SpringBoot整合Kotlin构建Web服务的方法示例

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：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>

<groupId>com.edurt.ski</groupId>
<artifactId>springboot-kotlin-integration</artifactId>
<version>1.0.0</version>
<packaging>jar</packaging>

<name>springboot kotlin integration</name>
<description>SpringBoot Kotlin Integration is a open source springboot, kotlin integration example.</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<!-- plugin config -->
<plugin.maven.kotlin.version>1.2.71</plugin.maven.kotlin.version>
</properties>

<dependencies>
<!-- spring boot -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- kotlin -->
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-kotlin</artifactId>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-stdlib-jdk8</artifactId>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-reflect</artifactId>
</dependency>
</dependencies>

<build>
<sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
<testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<artifactId>kotlin-maven-plugin</artifactId>
<groupId>org.jetbrains.kotlin</groupId>
<configuration>
<args>
<arg>-Xjsr305=strict</arg>
</args>
<compilerPlugins>
<plugin>spring</plugin>
<plugin>jpa</plugin>
<plugin>all-open</plugin>
</compilerPlugins>
<pluginOptions>
<option>all-open:annotation=javax.persistence.Entity</option>
</pluginOptions>
</configuration>
<dependencies>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-allopen</artifactId>
<version>${plugin.maven.kotlin.version}</version>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-noarg</artifactId>
<version>${plugin.maven.kotlin.version}</version>
</dependency>
</dependencies>
<executions>
<execution>
<id>kapt</id>
<goals>
<goal>kapt</goal>
</goals>
<configuration>
<sourceDirs>
<sourceDir>src/main/kotlin</sourceDir>
</sourceDirs>
<annotationProcessorPaths>
<annotationProcessorPath>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<version>${project.parent.version}</version>
</annotationProcessorPath>
</annotationProcessorPaths>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>

</project>

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.ski

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication

@SpringBootApplication
class SpringBootKotlinIntegration

fun main(args: Array<String>) {
runApplication<SpringBootKotlinIntegration>(*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.controller

import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.RestController

@RestController
class 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

<!-- mustache -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mustache</artifactId>
</dependency>

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

<h1>Hello, Kotlin</h1>

创建页面转换器HelloView

package com.edurt.ski.view

import org.springframework.stereotype.Controller
import org.springframework.ui.Model
import org.springframework.web.bind.annotation.GetMapping

@Controller
class HelloView {

@GetMapping(value = "hello_view")
fun helloView(model: Model): String {
return "hello"
}

}

浏览器访问http://localhost:8080/hello_view即可看到页面内容

添加数据持久化功能

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)

<!-- data jpa and db -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>

创建User实体

package com.edurt.ski.model

import javax.persistence.Entity
import javax.persistence.GeneratedValue
import 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.support

import com.edurt.ski.model.UserModel
import org.springframework.data.repository.PagingAndSortingRepository

interface UserSupport : PagingAndSortingRepository<UserModel, Long> {

}

创建UserService服务类

package com.edurt.ski.service

import com.edurt.ski.model.UserModel

interface UserService {

/**
* save model to db
*/
fun save(model: UserModel): UserModel

}

创建UserServiceImpl实现类

package com.edurt.ski.service

import com.edurt.ski.model.UserModel
import com.edurt.ski.support.UserSupport
import 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.controller

import com.edurt.ski.model.UserModel
import com.edurt.ski.service.UserService
import org.springframework.web.bind.annotation.PathVariable
import org.springframework.web.bind.annotation.PostMapping
import org.springframework.web.bind.annotation.RequestMapping
import 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<UserModel>

修改UserServiceImpl增加以下代码

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

修改UserController增加以下代码

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

创建UserView文件渲染User数据

package com.edurt.ski.view

import com.edurt.ski.service.UserService
import org.springframework.data.domain.PageRequest
import org.springframework.stereotype.Controller
import org.springframework.ui.Model
import org.springframework.ui.set
import org.springframework.web.bind.annotation.GetMapping

@Controller
class 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http://localhost: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

<!-- test -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</exclusion>
<exclusion>
<groupId>org.mockito</groupId>
<artifactId>mockito-core</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<scope>test</scope>
</dependency>

创建UserServiceTest文件进行测试UserService功能

package com.edurt.ski

import com.edurt.ski.service.UserService
import org.junit.jupiter.api.AfterAll
import org.junit.jupiter.api.Test
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.context.SpringBootTest
import 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：GitHub

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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