REST web服務已成為在web上應用程式整合的首選方式。在其核心中，REST定義了系統由客戶端互動的資源組成。這些資源以超媒體驅動的方式實現。Spring MVC為構建這些服務提供了堅實的基礎。但是，對於多域物件系統，即使實施REST web服務的最簡單原則也可能相當乏味，並且導致大量樣板程式碼。

Spring Data REST構建在Spring Data repositories之上，並自動將其匯出為REST資源。它利用超媒體來允許客戶端查詢儲存庫暴露的功能，並將這些資源自動整合到相關的超媒體功能中。

• 根據model，生成HAL風格的restful API
• 根據model，維護實體之間的關係
• 支援分頁
• 允許動態地過濾集合資源
• 允許通過處理Spring ApplicationEvents處理REST請求。
• 目前支援JPA，MongoDB，Neo4j，Solr，Cassandra，Gemfire。
• 支援自定義

將Spring Data REST新增到Spring Boot專案

dependencies {
    ...
    compile "org.springframework.boot:spring-boot-starter-data-rest:$spring_boot_version"
    ...
}

完整的build.gradle檔案

group 'name.quanke.kotlin'
 

version '1.0-SNAPSHOT'

buildscript {
    ext.kotlin_version = '1.2.10'
    ext.spring_boot_version = '1.5.4.RELEASE'
    ext.springfox_swagger2_version = '2.7.0'
    ext.mysql_version = '5.1.21'
    ext.mybatis_version = '1.1.1'
    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的預設無參建構函式，預設把所有的類設定open類外掛
        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'
apply plugin: "kotlin-jpa"  //https://stackoverflow.com/questions/32038177/kotlin-with-jpa-default-constructor-hell
jar {
    baseName = 'chapter11-6-7-service'
    version = '0.1.0'
}
repositories {
    mavenCentral()
}


dependencies {
    compile "org.jetbrains.kotlin:kotlin-stdlib-jre8:$kotlin_version"
    compile("org.jetbrains.kotlin:kotlin-reflect:${kotlin_version}")

    compile "org.springframework.boot:spring-boot-starter-data-jpa:$spring_boot_version"
    compile "org.springframework.boot:spring-boot-starter-data-rest:$spring_boot_version"
    compile "mysql:mysql-connector-java:$mysql_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"
}

建立物件User

import javax.persistence.*

/**
 * Created by http://quanke.name on 2018/1/10.
 */

@Entity
data class User(
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
        var id: Long = -1,
        @Column(nullable = false)
        var username: String = "",

        var password: String = ""


)

建立UserRepository

import name.quanke.kotlin.chaper11_6_7.entity.User
import org.springframework.data.jpa.repository.JpaRepository
import org.springframework.data.jpa.repository.Query
import org.springframework.data.repository.query.Param
import org.springframework.data.rest.core.annotation.RepositoryRestResource

@RepositoryRestResource(path="user")
interface UserRepository : JpaRepository<User, Long> {

    fun findByUsername(username: String): List<User>

    fun findByUsernameAndPassword(username: String, password: String?): User

    @Query("from User u where u.username=:username")
    fun findUser(@Param("username") username: String): User

}

配置

在application.yml檔案中增加

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver

啟動

import org.springframework.boot.SpringApplication
import org.springframework.boot.autoconfigure.SpringBootApplication


/**
 * Created by http://quanke.name on 2018/1/9.
 */

//參考：http://blog.csdn.net/soul_code/article/details/54108105

@SpringBootApplication
class Application

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

測試

訪問 127.0.0.1:8080/user

返回：

{
    "_embedded": {
        "users": [
            {
                "username": "http://gof.quanke.name",
                "password": "1111",
                "_links": {
                    "self": {
                        "href": "http://127.0.0.1:8083/user/73"
                    },
                    "user": {
                        "href": "http://127.0.0.1:8083/user/73"
                    }
                }
            },
            {
                "username": "java.quanke.name",
                "password": "12",
                "_links": {
                    "self": {
                        "href": "http://127.0.0.1:8083/user/74"
                    },
                    "user": {
                        "href": "http://127.0.0.1:8083/user/74"
                    }
                }
            },
            {
                "username": "test.quanke.name",
                "password": "aa",
                "_links": {
                    "self": {
                        "href": "http://127.0.0.1:8083/user/75"
                    },
                    "user": {
                        "href": "http://127.0.0.1:8083/user/75"
                    }
                }
            },
            {
                "username": "es.quanke.name",
                "password": "12",
                "_links": {
                    "self": {
                        "href": "http://127.0.0.1:8083/user/76"
                    },
                    "user": {
                        "href": "http://127.0.0.1:8083/user/76"
                    }
                }
            },
            {
                "username": "as.quanke.name",
                "password": "12",
                "_links": {
                    "self": {
                        "href": "http://127.0.0.1:8083/user/77"
                    },
                    "user": {
                        "href": "http://127.0.0.1:8083/user/77"
                    }
                }
            },
            {
                "username": "vertx.quanke.name",
                "password": "12",
                "_links": {
                    "self": {
                        "href": "http://127.0.0.1:8083/user/78"
                    },
                    "user": {
                        "href": "http://127.0.0.1:8083/user/78"
                    }
                }
            }
        ]
    },
    "_links": {
        "self": {
            "href": "http://127.0.0.1:8083/user{?page,size,sort}",
            "templated": true
        },
        "profile": {
            "href": "http://127.0.0.1:8083/profile/user"
        },
        "search": {
            "href": "http://127.0.0.1:8083/user/search"
        }
    },
    "page": {
        "size": 20,
        "totalElements": 6,
        "totalPages": 1,
        "number": 0
    }
}

訪問 127.0.0.1:8083/user/73

注意： 73 是user id 根據自己的實際情況測試

返回：

{
    "username": "http://gof.quanke.name",
    "password": "1111",
    "_links": {
        "self": {
            "href": "http://127.0.0.1:8083/user/73"
        },
        "user": {
            "href": "http://127.0.0.1:8083/user/73"
        }
    }
}

Spring Data REST 能做的事情很多，這篇文章先介紹到這裡，先在這裡埋個坑，之後會出更加詳細的文章說Spring Data REST。

更多Spring Boot 和 kotlin相關內容

參考