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Use Java and JDBC with Azure Database for MySQL - Flexible Server

  • Άρθρο

This article demonstrates creating a sample application that uses Java and JDBC to store and retrieve information in Azure Database for MySQL Flexible Server.

JDBC is the standard Java API to connect to traditional relational databases.

In this article, we'll include two authentication methods: Microsoft Entra authentication and MySQL authentication. The Passwordless tab shows the Microsoft Entra authentication and the Password tab shows the MySQL authentication.

Microsoft Entra authentication is a mechanism for connecting to Azure Database for MySQL Flexible Server using identities defined in Microsoft Entra ID. With Microsoft Entra authentication, you can manage database user identities and other Microsoft services in a central location, which simplifies permission management.

MySQL authentication uses accounts stored in MySQL. If you choose to use passwords as credentials for the accounts, these credentials will be stored in the user table. Because these passwords are stored in MySQL, you'll need to manage the rotation of the passwords by yourself.

Prerequisites

  • An Azure account with an active subscription.

If you don't have an Azure subscription, create an Azure free account before you begin. Currently, with an Azure free account, you can try Azure Database for MySQL - Flexible Server free for 12 months. For more information, see Use an Azure free account to try Azure Database for MySQL - Flexible Server for free.

Prepare the working environment

First, use the following command to set up some environment variables.

export AZ_RESOURCE_GROUP=database-workshop
export AZ_DATABASE_NAME=<YOUR_DATABASE_NAME>
export AZ_LOCATION=<YOUR_AZURE_REGION>
export AZ_MYSQL_AD_NON_ADMIN_USERNAME=demo-non-admin
export AZ_USER_IDENTITY_NAME=<YOUR_USER_ASSIGNED_MANAGED_IDENTITY_NAME>
export CURRENT_USERNAME=$(az ad signed-in-user show --query userPrincipalName -o tsv)
export CURRENT_USER_OBJECTID=$(az ad signed-in-user show --query id -o tsv)

Replace the placeholders with the following values, which are used throughout this article:

  • <YOUR_DATABASE_NAME>: The name of your Azure Database for MySQL Flexible Server instance, which should be unique across Azure.
  • <YOUR_AZURE_REGION>: The Azure region you'll use. You can use eastus by default, but we recommend that you configure a region closer to where you live. You can see the full list of available regions by entering az account list-locations.
  • <YOUR_USER_ASSIGNED_MANAGED_IDENTITY_NAME>: The name of your user assigned managed identity server, which should be unique across Azure.

Next, create a resource group:

az group create \
    --name $AZ_RESOURCE_GROUP \
    --location $AZ_LOCATION \
    --output tsv

Create an Azure Database for MySQL instance

Create Azure Database for MySQL Flexible Server instance and set up an admin user

The first thing you create is a managed Azure Database for MySQL Flexible Server instance.

Note

You can read more detailed information about creating MySQL servers in Quickstart: Create an instance of Azure Database for MySQL with the Azure portal.

If you're using Azure CLI, run the following command to make sure it has sufficient permission:

az login --scope https://graph.microsoft.com/.default

Run the following command to create the server:

az mysql flexible-server create \
    --resource-group $AZ_RESOURCE_GROUP \
    --name $AZ_DATABASE_NAME \
    --location $AZ_LOCATION \
    --yes \
    --output tsv

Run the following command to create a user-assigned identity for assigning:

az identity create \
    --resource-group $AZ_RESOURCE_GROUP \
    --name $AZ_USER_IDENTITY_NAME

Important

After creating the user-assigned identity, ask a user with at least the Privileged Role Administrator role to grant the following permissions for this user-assigned managed identity: User.Read.All, GroupMember.Read.All, and Application.Read.ALL. Alternatively, give the user-assigned managed identity the Directory Readers role. For more information, see the Permissions section of Microsoft Entra authentication for Azure Database for MySQL - Flexible Server.

