JarCastingkotlin-neo4j
kotlin-neo4j is a wrapper of 'org.neo4j.driver:neo4j-java-driver' and written by Kotlin.
- Easy to use with Kotlin: declarative style
- Kotlin std naming styles: stringOrNull, int("key")
- Support Sl4j Logger
Gradle
implementation "io.github.erictsangx:kotlin-neo4j:0.0.6"
Maven
<dependency>
<groupId>io.github.erictsangx</groupId>
<artifactId>kotlin-neo4j</artifactId>
<version>0.0.6</version>
</dependency>
Examples
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.kotlin.KotlinModule
import github.etx.neo4j.DefaultNeoSerializer
import github.etx.neo4j.NeoLogging
import github.etx.neo4j.NeoQuery
import github.etx.neo4j.destruct
import org.neo4j.driver.v1.AuthTokens
import org.neo4j.driver.v1.Config
import org.neo4j.driver.v1.GraphDatabase
import org.slf4j.LoggerFactory
data class User(val name: String, val age: Int?)
class HelloWorld {
companion object {
@JvmStatic
fun main(args: Array<String>) {
val logger = LoggerFactory.getLogger(HelloWorld::class.java)
val driver = GraphDatabase.driver(
"bolt://127.0.0.1",
AuthTokens.basic("neo4j", "neo4j")
, Config.build().withLogging(NeoLogging(logger)).toConfig()
)
val neo = NeoQuery(driver, DefaultNeoSerializer())
neo.submit("CREATE (u:User { name: {name}, age: {age} })", User("Alice", 18).destruct())
neo.submit("CREATE (u:User { name: {name}, age: {age} })", User("Bob", null).destruct())
val alice = neo.submit("MATCH (u:User { name:{name} }) RETURN u", mapOf("name" to "Alice"))
.map { it.unwrap("u") }
.map { User(it.string("name"), it.intOrNull("age")) }
.singleOrNull()
println(alice) //User(name=Alice, age=18)
//or
val aliceB = neo.submit("MATCH (u:User { name:{name} }) RETURN u", mapOf("name" to "Alice"))
.unwrap("u")
.let {
User(it.string("name"), it.intOrNull("age"))
}
println(aliceB) //User(name=Alice, age=18)
//You can use with Jackson
val mapper = ObjectMapper().registerModule(KotlinModule())
val users = neo.submit("MATCH (u:User) WHERE u.age IS NULL RETURN u")
.map { it.unwrap("u") }
.map { mapper.convertValue(it.asMap(), User::class.java) }
.toList()
println(users) //[User(name=Bob, age=null)]
driver.close()
}
}
}