Of Stack

Spring Boot and Kotlin handle the Web form submission method

  • 2021-01-02 21:51:55
  • OfStack

When we were doing web development, we couldn't escape form submission. This article uses Spring Boot to create and submit a form using Kotlin.

Here we add the processing of form submissions to the previous Spring Boot and Kotlin project which rendered web Views using the Freemarker template engine.

build. gradle file has not changed, here post 1 full build. gradle 


group 'name.quanke.kotlin'
version '1.0-SNAPSHOT'

buildscript {
  ext.kotlin_version = '1.2.10'
  ext.spring_boot_version = '1.5.4.RELEASE'
  repositories {
    mavenCentral()
  }
  dependencies {
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    classpath("org.springframework.boot:spring-boot-gradle-plugin:$spring_boot_version")

//    Kotlin integration SpringBoot The default parameter-free constructor, which sets all classes by default open Class plug-in 
    classpath("org.jetbrains.kotlin:kotlin-noarg:$kotlin_version")
    classpath("org.jetbrains.kotlin:kotlin-allopen:$kotlin_version")
  }
}

apply plugin: 'kotlin'
apply plugin: "kotlin-spring" // See https://kotlinlang.org/docs/reference/compiler-plugins.html#kotlin-spring-compiler-plugin
apply plugin: 'org.springframework.boot'

jar {
  baseName = 'chapter11-5-4-service'
  version = '0.1.0'
}
repositories {
  mavenCentral()
}

dependencies {
  compile "org.jetbrains.kotlin:kotlin-stdlib-jre8:$kotlin_version"
  compile "org.springframework.boot:spring-boot-starter-web:$spring_boot_version"
  compile "org.springframework.boot:spring-boot-starter-thymeleaf:$spring_boot_version"
//  compile "com.fasterxml.jackson.module:jackson-module-kotlin:$kotlin_version"
  testCompile "org.springframework.boot:spring-boot-starter-test:$spring_boot_version"
  testCompile "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"

}

compileKotlin {
  kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
  kotlinOptions.jvmTarget = "1.8"
}

Create the entity class Hello 


/**
 * Created by http://quanke.name on 2018/1/12.
 */
data class Hello(var id: Long? = 0, var content: String? = "")

Create Controller 


import name.quanke.kotlin.chaper11_5_4.entity.Hello
import org.springframework.stereotype.Controller
import org.springframework.ui.ModelMap
import org.springframework.web.bind.annotation.ModelAttribute
import org.springframework.web.bind.annotation.PostMapping
import org.springframework.web.bind.annotation.RequestMapping
/**
 * Created by http://quanke.name on 2018/1/10.
 */
@Controller
class HelloController {

  @RequestMapping("/")
  fun index(map: ModelMap): String {
//    /  join 1 Three properties that are used to read in the template 
    map.addAttribute("host", "http://quanke.name")
    map.addAttribute("hello",Hello())
    // return Name of the template file, corresponding to src/main/resources/templates/index.html
    return "index"
  }

  @PostMapping("/hello")
  fun helloPostSubmit(@ModelAttribute hello: Hello): String {
    return "result"
  }
}

Page display layer

src/main/resources/templates/index.html 


<!DOCTYPE html>
<html xmlns:th="http://www.w3.org/1999/xhtml">
<head lang="en">
  <title>quanke.name</title>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
</head>
<body>
<h1 th:text="${host}">Hello World</h1>
<h1>Form</h1>
<form action="#" th:action="@{/hello}" th:object="${hello}" method="post">
  <p>Id: <input type="text" th:field="*{id}"/></p>
  <p>Message: <input type="text" th:field="*{content}"/></p>
  <p><input type="submit" value="Submit"/> <input type="reset" value="Reset"/></p>
</form>
</body>
</html>

src/main/resources/templates/result.html 


<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.w3.org/1999/xhtml">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
  <title>Title</title>
</head>
<body>
<h1>Result</h1>
<p th:text="'id: ' + ${hello.id}"/>
<p th:text="'content: ' + ${hello.content}"/>
<a href="/" rel="external nofollow" >Submit another message</a>
</body>
</html>

Spring Boot start 


import org.springframework.boot.SpringApplication
import org.springframework.boot.autoconfigure.SpringBootApplication
/**
 * Created by http://quanke.name on 2018/1/9.
 */

@SpringBootApplication
class Application

fun main(args: Array<String>) {
  SpringApplication.run(Application::class.java, *args)
}

Start the project, visit ttp://localhost:8080/:

Reference: https: / / spring io/guides/gs/handling - form - submission /

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