Run the following command to assign the identity to Azure Database for MySQL Flexible Server for creating Microsoft Entra admin:

az mysql flexible-server identity assign \
    --resource-group $AZ_RESOURCE_GROUP \
    --server-name $AZ_DATABASE_NAME \
    --identity $AZ_USER_IDENTITY_NAME

Run the following command to set the Microsoft Entra admin user:

az mysql flexible-server ad-admin create \
    --resource-group $AZ_RESOURCE_GROUP \
    --server-name $AZ_DATABASE_NAME \
    --display-name $CURRENT_USERNAME \
    --object-id $CURRENT_USER_OBJECTID \
    --identity $AZ_USER_IDENTITY_NAME

Important

When setting the administrator, a new user is added to the Azure Database for MySQL Flexible Server instance with full administrator permissions. Only one Microsoft Entra admin can be created per Azure Database for MySQL Flexible Server instance and selection of another one will overwrite the existing Microsoft Entra admin configured for the server.

This command creates a small Azure Database for MySQL Flexible Server instance and sets the Active Directory admin to the signed-in user.

The Azure Database for MySQL Flexible Server instance that you created has an empty database called flexibleserverdb.

Having any issues? Let us know.

Configure a firewall rule for your Azure Database for MySQL Flexible Server instance

Azure Database for MySQL Flexible Server instances are secured by default. They have a firewall that doesn't allow any incoming connection.

You can skip this step if you're using Bash because the flexible-server create command already detected your local IP address and set it on MySQL server.

If you're connecting to your Azure Database for MySQL Flexible Server instance from Windows Subsystem for Linux (WSL) on a Windows computer, you'll need to add the WSL host ID to your firewall. Obtain the IP address of your host machine by running the following command in WSL:

sudo cat /etc/resolv.conf

Copy the IP address following the term nameserver, then use the following command to set an environment variable for the WSL IP Address:

AZ_WSL_IP_ADDRESS=<the-copied-IP-address>

Then, use the following command to open the server's firewall to your WSL-based app:

az mysql flexible-server firewall-rule create \
    --resource-group $AZ_RESOURCE_GROUP \
    --name $AZ_DATABASE_NAME \
    --start-ip-address $AZ_WSL_IP_ADDRESS \
    --end-ip-address $AZ_WSL_IP_ADDRESS \
    --rule-name allowiprange \
    --output tsv

Configure a MySQL database

Create a new database called demo by using the following command:

az mysql flexible-server db create \
    --resource-group $AZ_RESOURCE_GROUP \
    --database-name demo \
    --server-name $AZ_DATABASE_NAME \
    --output tsv

Create a MySQL non-admin user and grant permission

Next, create a non-admin user and grant all permissions on the demo database to it.

Note

You can read more detailed information about creating MySQL users in Create users in Azure Database for MySQL.

Create a SQL script called create_ad_user.sql for creating a non-admin user. Add the following contents and save it locally:

export AZ_MYSQL_AD_NON_ADMIN_USERID=$(az ad signed-in-user show --query id --output tsv)

cat << EOF > create_ad_user.sql
SET aad_auth_validate_oids_in_tenant = OFF;

CREATE AADUSER '$AZ_MYSQL_AD_NON_ADMIN_USERNAME' IDENTIFIED BY '$AZ_MYSQL_AD_NON_ADMIN_USERID';

GRANT ALL PRIVILEGES ON demo.* TO '$AZ_MYSQL_AD_NON_ADMIN_USERNAME'@'%';

FLUSH privileges;

EOF

Then, use the following command to run the SQL script to create the Microsoft Entra non-admin user:

mysql -h $AZ_DATABASE_NAME.mysql.database.azure.com --user $CURRENT_USERNAME --enable-cleartext-plugin --password=$(az account get-access-token --resource-type oss-rdbms --output tsv --query accessToken) < create_ad_user.sql

Now use the following command to remove the temporary SQL script file:

rm create_ad_user.sql

Create a new Java project

Using your favorite IDE, create a new Java project, and add a pom.xml file in its root directory:

