Menjalankan kueri menggunakan driver JDBC

Halaman ini berisi contoh yang menunjukkan kepada Anda cara menjalankan kueri menggunakan Driver Databricks JDBC, versi 3 ke atas.

Nota

Driver Databricks JDBC memiliki batas parameter 256 untuk pernyataan berparameter.

Contoh: Menjalankan kueri

Contoh berikut menunjukkan cara menggunakan Driver Databricks JDBC untuk menjalankan kueri Databricks SQL menggunakan sumber daya komputasi Azure Databricks.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
import java.util.Properties;

public class DatabricksJDBCExample {

    public static void main(String[] args) {

        Class.forName("com.databricks.client.jdbc.Driver");

        // Set JDBC URL properties
        String jdbcUrl = "jdbc:databricks://dbc-a1b2345c-d6e7.cloud.databricks.com:443";
        Properties connectionProperties = new Properties();
        connectionProperties.put("httpPath", "sql/protocolv1/o/123456780012345/0123-123450-z000pi22");
        connectionProperties.put("ssl", "1");

        // Set authentication properties (personal access token)
        connectionProperties.put("AuthMech", "3");
        connectionProperties.put("user", "token");
        connectionProperties.put("password", "12345678901234667890abcdabcd");

        // Set logging properties
        connectionProperties.put("logPath", "logs/myapplication.log");

        // Establish connection and execute query
        try (Connection connection = DriverManager.getConnection(jdbcUrl, connectionProperties);
             Statement statement = connection.createStatement();
             ResultSet resultSet = statement.executeQuery("SELECT * FROM samples.nyctaxi.trips")) {

            // Get metadata and column names
            ResultSetMetaData metaData = resultSet.getMetaData();
            String[] columns = new String[metaData.getColumnCount()];
            for (int i = 0; i < columns.length; i++) {
                columns[i] = metaData.getColumnName(i + 1);
            }

            // Process and print the result set
            while (resultSet.next()) {
                System.out.print("Row " + resultSet.getRow() + "=[");
                for (int i = 0; i < columns.length; i++) {
                    if (i != 0) {
                        System.out.print(", ");
                    }
                    System.out.print(columns[i] + "='" + resultSet.getObject(i + 1) + "'");
                }
                System.out.println("]");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Contoh: Menjalankan kueri secara asinkron

Contoh berikut menunjukkan cara menggunakan Driver Databricks JDBC untuk menjalankan dan menangani kueri Databricks SQL asinkron.

Untuk referensi API, lihat Referensi Java API untuk Driver JDBC Databricks.

Mulai eksekusi asinkron dari pernyataan:

Statement statement = conn.createStatement();
IDatabricksStatement dbStatement = statement.unwrap(IDatabricksStatement.class);

ResultSet result = dbStatement.executeAsync(sql);
IDatabricksResultSet asyncResult = result.unwrap(IDatabricksResultSet.class);
IExecutionStatus asyncStatus = asyncResult.getExecutionStatus();
long startTime = System.currentTimeMillis();
while ((asyncStatus.getExecutionState() == ExecutionState.RUNNING |  asyncStatus.getExecutionState() == ExecutionState.PENDING) || (startTime + timeout < System.currentTimeMillis())) {
  Thread.sleep(1000); // Sleep for 1000 ms
  asyncResult = dbStatement.getExecutionResult().unwrap(IDatabricksResultSet.class);
  asyncStatus = asyncResult.getExecutionStatus();
}

if (asyncStatus.getExecutionStatus() == ExecutionState.RUNNING | ExecutionState.PENDING) {
  dbStatement.cancel();
}

if (asyncStatus.getExecutionStatus() == ExecutionState.SUCCEEDED) {
  // process result set
}

if (asyncStatus.getExecutionStatus() == ExecutionState.FAILED) {
  String sqlState = asyncStatus.getSqlState();
  String errorMessage = asyncStatus.getErrorMessage();
  // log error code and message
}

Kelola pernyataan dalam utas terpisah:

Statement statement = conn1.createStatement();
IDatabricksStatement dbStatement = statement.unwrap(IDatabricksStatement.class);

ResultSet asyncResult = dbStatement.executeAsync(sql);
IDatabricksResultSet drs = asyncResult.unwrap(IDatabricksResultSet.class);
String statementId = drs.getStatementId();

