Spring Boot ログイン画面

package com.example.securingweb

import org.springframework.context.annotation.Configuration
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer

@Configuration
class MvcConfig : WebMvcConfigurer {
    override fun addViewControllers(registry: ViewControllerRegistry) {
        registry.addViewController("/home").setViewName("home")
        registry.addViewController("/").setViewName("home")
        registry.addViewController("/hello").setViewName("hello")
        registry.addViewController("/login").setViewName("login")
    }
}

implementation("org.springframework.boot:spring-boot-starter-security")
implementation("org.thymeleaf.extras:thymeleaf-extras-springsecurity6")
testImplementation("org.springframework.security:spring-security-test")

plugins {
    kotlin("jvm") version "1.9.25"
    kotlin("plugin.spring") version "1.9.25"
    id("org.springframework.boot") version "3.5.7"
    id("io.spring.dependency-management") version "1.1.7"
}

group = "com.example"
version = "0.0.1-SNAPSHOT"
java.sourceCompatibility = JavaVersion.VERSION_17

repositories {
    mavenCentral()
}

dependencies {
    implementation("org.springframework.boot:spring-boot-starter-web")
    implementation("org.springframework.boot:spring-boot-starter-thymeleaf")
    implementation("org.jetbrains.kotlin:kotlin-reflect")
    implementation("org.springframework.boot:spring-boot-starter-security")
    implementation("org.thymeleaf.extras:thymeleaf-extras-springsecurity6")
    testImplementation("org.springframework.security:spring-security-test")
    testImplementation("org.springframework.boot:spring-boot-starter-test")
}

kotlin {
    jvmToolchain(17)
    compilerOptions {
        freeCompilerArgs.addAll("-Xjsr305=strict")
    }
}

tasks.withType<Test> {
    useJUnitPlatform()
}

package com.example.securingweb

import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.security.config.annotation.web.builders.HttpSecurity
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity
import org.springframework.security.config.annotation.web.invoke
import org.springframework.security.core.userdetails.User
import org.springframework.security.core.userdetails.UserDetailsService
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder
import org.springframework.security.crypto.password.PasswordEncoder
import org.springframework.security.provisioning.InMemoryUserDetailsManager
import org.springframework.security.web.SecurityFilterChain

@Configuration
@EnableWebSecurity
class WebSecurityConfig {

    @Bean
    fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
        http {
            // Kotlin security extensions allow concise DSL instead of builder-style lambdas
            authorizeHttpRequests {
                authorize("/", permitAll)
                authorize("/home", permitAll)
                authorize(anyRequest, authenticated)
            }
            formLogin {
                loginPage = "/login"
                permitAll()
            }
            logout {
                permitAll()
            }
        }

        return http.build()
    }

    @Bean
    fun passwordEncoder(): PasswordEncoder {
        return BCryptPasswordEncoder()
    }

    @Bean
    fun userDetailsService(): UserDetailsService {
        val encoder = BCryptPasswordEncoder()
        val user = User.builder()
            .username("user")
            .password(encoder.encode("password"))
            .roles("USER")
            .build()

        return InMemoryUserDetailsManager(user)
    }
}

package com.example.securingweb

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

@SpringBootApplication
class SecuringWebApplication

fun main(args: Array<String>) {
    runApplication<SecuringWebApplication>(*args)
}