今天我们尝试Spring Boot整合Kotlin，并决定建立一个非常简单的Spring Boot微服务，使用Kotlin作为编程语言进行编码构建。

创建一个简单的Spring Boot应用程序。我会在这里使用maven构建项目：

    
        
     
      4.0.0
         
     
      com.edurt.ski
         
     
      springboot-kotlin-integration
         
     
      1.0.0
         
     
      jar
         
     
      springboot kotlin integration
         
     
      SpringBoot Kotlin Integration is a open source springboot, kotlin integration example.
         
             
      
       org.springframework.boot
              
      
       spring-boot-starter-parent
              
      
       2.1.3.RELEASE
              
       
          
         
             
      
       UTF-8
              
      
       UTF-8
              
      
       1.8
              
              
      
       1.2.71
          
         
             
              
                  
       
        org.springframework.boot
                   
       
        spring-boot-starter-web
               
              
              
                  
       
        com.fasterxml.jackson.module
                   
       
        jackson-module-kotlin
               
              
                  
       
        org.jetbrains.kotlin
                   
       
        kotlin-stdlib-jdk8
               
              
                  
       
        org.jetbrains.kotlin
                   
       
        kotlin-reflect
               
          
         
             
      
       ${project.basedir}/src/main/kotlin
              
      
       ${project.basedir}/src/test/kotlin
              
                  
                       
        
         org.springframework.boot
                        
        
         spring-boot-maven-plugin
                    
                   
                       
        
         kotlin-maven-plugin
                        
        
         org.jetbrains.kotlin
                        
                            
          
          
           -Xjsr305=strict
           
                             
          
          
           spring
           
          
           jpa
           
          
           all-open
           
                             
          
          all-open:annotation=javax.persistence.Entity 
                         
                        
                            
          
          
           org.jetbrains.kotlin
           
          
           kotlin-maven-allopen
           
          
           ${plugin.maven.kotlin.version}
           
                             
          
          
           org.jetbrains.kotlin
           
          
           kotlin-maven-noarg
           
          
           ${plugin.maven.kotlin.version}
           
                         
                        
                            
          
          
           kapt
           
           
           
            kapt
            
           
           
            
            
             src/main/kotlin
             
            
            
             
             
              org.springframework.boot
              
             
              spring-boot-configuration-processor
              
             
              ${project.parent.version}
              
             
            
           
                         
                    
               
          
     
    

添加所有必需的依赖项：

• kotlin-stdlib-jdk8 kotlin jdk8的lib包
• kotlin-reflect kotlin反射包

一个简单的应用类：

package com.edurt.skiimport org.springframework.boot.autoconfigure.SpringBootApplicationimport org.springframework.boot.runApplication@SpringBootApplicationclass SpringBootKotlinIntegrationfun main(args: Array
    
     ) {    runApplication
     
      (*args)}
     
    

添加Rest API接口功能

---

创建一个HelloController Rest API接口,我们只提供一个简单的get请求获取hello,kotlin输出信息:

package com.edurt.ski.controllerimport org.springframework.web.bind.annotation.GetMappingimport org.springframework.web.bind.annotation.RestController@RestControllerclass HelloController {    @GetMapping(value = "hello")    fun hello(): String {        return "hello,kotlin"    }}

修改SpringBootKotlinIntegration文件增加以下设置扫描路径

@ComponentScan(value = [    "com.edurt.ski",    "com.edurt.ski.controller"])

添加页面功能

---

• 修改pom.xml文件增加以下页面依赖

    
        
     
      org.springframework.boot
         
     
      spring-boot-starter-mustache
     
    

• 在src/main/resources路径下创建templates文件夹
• 在templates文件夹下创建一个名为hello.mustache的页面文件

Hello, Kotlin

• 创建页面转换器HelloView

package com.edurt.ski.viewimport org.springframework.stereotype.Controllerimport org.springframework.ui.Modelimport org.springframework.web.bind.annotation.GetMapping@Controllerclass HelloView {    @GetMapping(value = "hello_view")    fun helloView(model: Model): String {        return "hello"    }}

• 浏览器访问:8080/hello_view即可看到页面内容

添加数据持久化功能

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• 修改pom.xml文件增加以下依赖(由于测试功能我们使用h2内存数据库)

    
        
     
      org.springframework.boot
         
     
      spring-boot-starter-data-jpa
     
    
        
     
      com.h2database
         
     
      h2
         
     
      runtime
     
    