<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>

    <properties>
        <java.version>1.8</java.version>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.30</version>
        </dependency>
        <dependency>
            <groupId>com.azure</groupId>
            <artifactId>azure-identity-extensions</artifactId>
            <version>1.0.0</version>
        </dependency>
    </dependencies>
</project>

This file is an Apache Maven file that configures your project to use:

  • Java 8
  • A recent MySQL driver for Java

Prepare a configuration file to connect to Azure Database for MySQL

Run the following script in the project root directory to create a src/main/resources/database.properties file and add configuration details:

mkdir -p src/main/resources && touch src/main/resources/database.properties

cat << EOF > src/main/resources/database.properties
url=jdbc:mysql://${AZ_DATABASE_NAME}.mysql.database.azure.com:3306/demo?sslMode=REQUIRED&serverTimezone=UTC&defaultAuthenticationPlugin=com.azure.identity.extensions.jdbc.mysql.AzureMysqlAuthenticationPlugin&authenticationPlugins=com.azure.identity.extensions.jdbc.mysql.AzureMysqlAuthenticationPlugin
user=${AZ_MYSQL_AD_NON_ADMIN_USERNAME}
EOF

Note

If you are using MysqlConnectionPoolDataSource class as the datasource in your application, please remove "defaultAuthenticationPlugin=com.azure.identity.extensions.jdbc.mysql.AzureMysqlAuthenticationPlugin" in the url.

mkdir -p src/main/resources && touch src/main/resources/database.properties

cat << EOF > src/main/resources/database.properties
url=jdbc:mysql://${AZ_DATABASE_NAME}.mysql.database.azure.com:3306/demo?sslMode=REQUIRED&serverTimezone=UTC&authenticationPlugins=com.azure.identity.extensions.jdbc.mysql.AzureMysqlAuthenticationPlugin
user=${AZ_MYSQL_AD_NON_ADMIN_USERNAME}
EOF

Note

The configuration property url has ?serverTimezone=UTC appended to tell the JDBC driver to use the UTC date format (or Coordinated Universal Time) when connecting to the database. Otherwise, your Java server would not use the same date format as the database, which would result in an error.

Create a SQL file to generate the database schema

You'll use a src/main/resources/schema.sql file in order to create a database schema. Create that file, with the following content:

DROP TABLE IF EXISTS todo;
CREATE TABLE todo (id SERIAL PRIMARY KEY, description VARCHAR(255), details VARCHAR(4096), done BOOLEAN);

Code the application

Connect to the database

Next, add the Java code that will use JDBC to store and retrieve data from your MySQL server.

Create a src/main/java/DemoApplication.java file and add the following contents:

package com.example.demo;

import com.mysql.cj.jdbc.AbandonedConnectionCleanupThread;

import java.sql.*;
import java.util.*;
import java.util.logging.Logger;

public class DemoApplication {

    private static final Logger log;

    static {
        System.setProperty("java.util.logging.SimpleFormatter.format", "[%4$-7s] %5$s %n");
        log =Logger.getLogger(DemoApplication.class.getName());
    }

    public static void main(String[] args) throws Exception {
        log.info("Loading application properties");
        Properties properties = new Properties();
        properties.load(DemoApplication.class.getClassLoader().getResourceAsStream("database.properties"));

        log.info("Connecting to the database");
        Connection connection = DriverManager.getConnection(properties.getProperty("url"), properties);
        log.info("Database connection test: " + connection.getCatalog());

        log.info("Create database schema");
        Scanner scanner = new Scanner(DemoApplication.class.getClassLoader().getResourceAsStream("schema.sql"));
        Statement statement = connection.createStatement();
        while (scanner.hasNextLine()) {
            statement.execute(scanner.nextLine());
        }

        /*
        Todo todo = new Todo(1L, "configuration", "congratulations, you have set up JDBC correctly!", true);
        insertData(todo, connection);
        todo = readData(connection);
        todo.setDetails("congratulations, you have updated data!");
        updateData(todo, connection);
        deleteData(todo, connection);
        */

        log.info("Closing database connection");
        connection.close();
        AbandonedConnectionCleanupThread.uncheckedShutdown();
    }
}

Having any issues? Let us know.

