Lindorm:Use Druid to develop applications

Step 1: Configure the connection pool

In src/main/resources, create druid.properties with the following content. Parameters are grouped into three categories:

• Replace with your values — required before the application can connect

• Tune for your workload — adjust based on your concurrency and hardware

• Keep as-is — defaults are optimized for LindormTable; changing them may cause errors

# ── Replace with your values ─────────────────────────────────────────────────
# Driver class name — do not change this value.
driverClassName=com.aliyun.lindorm.table.client.Driver

# Endpoint for LindormTable. Get the value from the Lindorm console.
# See: https://www.alibabacloud.com/help/en/lindorm/user-guide/connect-to-an-apsaradb-for-lindorm-instance#section-xi3-1q0-gv0
url=jdbc:lindorm:table:url=http://ld-bp17j28j2y7pm****.lindorm.rds.aliyuncs.com:30060

# Username and password for LindormTable.
# View or reset credentials in the LindormTable cluster management system.
# See: https://www.alibabacloud.com/help/en/doc-detail/174671.html#topic2090
# To change your password, see: https://www.alibabacloud.com/help/en/doc-detail/174671.html#section-n3z-64v-v73
username=****
password=****

# Target database to connect to.
connectionProperties=database=****

# ── Tune for your workload ────────────────────────────────────────────────────
# Number of connections created at startup.
initialSize=10

# Minimum number of idle connections.
# For high-throughput scenarios, set this equal to maxActive.
# For workloads with significant traffic spikes, use a smaller value.
minIdle=40

# Maximum number of active connections.
# Set this to match your thread pool size.
maxActive=40

# Maximum usage count per connection before it is recycled.
# Recycling connections periodically prevents load imbalance across LDServer nodes.
druid.phyMaxUseCount=10000

# ── Keep as-is ────────────────────────────────────────────────────────────────
# Initialize the pool on startup.
init=true

# Maximum wait time (ms) to acquire a connection from the pool.
maxWait=30000

# Connection keep-alive settings.
# Changing these may cause unexpected disconnections (ConnectionDisconnectedException).
druid.keepAlive=true
druid.keepAliveBetweenTimeMillis=30000
minEvictableIdleTimeMillis=300000
maxEvictableIdleTimeMillis=600000
timeBetweenEvictionRunsMillis=5000

# Maximum connection lifetime (ms) before recycling.
# Together with phyMaxUseCount, this periodically refreshes connections
# to prevent uneven distribution across frontend nodes.
phyTimeoutMillis=1800000

# Connection validation settings.
validationQuery=SELECT 1
testWhileIdle=true
testOnBorrow=false
testOnReturn=false

# Prepared statement cache — disabled to avoid NoSuchStatement errors.
poolPreparedStatements=false
maxOpenPreparedStatements=-1
druid.maxPoolPreparedStatementPerConnectionSize=-1

For the full list of Druid configuration parameters, see DruidDataSource configuration.

Step 2: Initialize the connection pool

Load druid.properties and create the DataSource:

// Load configuration from druid.properties
Properties properties = new Properties();
InputStream inputStream = DruidPoolDemo.class.getClassLoader().getResourceAsStream("druid.properties");
properties.load(inputStream);

// Initialize the connection pool
DataSource dataSource = DruidDataSourceFactory.createDataSource(properties);

Step 3: Run CRUD operations

All examples below acquire a connection from the pool with dataSource.getConnection() and return it via try-with-resources. Use PreparedStatement for parameterized queries to prevent SQL injection.

Create a table

String tableName = "sql_table_" + new Random().nextInt(1000);

try (Connection connection = dataSource.getConnection()) {
    try (Statement statement = connection.createStatement()) {
        String sql = "create table if not exists " + tableName
                   + "(id VARCHAR, name VARCHAR, primary key(id))";
        int ret = statement.executeUpdate(sql);
        System.out.println(ret);
    }
}

Insert data

try (Connection connection = dataSource.getConnection()) {
    String sql = "upsert into " + tableName + "(id,name) values(?,?)";
    try (PreparedStatement ps = connection.prepareStatement(sql)) {
        ps.setString(1, "aa");
        ps.setString(2, "bb");
        int ret = ps.executeUpdate();
        System.out.println(ret);
    }
}

Query data

try (Connection connection = dataSource.getConnection()) {
    String sql = "select * from " + tableName + " where id=?";
    try (PreparedStatement ps = connection.prepareStatement(sql)) {
        ps.setString(1, "aa");
        ResultSet rs = ps.executeQuery();
        while (rs.next()) {
            String id = rs.getString(1);
            String name = rs.getString(2);
            System.out.println("id=" + id);
            System.out.println("name=" + name);
        }
    }
}

Delete data

try (Connection connection = dataSource.getConnection()) {
    String sql = "delete from " + tableName + " where id=?";
    try (PreparedStatement ps = connection.prepareStatement(sql)) {
        ps.setString(1, "aa");
        ps.executeUpdate();
    }
}