kotlin+springboot+mybatis-puls+mysql搭建gradle-web工程

kotlin+springboot+mybatis-puls+mysql搭建web工程

​ 前段时间研究了spring security及OAuth2系列之后，本来打算研究spring的，但是部门发生了一些情况，我转岗到了另一个部门，具体做内部CICD的产品，需要用kotlin开发，于是我需要从零开始学习Kotlin语言。于是我连忙找了本Kotlin的书籍看了几天主要的语法章节，想着需要做点demo让自己熟悉一下，于是有了这篇文章。

​ 本片主要讲怎么基于kotlin搭建springboot-web项目。

在IDEA上创建gradle项目

​ 在IDEA上创建kotlin项目有多种方式，这里我采用了如图的方式

引入所需依赖

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
    testCompile group: 'junit', name: 'junit', version: '4.12'
    implementation group: 'org.springframework.boot', name: 'spring-boot-starter-web', version: '2.4.4'
    implementation group: 'mysql', name: 'mysql-connector-java', version: '8.0.27'
    implementation group: 'com.baomidou', name: 'mybatis-plus-boot-starter', version: '3.4.3.3'

}

​ 这里引入springboot\mysql-connector-java\mybatis-plus等组件，用的是基于groovy语言构建的gradle脚本，不知道这么脚本怎么来的，怎么到https://mvnrepository.com/ maven仓库查找gradle对应的依赖脚本。

新建各个文件（dao\service\mapper\entity\controller)

新建启动类

@SpringBootApplication
@MapperScan("com.canway.app.dao")
open class MainApplicationClass

fun main(args: Array<String>) {
    runApplication<MainApplicationClass>(*args)
}

新建entity（user表）

import com.fasterxml.jackson.annotation.JsonFormat
import java.util.Date

class TUser {
    var id: Int? = null;

    var username: String? = null;

    var age: Int? = null;

    var sex: Int? = null;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", shape = JsonFormat.Shape.STRING)
    var createTime: Date? = null;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", shape = JsonFormat.Shape.STRING)
    var updateTime: Date? = null;
}

新建service/impl

import com.baomidou.mybatisplus.extension.plugins.pagination.Page
import com.canway.app.dto.PageQuery
import com.canway.app.entity.TUser

interface TUserService {

    fun queryById(id: Int): TUser?

    fun queryByPage(pageQuery: PageQuery): Page<TUser?>

    fun insert(tUser: TUser): TUser

    fun update(tUser: TUser): TUser

    fun deleteById(id: Int): Boolean
}

package com.canway.app.service.impl

import com.baomidou.mybatisplus.core.toolkit.Wrappers
import com.baomidou.mybatisplus.extension.plugins.pagination.Page
import com.canway.app.dao.TUserDao
import com.canway.app.dto.PageQuery
import com.canway.app.entity.TUser
import com.canway.app.service.TUserService
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.stereotype.Service

@Service
class TUserServiceImpl @Autowired constructor(private var tUserDao: TUserDao): TUserService{

    // 不同过在构造函数中注入属性的话，可以通过寻常注入方式
//    @Resource
//    private lateinit var tUserDao: TUserDao;

    override fun queryById(id: Int): TUser? {
        return tUserDao.queryById(id)
    }

    override fun queryByPage(pageQuery: PageQuery): Page<TUser?> {
        val wrapper = Wrappers.lambdaQuery<TUser>()
//        wrapper.like(TUser::getUsername, query.getUsername());
        //        wrapper.like(TUser::getUsername, query.getUsername());
        val page: Page<TUser?> = Page<TUser?>(pageQuery.getPageNum(), pageQuery.getPageSize(), true)
        val page1: Page<TUser?> = tUserDao.selectPage(page, wrapper)
        return page1
    }

    override fun insert(tUser: TUser): TUser {
        this.tUserDao.insert(tUser);
        return tUser;
    }

    override fun update(tUser: TUser): TUser {
        this.tUserDao.update(tUser);
        return tUser;
    }

    override fun deleteById(id: Int): Boolean {
        return this.tUserDao.deleteById(id) > 0
    }
}

新建dao

package com.canway.app.dao

import com.baomidou.mybatisplus.core.mapper.BaseMapper
import com.baomidou.mybatisplus.extension.plugins.pagination.Page
import com.canway.app.entity.TUser
import org.apache.ibatis.annotations.Param

interface TUserDao: BaseMapper<TUser> {
    /**
     * 通过ID查询单条数据
     *
     * @param id 主键
     * @return 实例对象
     */
    fun queryById(id: Int): TUser?

