySQL

往期内容

#	内容
01	React+Spring Boot JPA+MySQL 增查改删
02	Vue+Spring Boot JPA+MySQL 增查改删 增查改删
03	Vue+Spring Boot 文件操作，上传、预览和删除
04	Thymeleaf+Spring Boot 文件操作，上传、预览和删除

Vue前端代码，不再重复。以下是Kotlin后台代码

#EmployeeController.kt

package com.example.kotlinjpacrud.controller


import com.example.kotlinjpacrud.entity.Employee
import com.example.kotlinjpacrud.repositories.EmployeeRepository
import org.springframework.data.domain.Page import org.springframework.data.domain.Pageable import org.springframework.data.domain.Sort import org.springframework.data.web.PageableDefault import org.springframework.http.HttpStatus import org.springframework.http.ResponseEntity import org.springframework.web.bind.annotation.* import javax.validation.Valid  @RestController @RequestMapping("/api/employee") class EmployeeController(private val employeeRepository: EmployeeRepository) {   /**  * 获取所有员工分页  * 以字段Id为降序  * 没有为3条记录  */  @GetMapping  fun getAllEmployees(@PageableDefault(sort = ["id"], direction = Sort.Direction.DESC, size = 3) pageable: Pageable): Page<Employee> {  return employeeRepository.findAll(pageable)  }   /**  * 新增员工  */  @PostMapping  fun createEmployee(@Valid @RequestBody employee: Employee): Employee {  return employeeRepository.save(employee)  }   /**  * 根据ID获取员工  */  @GetMapping("/{id}")  fun getEmployeeById(@PathVariable(value = "id") employeeId: Long): ResponseEntity<Employee> {  return employeeRepository.findById(employeeId)  .map { employee -> ResponseEntity.ok(employee) }  .orElse(ResponseEntity.notFound().build())  }   /**  * 修改员工  */  @PutMapping  fun updateEmployeeById(@Valid @RequestBody newEmployee: Employee): ResponseEntity<Employee> {   return employeeRepository.findById(newEmployee.id)  .map { existingArticle ->  val updatedArticle: Employee = existingArticle  .copy(name = newEmployee.name,  gender = newEmployee.gender,  age = newEmployee.age,  introduce = newEmployee.introduce)  ResponseEntity.ok().body(employeeRepository.save(updatedArticle))  }.orElse(ResponseEntity.notFound().build())  }   /**  * 根据ID删除  */  @DeleteMapping("/{id}")  fun deleteEmployeeById(@PathVariable(value = "id") employeeId: Long): ResponseEntity<Void> {  return employeeRepository.findById(employeeId)  .map { deleteEmployee ->  employeeRepository.delete(deleteEmployee)  ResponseEntity<Void>(HttpStatus.OK)  }.orElse(ResponseEntity.notFound().build())   } }   

#Employee.kt

package com.example.kotlinjpacrud.entity

import com.example.kotlinjpacrud.enums.Gender
import javax.persistence.Entity
import javax.persistence.GeneratedValue
import javax.persistence.Id  @Entity data class Employee(  @Id @GeneratedValue  var id: Long =0,  var name: String ="",  var gender: Gender = Gender.MALE,  var age: Int =0,  var introduce: String ="" ) 

#EmployeeRepository.tk

package com.example.kotlinjpacrud.repositories

import com.example.kotlinjpacrud.entity.Employee
import org.springframework.data.jpa.repository.JpaRepository
import org.springframework.stereotype.Repository

@Repository
interface EmployeeRepository :JpaRepository<Employee,Long> {
}