This Java code will use the database.properties and the schema.sql files that you created earlier, in order to connect to the Azure Database for MySQL Flexible Server instance and create a schema that will store your data.

In this file, you can see that we commented methods to insert, read, update and delete data: you'll code those methods in the rest of this article, and you'll be able to uncomment them one after each other.

Note

The database credentials are stored in the user and password properties of the database.properties file. Those credentials are used when executing DriverManager.getConnection(properties.getProperty("url"), properties);, as the properties file is passed as an argument.

Note

The AbandonedConnectionCleanupThread.uncheckedShutdown(); line at the end is a MySQL driver specific command to destroy an internal thread when shutting down the application. It can be safely ignored.

You can now execute this main class with your favorite tool:

  • Using your IDE, you should be able to right-click on the DemoApplication class and execute it.
  • Using Maven, you can run the application by executing: mvn exec:java -Dexec.mainClass="com.example.demo.DemoApplication".

The application should connect to the Azure Database for MySQL Flexible Server instance, create a database schema, and then close the connection, as you should see in the console logs:

[INFO   ] Loading application properties
[INFO   ] Connecting to the database
[INFO   ] Database connection test: demo
[INFO   ] Create database schema
[INFO   ] Closing database connection

Create a domain class

Create a new Todo Java class, next to the DemoApplication class, and add the following code:

package com.example.demo;

public class Todo {

    private Long id;
    private String description;
    private String details;
    private boolean done;

    public Todo() {
    }

    public Todo(Long id, String description, String details, boolean done) {
        this.id = id;
        this.description = description;
        this.details = details;
        this.done = done;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getDetails() {
        return details;
    }

    public void setDetails(String details) {
        this.details = details;
    }

    public boolean isDone() {
        return done;
    }

    public void setDone(boolean done) {
        this.done = done;
    }

    @Override
    public String toString() {
        return "Todo{" +
                "id=" + id +
                ", description='" + description + '\'' +
                ", details='" + details + '\'' +
                ", done=" + done +
                '}';
    }
}

This class is a domain model mapped on the todo table that you created when executing the schema.sql script.

Insert data into Azure Database for MySQL

In the src/main/java/DemoApplication.java file, after the main method, add the following method to insert data into the database:

private static void insertData(Todo todo, Connection connection) throws SQLException {
    log.info("Insert data");
    PreparedStatement insertStatement = connection
            .prepareStatement("INSERT INTO todo (id, description, details, done) VALUES (?, ?, ?, ?);");

    insertStatement.setLong(1, todo.getId());
    insertStatement.setString(2, todo.getDescription());
    insertStatement.setString(3, todo.getDetails());
    insertStatement.setBoolean(4, todo.isDone());
    insertStatement.executeUpdate();
}

You can now uncomment the two following lines in the main method:

Todo todo = new Todo(1L, "configuration", "congratulations, you have set up JDBC correctly!", true);
insertData(todo, connection);

Executing the main class should now produce the following output:

[INFO   ] Loading application properties
[INFO   ] Connecting to the database
[INFO   ] Database connection test: demo
[INFO   ] Create database schema
[INFO   ] Insert data
[INFO   ] Closing database connection

Read data from Azure Database for MySQL

Next, read the data previously inserted to validate that your code works correctly.

