在做web开发的时候，我们需要验证表单，确认用户提交的信息是安全的，比如用户名不能超过多少位，密码不能少于多少位等等。
那么如何在Spring Boot 与 Kotlin中验证表单信息？
在springmvc工程中，需要检查表单信息，表单信息验证主要通过注解的形式。
表单验证
下面我们在之前《Spring Boot 与 Kotlin使用Freemarker模板引擎渲染web视图》项目的基础上，增加表单验证。
build.gradle 文件增加依赖
compile "org.hibernate:hibernate-validator"
compile "org.apache.tomcat.embed:tomcat-embed-el"
完整的build.gradle文件
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整合SpringBoot的默认无参构造函数，默认把所有的类设置open类插件
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 = 'chapter11-5-5-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:$spring_boot_version"
compile "org.hibernate:hibernate-validator"
compile "org.apache.tomcat.embed:tomcat-embed-el"
testCompile "org.springframework.boot:spring-boot-starter-test:$spring_boot_version"
testCompile "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"
}
compileKotlin {
kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
kotlinOptions.jvmTarget = "1.8"
}
创建UserForm类
import javax.validation.constraints.Min
import javax.validation.constraints.NotNull
import javax.validation.constraints.Size
/**
* Created by http://quanke.name on 2018/1/12.
* https://stackoverflow.com/questions/36515094/kotlin-and-valid-spring-annotation
* https://stonesoupprogramming.com/2017/06/21/spring-bean-validation-example-jsr-303-in-kotlin/
*/
data class UserForm(@get:NotNull(message = "{name.required}") @get:Size(min = 2, max = 5,message = "{name.size}") var name: String? = "", @get:Min(18) var age: Int? = 0)
如果是Spring boot 可以不增加 @get注解，如果使用kotlin 语言实现必须加@get
这个实体类，在2个属性:name,age.它们各自有验证的注解：
- @Size(min=2, max=5) name的长度为2-30个字符
- @NotNull 不为空
- @Min(18)age不能小于18
创建WebController
import name.quanke.kotlin.chaper11_5_5.entity.UserForm
import org.springframework.stereotype.Controller
import org.springframework.validation.Errors
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.PostMapping
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter
import javax.validation.Valid
/**
* Created by http://quanke.name on 2018/1/12.
*/
@Controller
class WebController : WebMvcConfigurerAdapter() {
override fun addViewControllers(registry: ViewControllerRegistry?) {
registry!!.addViewController("/results").setViewName("results")
}
@GetMapping("/")
fun index(userForm: UserForm): String {
return "index"
}
@PostMapping("/")
fun checkPersonInfo(@Valid userForm: UserForm, errors: Errors): String {
val result: String = when {
//Test for errors
errors.hasErrors() -> "index"
else -> {
//Otherwise proceed to the next page
"redirect:/results"
}
}
return result
}
}
创建form表单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>Form</h1>
<form action="#" th:action="@{/}" th:object="${userForm}" method="post">
<table>
<tr>
<td>Name:</td>
<td><input type="text" th:field="*{name}" /></td>
<td th:if="${#fields.hasErrors('name')}" th:errors="*{name}">Name Error</td>
</tr>
<tr>
<td>Age:</td>
<td><input type="text" th:field="*{age}" /></td>
<td th:if="${#fields.hasErrors('age')}" th:errors="*{age}">Age Error</td>
</tr>
<tr>
<td><button type="submit">Submit</button></td>
</tr>
</table>
</form>
</body>
</html>
成功页面src/main/resources/templates/results.html
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<title>quanke</title>
</head>
<body>
<h1>quanke.name</h1>
Congratulations! You are old enough to sign up for this site
</body>
</html>
在src/main/resources/目录下增加ValidationMessages.properties文件
# \u8FD9\u91CC\u8981\u6CE8\u610F\u7F16\u7801\u95EE\u9898
name.required=\u540D\u5B57\u4E0D\u80FD\u4E3A\u7A7A
name.size=\u540D\u5B57\u957F\u5EA6\u8FD4\u56DE\u53EA\u80FD\u662F2-5
Spring Boot 启动
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)
}
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