Connect JDBC to a GoogleSQL-dialect database

This page shows you how to perform basic operations in Cloud Spanner using the Spanner JDBC driver.

Install the JDBC driver

Follow the steps in Spanner client libraries to set up authentication, and then add the Spanner JDBC driver dependencies, shown in the following snippet, to your pom.xml file.

spanner/jdbc/pom.xml 
<dependencies>
  <!-- The Spanner JDBC driver dependency -->
  <dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>google-cloud-spanner-jdbc</artifactId>
  </dependency>
  <!--CSV parsing dependencies -->
  <dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-csv</artifactId>
    <version>1.10.0</version>
  </dependency>
  <dependency>
    <groupId>commons-cli</groupId>
    <artifactId>commons-cli</artifactId>
    <version>1.5.0</version>
  </dependency>

  <!-- Test dependencies -->
  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13.2</version>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>com.google.truth</groupId>
    <artifactId>truth</artifactId>
    <version>1.1.4</version>
    <scope>test</scope>
  </dependency>
</dependencies>
In case you are using a framework that requires the Java class name in order to load the JDBC driver, it is com.google.cloud.spanner.jdbc.JdbcDriver. See the API documentation for JdbcDriver for how to set up a connection.

Connect to a Cloud Spanner database

The JdbcDriver class description shows the connection string syntax and includes sample code to create a connection and run a query.

The driver automatically detects the SQL dialect (GoogleSQL or PostgreSQL) of the specified database. A dialect parameter is not required or allowed.

Connect to the emulator

To connect to the emulator, set the SPANNER_EMULATOR_HOST environment variable, for example:

Linux / macOS

export SPANNER_EMULATOR_HOST=localhost:9010

Windows

set SPANNER_EMULATOR_HOST=localhost:9010

This instructs the Spanner JDBC driver driver to connect to the emulator running on the localhost instead of the default production service.

Examples

The following code examples cover some common use cases.

Run a schema update

The following code example adds the Singers table to the database by first creating a JDBC connection and then creating the table:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

class CreateTableExample {

  static void createTable() throws SQLException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";
    createTable(projectId, instanceId, databaseId);
  }

  static void createTable(String projectId, String instanceId, String databaseId)
      throws SQLException {
    String connectionUrl =
        String.format(
            "jdbc:cloudspanner:/projects/%s/instances/%s/databases/%s",
            projectId, instanceId, databaseId);
    try (Connection connection = DriverManager.getConnection(connectionUrl)) {
      try (Statement statement = connection.createStatement()) {
        statement.execute(
            "CREATE TABLE Singers (\n"
                + "  SingerId   INT64 NOT NULL,\n"
                + "  FirstName  STRING(1024),\n"
                + "  LastName   STRING(1024),\n"
                + "  SingerInfo BYTES(MAX),\n"
                + "  Revenues   NUMERIC,\n"
                + ") PRIMARY KEY (SingerId)\n");
      }
    }
    System.out.println("Created table [Singers]");
  }
}

Use a transaction in autocommit mode to add rows

If you don't need to commit multiple operations as a group, you can use a transaction in autocommit mode, which is the default behavior. The following code example uses a transaction in autocommit mode to add rows to the Singers table:

import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Types;
import java.util.Arrays;
import java.util.List;

class InsertDataExample {
  // Class to contain singer sample data.
  static class Singer {
    final long singerId;
    final String firstName;
    final String lastName;
    final BigDecimal revenues;

