MavenによるJavaコネクター

MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases using the standard JDBC API.

事前要件

• デフォルトポート番号3306、ローカルホストで稼働しているMariaDBもしくはMySQLサーバー
• Java バージョン8以上
• Maven

Mavenプロジェクトの作成

シンプルなJavaプロジェクトをMavenで作成します。

mvn archetype:generate -DgroupId=com.mycompany.app -DartifactId=my-app 
-DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

"com.mycompany.app"と"my-app"は適切な値に置き換える。

新しいプロジェクトはmy-appフォルダーの中に作成されます。このフォルダーはMavenの構成を定義するpom.xmlを含みます。

MariaDB用Javaドライバーの取得

Declares driver in pom.xml (and setting java minimal version to 1.8) :

pom.file will then be :

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.mycompany.app</groupId>
    <artifactId>my-app</artifactId>
    <packaging>jar</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>my-app</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mariadb.jdbc</groupId>
            <artifactId>mariadb-java-client</artifactId>
            <version>2.1.2</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.6.0</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

Connection

Standard JDBC methods DriverManager.getConnection(String url, String user, String password) are used to connect to the database.

Basic url string is standardized for the MariaDB driver : jdbc:(mysql|mariadb):[replication:|failover:|sequential:|aurora:]//<hostDescription>[,<hostDescription>...]/[database][?<key1>=<value1>[&<key2>=<value2>]]

The MariaDB driver is registered automatically for a url that begins with "jdbc:mariadb:" or "jdbc:mysql:".

Assuming a server is installed on the local machine with default port 3306, the url String is then "jdbc:mariadb://localhost/".

Basic maven archetype has created a simple Java file App.java in src/main/java/com/mycompany/app. Update the file App.java with the following content: (assuming a server is installed on the local machine, with a user "root" with no password) :

package com.mycompany.app;

import java.sql.*;

public class App {

    public static void main( String[] args ) throws SQLException {
        //create connection for a server installed in localhost, with a user "root" with no password
        try (Connection conn = DriverManager.getConnection("jdbc:mariadb://localhost/", "root", null)) {
            // create a Statement
            try (Statement stmt = conn.createStatement()) {
                //execute query
                try (ResultSet rs = stmt.executeQuery("SELECT 'Hello World!'")) {
                    //position result to first
                    rs.first();
                    System.out.println(rs.getString(1)); //result is "Hello World!"
                }
            }
        }
    }
}

Compile project:

mvn install

Maven will automatically download the driver and compile the App file.

Run it using maven:

C:\temp\my-app>mvn exec:java -Dexec.mainClass="com.mycompany.app.App"
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building my-app 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- exec-maven-plugin:1.6.0:java (default-cli) @ my-app ---
Hello World!
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.837 s
[INFO] Finished at: 2017-10-25T11:16:06+02:00
[INFO] Final Memory: 10M/245M
[INFO] ------------------------------------------------------------------------

合わせて読む

• さらに詳しく MariaDB Connector/Jについて