ExecutionState state = drs.getExecutionStatus().getExecutionState();

while (state != ExecutionState.SUCCEEDED) {
  Thread.sleep(sleepInterval);
  asyncResult = dbStatement.getExecutionResult();
  state = asyncResult.unwrap(IDatabricksResultSet.class).getExecutionStatus().getExecutionState();
}


// In another thread
IDatabricksConnection dbConn2 = conn2.unwrap(IDatabricksConnection.class);
IDatabricksStatement asyncStatementHandle = dbConn2.getStatement(statementId).unwrap(IDatabricksStatement.class);
IDatabricksResultSet asyncResultHandle = asyncStatementHandle.getExecutionResult().unwrap(IDatabricksResultSet.class);

// Cancel if needed
if (asyncResultHandle.getExecutionStatus().getExecutionState() == ExecutionState.PENDING | asyncResultHandle.getExecutionStatus().getExecutionState() == ExecutionState.RUNNING) {
  asyncStatementHandle.cancel();
}

Tutup koneksi menggunakan ID koneksi:

// Get connection-Id from existing connection
String connectionId = conn.unwrap(IDatabricksConnection.class).getConnectionId();

// Close the connection from other thread using same JDBC Url and connection properties and connection-Id retrieved from above
com.databricks.client.jdbc.Driver.getInstance().closeConnection(jdbcUrl, properties, connectionId);

Contoh: Mengkueri data geospasial

Contoh berikut menunjukkan cara mengkueri dan mengambil jenis data geospasial menggunakan Driver Databricks JDBC. Untuk mengambil data geospasial sebagai objek Java terstruktur, aktifkan EnableComplexDatatypeSupport properti koneksi dan EnableGeoSpatialSupport .

Untuk informasi selengkapnya tentang jenis dan fungsi data geospasial, lihat Fungsi geospasial ST.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
import java.util.Properties;
import com.databricks.jdbc.api.IGeometry;
import com.databricks.jdbc.api.IGeography;

public class GeospatialExample {

    public static void main(String[] args) {

        // Set JDBC URL properties
        String jdbcUrl = "jdbc:databricks://dbc-a1b2345c-d6e7.cloud.databricks.com:443";
        Properties connectionProperties = new Properties();
        connectionProperties.put("httpPath", "sql/protocolv1/o/123456780012345/0123-123450-z000pi22");
        connectionProperties.put("ssl", "1");

        // Set authentication properties (personal access token)
        connectionProperties.put("AuthMech", "3");
        connectionProperties.put("user", "token");
        connectionProperties.put("password", "12345678901234667890abcdabcd");

        // Enable geospatial support
        connectionProperties.put("EnableComplexDatatypeSupport", "1");
        connectionProperties.put("EnableGeoSpatialSupport", "1");

        // Establish connection and execute geospatial query
        try (Connection connection = DriverManager.getConnection(jdbcUrl, connectionProperties);
             Statement statement = connection.createStatement();
             ResultSet rs = statement.executeQuery(
                 "SELECT ST_Point(1.0, 2.0) as point, " +
                 "ST_GeogFromText('POINT(-122.4194 37.7749)') as location")) {

            while (rs.next()) {
                // Retrieve GEOMETRY object
                IGeometry point = (IGeometry) rs.getObject("point");
                System.out.println("Point WKT: " + point.getWKT());
                System.out.println("Point SRID: " + point.getSRID());

                // Retrieve GEOGRAPHY object
                IGeography location = (IGeography) rs.getObject("location");
                System.out.println("Location WKT: " + location.getWKT());
                System.out.println("Location SRID: " + location.getSRID());

                // Metadata
                ResultSetMetaData meta = rs.getMetaData();
                System.out.println("Column 1 type: " + meta.getColumnTypeName(1)); // GEOMETRY
                System.out.println("Column 1 class: " + meta.getColumnClassName(1)); // com.databricks.jdbc.api.IGeometry
                System.out.println("Column 2 type: " + meta.getColumnTypeName(2)); // GEOGRAPHY
                System.out.println("Column 2 class: " + meta.getColumnClassName(2)); // com.databricks.jdbc.api.IGeography
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}