    Singer(long singerId, String firstName, String lastName, BigDecimal revenues) {
      this.singerId = singerId;
      this.firstName = firstName;
      this.lastName = lastName;
      this.revenues = revenues;
    }
  }

  static final List<Singer> SINGERS =
      Arrays.asList(
          new Singer(10, "Marc", "Richards", new BigDecimal("104100.00")),
          new Singer(20, "Catalina", "Smith", new BigDecimal("9880.99")),
          new Singer(30, "Alice", "Trentor", new BigDecimal("300183")),
          new Singer(40, "Lea", "Martin", new BigDecimal("20118.12")),
          new Singer(50, "David", "Lomond", new BigDecimal("311399.26")));

  static void insertData() throws SQLException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";
    insertData(projectId, instanceId, databaseId);
  }

  static void insertData(String projectId, String instanceId, String databaseId)
      throws SQLException {
    String connectionUrl =
        String.format(
            "jdbc:cloudspanner:/projects/%s/instances/%s/databases/%s",
            projectId, instanceId, databaseId);
    try (Connection connection = DriverManager.getConnection(connectionUrl)) {
      try (PreparedStatement ps =
          connection.prepareStatement(
              "INSERT INTO Singers\n"
                  + "(SingerId, FirstName, LastName, SingerInfo, Revenues)\n"
                  + "VALUES\n"
                  + "(?, ?, ?, ?, ?)")) {
        for (Singer singer : SINGERS) {
          ps.setLong(1, singer.singerId);
          ps.setString(2, singer.firstName);
          ps.setString(3, singer.lastName);
          ps.setNull(4, Types.BINARY);
          ps.setBigDecimal(5, singer.revenues);
          ps.addBatch();
        }
        int[] updateCounts = ps.executeBatch();
        System.out.printf("Insert counts: %s%n", Arrays.toString(updateCounts));
      }
    }
  }
}

Control how multiple operations are committed as a group

If you want to control whether Spanner commits multiple operations together as a group, you can disable autocommit mode. The following code example uses connection.setAutoCommit(false) and connection.commit() to add rows to the Singers table.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Arrays;

class BatchDmlExample {

  static void batchDml() throws SQLException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";
    batchDml(projectId, instanceId, databaseId);
  }

  static void batchDml(String projectId, String instanceId, String databaseId) throws SQLException {
    String connectionUrl =
        String.format(
            "jdbc:cloudspanner:/projects/%s/instances/%s/databases/%s",
            projectId, instanceId, databaseId);
    try (Connection connection = DriverManager.getConnection(connectionUrl)) {
      connection.setAutoCommit(false);
      try (Statement statement = connection.createStatement()) {
        statement.addBatch(
            "INSERT INTO Singers (SingerId, FirstName, LastName, Revenues)\n"
                + "VALUES (10, 'Marc', 'Richards', 100000)");
        statement.addBatch(
            "INSERT INTO Singers (SingerId, FirstName, LastName, Revenues)\n"
                + "VALUES (11, 'Amirah', 'Finney', 195944.10)");
        statement.addBatch(
            "INSERT INTO Singers (SingerId, FirstName, LastName, Revenues)\n"
                + "VALUES (12, 'Reece', 'Dunn', 10449.90)");
        int[] updateCounts = statement.executeBatch();
        connection.commit();
        System.out.printf("Batch insert counts: %s%n", Arrays.toString(updateCounts));
      }
    }
  }
}

Run a SQL query

The following code example returns all rows in the Singers table ordered by the singer's last name:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class SingleUseReadOnlyExample {

  static void singleUseReadOnly() throws SQLException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";
    singleUseReadOnly(projectId, instanceId, databaseId);
  }

  static void singleUseReadOnly(String projectId, String instanceId, String databaseId)
      throws SQLException {
    String connectionUrl =
        String.format(
            "jdbc:cloudspanner:/projects/%s/instances/%s/databases/%s",
            projectId, instanceId, databaseId);
    try (Connection connection = DriverManager.getConnection(connectionUrl);
        Statement statement = connection.createStatement()) {
      // When the connection is in autocommit mode, any query that is executed will automatically
      // be executed using a single-use read-only transaction, even if the connection itself is in
      // read/write mode.
      try (ResultSet rs =
          statement.executeQuery(
              "SELECT SingerId, FirstName, LastName, Revenues FROM Singers ORDER BY LastName")) {
        while (rs.next()) {
          System.out.printf(
              "%d %s %s %s%n",
              rs.getLong(1), rs.getString(2), rs.getString(3), rs.getBigDecimal(4));
        }
      }
    }
  }
}

What's next