• 创建User实体

package com.edurt.ski.modelimport javax.persistence.Entityimport javax.persistence.GeneratedValueimport javax.persistence.Id@Entity//class UserModel(//        @Id//        @GeneratedValue//        private var id: Long? = 0,//        private var name: String//)class UserModel {        @Id        @GeneratedValue        var id: Long? = 0                get() = field                set        var name: String? = null                get() = field                set}

• 创建UserSupport dao数据库操作工具类

package com.edurt.ski.supportimport com.edurt.ski.model.UserModelimport org.springframework.data.repository.PagingAndSortingRepositoryinterface UserSupport : PagingAndSortingRepository
    
      {}
    

• 创建UserService服务类

package com.edurt.ski.serviceimport com.edurt.ski.model.UserModelinterface UserService {    /**     * save model to db     */    fun save(model: UserModel): UserModel}

• 创建UserServiceImpl实现类

package com.edurt.ski.serviceimport com.edurt.ski.model.UserModelimport com.edurt.ski.support.UserSupportimport org.springframework.stereotype.Service@Service(value = "userService")class UserServiceImpl(private val userSupport: UserSupport) : UserService {    override fun save(model: UserModel): UserModel {        return this.userSupport.save(model)    }}

• 创建用户UserController进行持久化数据

package com.edurt.ski.controllerimport com.edurt.ski.model.UserModelimport com.edurt.ski.service.UserServiceimport org.springframework.web.bind.annotation.PathVariableimport org.springframework.web.bind.annotation.PostMappingimport org.springframework.web.bind.annotation.RequestMappingimport org.springframework.web.bind.annotation.RestController@RestController@RequestMapping(value = "user")class UserController(private val userService: UserService) {    @PostMapping(value = "save/{name}")    fun save(@PathVariable name: String): UserModel {        val userModel = UserModel()//        userModel.id = 1        userModel.name = name        return this.userService.save(userModel)    }}

• 使用控制台窗口执行以下命令保存数据

curl -X POST http://localhost:8080/user/save/qianmoQ

收到返回结果

{"id":1,"name":"qianmoQ"}

表示数据保存成功

增加数据读取渲染功能

---

• 修改UserService增加以下代码

/** * get all model */fun getAll(page: Pageable): Page
    

• 修改UserServiceImpl增加以下代码

override fun getAll(page: Pageable): Page
    
      {    return this.userSupport.findAll(page)}
    

• 修改UserController增加以下代码

@GetMapping(value = "list")fun get(): Page
    
      = this.userService.getAll(PageRequest(0, 10))
    

• 创建UserView文件渲染User数据

package com.edurt.ski.viewimport com.edurt.ski.service.UserServiceimport org.springframework.data.domain.PageRequestimport org.springframework.stereotype.Controllerimport org.springframework.ui.Modelimport org.springframework.ui.setimport org.springframework.web.bind.annotation.GetMapping@Controllerclass UserView(private val userService: UserService) {    @GetMapping(value = "user_view")    fun helloView(model: Model): String {        model["users"] = this.userService.getAll(PageRequest(0, 10))        return "user"    }}

• 创建user.mustache文件渲染数据(自行解析返回数据即可)

{
   {users}}

• 浏览器访问:8080/user_view即可看到页面内容

增加单元功能

---

• 修改pom.xml文件增加以下依赖

    
        
     
      org.springframework.boot
         
     
      spring-boot-starter-test
         
     
      test
         
             
                  
       
        junit
                   
       
        junit
               
              
                  
       
        org.mockito
                   
       
        mockito-core
               
          
     
    
        
     
      org.junit.jupiter
         
     
      junit-jupiter-engine
         
     
      test
     
    

• 创建UserServiceTest文件进行测试UserService功能

package com.edurt.skiimport com.edurt.ski.service.UserServiceimport org.junit.jupiter.api.AfterAllimport org.junit.jupiter.api.Testimport org.springframework.beans.factory.annotation.Autowiredimport org.springframework.boot.test.context.SpringBootTestimport org.springframework.data.domain.PageRequest@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)class UserServiceTest(@Autowired private val userService: UserService) {    @Test    fun `get all`() {        println(">> Assert blog page title, content and status code")        val entity = this.userService.getAll(PageRequest(0, 1))        print(entity.totalPages)    }}

源码地址：