In the src/main/java/DemoApplication.java file, after the insertData method, add the following method to read data from the database:

private static Todo readData(Connection connection) throws SQLException {
    log.info("Read data");
    PreparedStatement readStatement = connection.prepareStatement("SELECT * FROM todo;");
    ResultSet resultSet = readStatement.executeQuery();
    if (!resultSet.next()) {
        log.info("There is no data in the database!");
        return null;
    }
    Todo todo = new Todo();
    todo.setId(resultSet.getLong("id"));
    todo.setDescription(resultSet.getString("description"));
    todo.setDetails(resultSet.getString("details"));
    todo.setDone(resultSet.getBoolean("done"));
    log.info("Data read from the database: " + todo.toString());
    return todo;
}

You can now uncomment the following line in the main method:

todo = readData(connection);

Executing the main class should now produce the following output:

[INFO   ] Loading application properties
[INFO   ] Connecting to the database
[INFO   ] Database connection test: demo
[INFO   ] Create database schema
[INFO   ] Insert data
[INFO   ] Read data
[INFO   ] Data read from the database: Todo{id=1, description='configuration', details='congratulations, you have set up JDBC correctly!', done=true}
[INFO   ] Closing database connection

Having any issues? Let us know.

Update data in Azure Database for MySQL Flexible Server

Next, update the data you previously inserted.

Still in the src/main/java/DemoApplication.java file, after the readData method, add the following method to update data inside the database:

private static void updateData(Todo todo, Connection connection) throws SQLException {
    log.info("Update data");
    PreparedStatement updateStatement = connection
            .prepareStatement("UPDATE todo SET description = ?, details = ?, done = ? WHERE id = ?;");

    updateStatement.setString(1, todo.getDescription());
    updateStatement.setString(2, todo.getDetails());
    updateStatement.setBoolean(3, todo.isDone());
    updateStatement.setLong(4, todo.getId());
    updateStatement.executeUpdate();
    readData(connection);
}

You can now uncomment the two following lines in the main method:

todo.setDetails("congratulations, you have updated data!");
updateData(todo, connection);

Executing the main class should now produce the following output:

[INFO   ] Loading application properties
[INFO   ] Connecting to the database
[INFO   ] Database connection test: demo
[INFO   ] Create database schema
[INFO   ] Insert data
[INFO   ] Read data
[INFO   ] Data read from the database: Todo{id=1, description='configuration', details='congratulations, you have set up JDBC correctly!', done=true}
[INFO   ] Update data
[INFO   ] Read data
[INFO   ] Data read from the database: Todo{id=1, description='configuration', details='congratulations, you have updated data!', done=true}
[INFO   ] Closing database connection

Delete data in Azure Database for MySQL Flexible Server

Finally, delete the data you previously inserted.

Still in the src/main/java/DemoApplication.java file, after the updateData method, add the following method to delete data inside the database:

private static void deleteData(Todo todo, Connection connection) throws SQLException {
    log.info("Delete data");
    PreparedStatement deleteStatement = connection.prepareStatement("DELETE FROM todo WHERE id = ?;");
    deleteStatement.setLong(1, todo.getId());
    deleteStatement.executeUpdate();
    readData(connection);
}

You can now uncomment the following line in the main method:

deleteData(todo, connection);

Executing the main class should now produce the following output:

[INFO   ] Loading application properties
[INFO   ] Connecting to the database
[INFO   ] Database connection test: demo
[INFO   ] Create database schema
[INFO   ] Insert data
[INFO   ] Read data
[INFO   ] Data read from the database: Todo{id=1, description='configuration', details='congratulations, you have set up JDBC correctly!', done=true}
[INFO   ] Update data
[INFO   ] Read data
[INFO   ] Data read from the database: Todo{id=1, description='configuration', details='congratulations, you have updated data!', done=true}
[INFO   ] Delete data
[INFO   ] Read data
[INFO   ] There is no data in the database!
[INFO   ] Closing database connection

Clean up resources

Congratulations! You've created a Java application that uses JDBC to store and retrieve data from Azure Database for MySQL Flexible Server.

To clean up all resources used during this quickstart, delete the resource group using the following command:

az group delete \
    --name $AZ_RESOURCE_GROUP \
    --yes

Next step

Migrate your MySQL database to Azure Database for MySQL using dump and restore