    /**
     * 查询指定行数据
     *
     * @param tUser 查询条件
     * @return 对象列表
     */
    fun queryByPage(page: Page<TUser?>?, @Param("tUser") tUser: TUser?): List<TUser?>?

    /**
     * 统计总行数
     *
     * @param tUser 查询条件
     * @return 总行数
     */
    fun count(tUser: TUser?): Long

    /**
     * 新增数据
     *
     * @param tUser 实例对象
     * @return 影响行数
     */
    override fun insert(tUser: TUser?): Int

    /**
     * 批量新增数据（MyBatis原生foreach方法）
     *
     * @param entities List<TUser> 实例对象列表
     * @return 影响行数
    </TUser> */
    fun insertBatch(@Param("entities") entities: List<TUser?>?): Int

    /**
     * 批量新增或按主键更新数据（MyBatis原生foreach方法）
     *
     * @param entities List<TUser> 实例对象列表
     * @return 影响行数
     * @throws org.springframework.jdbc.BadSqlGrammarException 入参是空List的时候会抛SQL语句错误的异常，请自行校验入参
    </TUser> */
    fun insertOrUpdateBatch(@Param("entities") entities: List<TUser?>?): Int

    /**
     * 修改数据
     *
     * @param tUser 实例对象
     * @return 影响行数
     */
    fun update(tUser: TUser?): Int

    /**
     * 通过主键删除数据
     *
     * @param id 主键
     * @return 影响行数
     */
    fun deleteById(id: Int?): Int
}

新建controller

package com.canway.app.controller

import com.baomidou.mybatisplus.extension.plugins.pagination.Page
import com.canway.app.dto.PageQuery
import com.canway.app.entity.TUser
import com.canway.app.service.TUserService
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.http.ResponseEntity
import org.springframework.web.bind.annotation.DeleteMapping
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.PathVariable
import org.springframework.web.bind.annotation.PostMapping
import org.springframework.web.bind.annotation.PutMapping
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RestController

@RestController
@RequestMapping("tUser")
class UserController {

    @Autowired
    private val tUserService: TUserService? = null

    @GetMapping("/hello")
    fun helloworld(): String {
        return "Hello world"
    }

    @GetMapping("{id}")
    fun queryById(@PathVariable("id") id: Int): ResponseEntity<TUser?> {
        return ResponseEntity.ok(this.tUserService?.queryById(id))
    }

    @PostMapping
    fun add(tUser: TUser): ResponseEntity<TUser> {
        return ResponseEntity.ok(this.tUserService?.insert(tUser));
    }

    @GetMapping
    fun queryByPage(query: PageQuery): ResponseEntity<Page<TUser?>> {
        return ResponseEntity.ok(this.tUserService?.queryByPage(query))
    }

    @PutMapping
    fun edit(tUser: TUser): ResponseEntity<TUser> {
        return ResponseEntity.ok(this.tUserService?.update(tUser))
    }

    @DeleteMapping
    fun deleteById(id: Int): ResponseEntity<Boolean> {
        return ResponseEntity.ok(this.tUserService?.deleteById(id))
    }
}

新建mybatis配置类

package com.canway.app.config

import com.baomidou.mybatisplus.annotation.DbType
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor
import com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration

@Configuration
open class MybatisPlusConfig {

    @Bean
    open fun mybatisPlusInterceptor(): MybatisPlusInterceptor{
        var interceptor = MybatisPlusInterceptor();
        //向Mybatis过滤器链中添加分页拦截器
        interceptor.addInnerInterceptor(PaginationInnerInterceptor(DbType.MYSQL))
        interceptor.addInnerInterceptor(OptimisticLockerInnerInterceptor())
        //还可以添加i他的拦截器
        return interceptor
    }
}

添加配置

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/java_web?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8
    username: root
    password: 123456
    hikari:
      minimum-idle: 1
      maximum-pool-size: 3
      connection-timeout: 5000

mybatis-plus:
  configuration:
    map-underscore-to-camel-case: true
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

总结

​ 基于kotlin+springboot+mybatis-plus+mysql的gradle-web项目到这里就结束，整个过程中还是让自己熟悉了一些kotlin的具体语法，像函数声明、变量、类的定义等，后续写业务的时候才能相对快速熟悉其它语法。