Ktor: Kotlin Web后端框架 Web backend framework for Kotlin 快速开始入门
Ktor 简介
Ktor 是一个用于在 Kotlin 中快速创建 web 应用程序的框架。
import org.jetbrains.ktor.netty.*
import org.jetbrains.ktor.routing.*
import org.jetbrains.ktor.application.*
import org.jetbrains.ktor.host.*
import org.jetbrains.ktor.http.*
import org.jetbrains.ktor.response.*
fun main(args: Array<String>) {
embeddedServer(Netty, 8080) {
routing {
get("/") {
call.respondText("Hello, world!", ContentType.Text.Html)
}
}
}.start(wait = true)
}
创建工程
首先使用 IDEA 创建标准 Gradle+Kotlin 工程。
然后分别添加：
BlogApp.kt logback.xml
目录结构如下：
$ tree
.
├── build.gradle
├── settings.gradle
└── src
├── main
│ ├── java
│ ├── kotlin
│ │ └── com
│ │ └── easy
│ │ └── kotlin
│ │ └── BlogApp.kt
│ └── resources
│ └── logback.xml
└── test
├── java
├── kotlin
└── resources
12 directories, 4 files
在build.gradle中配置 Ktor 依赖
group 'com.easy.kotlin'
version '1.0-SNAPSHOT'
buildscript {
ext.kotlin_version = '1.1.3-2'
ext.ktor_version = '0.4.0' // ktor 版本
repositories {
mavenCentral()
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}
}
apply plugin: 'java'
apply plugin: 'kotlin'
apply plugin: 'application' // application plugin
mainClassName = 'com.easy.kotlin.BlogAppKt' // main class
sourceCompatibility = 1.8
repositories {
mavenCentral()
maven { url "http://dl.bintray.com/kotlin/ktor" }
maven { url "https://dl.bintray.com/kotlin/kotlinx" }
}
dependencies {
...
compile "org.jetbrains.ktor:ktor-core:$ktor_version"
compile "org.jetbrains.ktor:ktor-netty:$ktor_version"
compile "ch.qos.logback:logback-classic:1.2.1"
}
kotlin {
experimental {
coroutines "enable"
}
}
其中，
compile "org.jetbrains.ktor:ktor-core:$ktor_version"
compile "org.jetbrains.ktor:ktor-netty:$ktor_version"
是 ktor 核心依赖。
BlogApp.kt
package com.easy.kotlin
import org.jetbrains.ktor.application.Application
import org.jetbrains.ktor.application.install
import org.jetbrains.ktor.features.CallLogging
import org.jetbrains.ktor.features.DefaultHeaders
import org.jetbrains.ktor.host.embeddedServer
import org.jetbrains.ktor.http.ContentType
import org.jetbrains.ktor.netty.Netty
import org.jetbrains.ktor.response.respondText
import org.jetbrains.ktor.routing.Routing
import org.jetbrains.ktor.routing.get
import java.util.*
fun Application.module() {
install(DefaultHeaders)
install(CallLogging)
install(Routing) {
get("/") {
var html = "<li><a href = 'hello'>hello</a></li>"
html += "<li><a href = 'now'>now</a></li>"
call.respondText(html, ContentType.Text.Html)
}
get("/hello") {
call.respondText("Hello, Ktor !", ContentType.Text.Html)
}
get("/now") {
call.respondText("Now time is : ${Date()}", ContentType.Text.Html)
}
}
}
fun main(args: Array<String>) {
embeddedServer(Netty, 8080, watchPaths = listOf("BlogAppKt"), module = Application::module).start()
}
logback.xml
<configuration>
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>%d{YYYY-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
</encoder>
</appender>
<root level="trace">
<appender-ref ref="STDOUT"/>
</root>
<logger name="org.eclipse.jetty" level="INFO"/>
<logger name="io.netty" level="INFO"/>
</configuration>
运行结果
启动应用：
输出日志：
22:40:44: Executing external task 'run'...
:compileKotlin
Using kotlin incremental compilation
:compileJava NO-SOURCE
:copyMainKotlinClasses
:processResources
:classes
:run
2017-09-05 22:40:53.701 [main] DEBUG ktor.application - Java Home: /Library/Java/JavaVirtualMachines/jdk1.8.0_40.jdk/Contents/Home
2017-09-05 22:40:53.712 [main] DEBUG ktor.application - Class Loader: sun.misc.Launcher$AppClassLoader@73d16e93: [/Users/jack/easykotlin/ktor_demo/build/classes/java/main/, /Users/jack/easykotlin/ktor_demo/build/resources/main/, /Users/jack/.gradle/caches/modules-2/files-2.1/org.jetbrains.ktor/ktor-netty/0.4.0/f8809d15d9b447b669e8514f14addcb3586dcd26/ktor-netty-0.4.0.jar, /Users/jack/.gradle/caches/modules-2/files-2.1/org.jetbrains.ktor/ktor-hosts-common/0.4.0/bec3be6cc48a989347a7d3048266aff412d16668/ktor-hosts-common-0.4.0.jar, /Users/jack/.gradle/caches/modules-2/files-2.1/org.jetbrains.ktor/ktor-core/0.4.0/be0937d74f19862e8087b08a3b2306de65aa6f12/ktor-core-0.4.0.jar, ...
2017-09-05 22:40:53.717 [main] INFO ktor.application - No ktor.deployment.watch patterns match classpath entries, automatic reload is not active
2017-09-05 22:40:54.364 [main] TRACE ktor.application - Application started: org.jetbrains.ktor.application.Application@f78a47e
浏览器访问： http://127.0.0.1:8080/
完整工程示例代码
https://github.com/EasyKotlin/ktor_demo
参考资料：
《Kotlin极简教程》 正式上架：
Official on shelves: Kotlin Programming minimalist tutorial