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🗣 Wd提问: Kotlin MySQL

🤖 Ai回答:
Below is a concise “starter kit” that gets you from zero to CRUD in Kotlin with MySQL、
It covers:

1、Picking a driver
2、Adding the dependency (Gradle)
3、Opening / closing a connection
4、Plain JDBC (no extra libraries)
5、The same thing with the lightweight DSL Exposed (JetBrains)
6、A few tips on connection pooling, coroutines and reactive drivers

You can copy-paste the snippets and run them as-is after you create a test database.

1、Which driver?

MySQL Connector/J (Oracle’s official JDBC driver) – synchronous, blocking、
r2dbc-mysql – reactive, non-blocking, works with coroutines、
Exposed – JetBrains’ Kotlin SQL DSL, sits on top of JDBC.

2、Gradle (Kotlin DSL)

plugins {
kotlin(jvm) version 1.9.24
application
}

repositories { mavenCentral() }

dependencies {
implementation(mysql:mysql-connector-java:8.3.0) // JDBC driver
implementation(org.jetbrains.exposed:exposed-core:0.49.0) // optional DSL
implementation(org.jetbrains.exposed:exposed-jdbc:0.49.0)
implementation(com.zaxxer:HikariCP:5.1.0) // connection pool
}

application {
mainClass.set(demo.MainKt)
}

3、Database & table for the demo

CREATE DATABASE demo CHARACTER SET utf8mb4;
USE demo;
CREATE TABLE users(
id INT AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(100) NOT NULL
);

4、Plain JDBC in Kotlin

package demo

import java.sql.DriverManager
import java.sql.SQLException

object JdbcExample {
private const val URL = jdbc:mysql://localhost:3306/demo?serverTimezone=UTC
private const val USER = root
private const val PASSWORD = secret

fun run() {
// 1) Load driver (optional since JDBC 4)
Class.forName(com.mysql.cj.jdbc.Driver)

// 2) Get connection (use try-with-resources / use {})
DriverManager.getConnection(URL, USER, PASSWORD).use { conn -
conn.prepareStatement(INSERT INTO users(name) VALUES (?)).use { ps -
ps.setString(1, Alice)
ps.executeUpdate()
}

conn.prepareStatement(SELECT id, name FROM users).use { ps -
ps.executeQuery().use { rs -
while (rs.next()) {
println(User ${rs.getInt(id)}: ${rs.getString(name)})
}
}
}
} // connection closed automatically
}
}

fun main() = JdbcExample.run()

5、Same thing with Exposed (JetBrains DSL)

package demo

import org.jetbrains.exposed.dao.id.IntIdTable
import org.jetbrains.exposed.sql.*
import org.jetbrains.exposed.sql.transactions.transaction

object Users : IntIdTable(users) {
val name = varchar(name, 100)
}

object ExposedExample {
private const val URL = jdbc:mysql://localhost:3306/demo?serverTimezone=UTC
private const val USER = root
private const val PASSWORD = secret

fun run() {
Database.connect(
url = URL,
driver = com.mysql.cj.jdbc.Driver,
user = USER,
password = PASSWORD
)

transaction {
// Insert
Users.insert { it[name] = Bob }

// Select
Users.selectAll().forEach {
println(User ${it[Users.id]}: ${it[Users.name]})
}
}
}
}

fun main() = ExposedExample.run()

6、Production-grade extras

Connection pool
Replace the simple `Database.connect` with a HikariDataSource:

val ds = HikariDataSource(HikariConfig().apply {
jdbcUrl = URL
username = USER
password = PASSWORD
maximumPoolSize = 10
})
Database.connect(ds)

Coroutines / reactive
Use `r2dbc-mysql` + `kotlinx-coroutines-r2dbc`:

implementation(io.r2dbc:r2dbc-mysql:0.8.2)
implementation(org.jetbrains.kotlinx:kotlinx-coroutines-reactor)

SQL migrations
Flyway or Liquibase work great from Gradle tasks.

Date/Time
Use `java.time.*` types; MySQL Connector/J 8.x maps them automatically.

Security
Never hard-code credentials; use environment variables or a secrets manager.

That’s all you need to start talking to MySQL from Kotlin.

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