本页面介绍了如何使用 Spanner JDBC 驱动程序在 Spanner 中执行基本操作。
安装 JDBC 驱动程序
按照 Spanner 客户端库中的步骤设置身份验证，然后将 Spanner JDBC 驱动程序依赖项（如以下代码段所示）添加到 pom.xml 文件中。
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.google.cloud</groupId>
<artifactId>libraries-bom</artifactId>
<version>26.37.0</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>com.google.cloud</groupId>
<artifactId>google-cloud-spanner-jdbc</artifactId>
</dependency>com.google.cloud.spanner.jdbc.JdbcDriver。 如需了解如何设置连接，请参阅 JdbcDriver 的 API 文档。
连接到 Spanner 数据库
JdbcDriver 类说明显示了连接字符串语法，并添加了用于创建连接和运行查询的示例代码。
该驱动程序会自动检测指定数据库的 SQL 方言（GoogleSQL 或 PostgreSQL）。不需要或允许使用方言参数。
连接到模拟器
如需连接到模拟器，请设置 SPANNER_EMULATOR_HOST 环境变量，例如：
Linux/macOS
export SPANNER_EMULATOR_HOST=localhost:9010
Windows
set SPANNER_EMULATOR_HOST=localhost:9010
此命令指示 Spanner JDBC 驱动程序驱动程序连接到在 localhost 上运行的模拟器，而不是连接到默认的生产服务。
示例
以下代码示例涵盖了一些常见的使用场景。
运行架构更新
以下代码示例通过首先创建 JDBC 连接，然后创建表来将 Singers 表添加到数据库：
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]");
}
}在自动提交模式下使用事务来添加行
如果您不需要将多个操作作为一个组提交，则可以在自动提交模式下使用事务，这是默认行为。以下代码示例在自动提交模式下使用事务向 Singers 表添加行：
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));
}
}
}
}控制以群组形式提交多项操作的方式
如果您想要控制 Spanner 是否将多项操作作为一个组一起提交，您可以停用自动提交模式。以下代码示例使用 connection.setAutoCommit(false) 和 connection.commit() 向 Singers 表添加行。
import com.google.common.collect.ImmutableList;
import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Arrays;
class BatchDmlExample {
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 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);
}
// This example shows how to execute a batch of DML statements with the JDBC driver.
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);
ImmutableList<Singer> singers = ImmutableList.of(
new Singer(10, "Marc", "Richards", BigDecimal.valueOf(10000)),
new Singer(11, "Amirah", "Finney", BigDecimal.valueOf(195944.10d)),
new Singer(12, "Reece", "Dunn", BigDecimal.valueOf(10449.90))
);
try (Connection connection = DriverManager.getConnection(connectionUrl)) {
connection.setAutoCommit(false);
// Use prepared statements for the lowest possible latency when executing the same SQL string
// multiple times.
try (PreparedStatement statement = connection.prepareStatement(
"INSERT INTO Singers (SingerId, FirstName, LastName, Revenues)\n"
+ "VALUES (?, ?, ?, ?)")) {
for (Singer singer : singers) {
statement.setLong(1, singer.singerId);
statement.setString(2, singer.firstName);
statement.setString(3, singer.lastName);
statement.setBigDecimal(4, singer.revenues);
// Add the current parameter values to the batch.
statement.addBatch();
}
// Execute the batched statements.
int[] updateCounts = statement.executeBatch();
connection.commit();
System.out.printf("Batch insert counts: %s%n", Arrays.toString(updateCounts));
}
}
}
}运行 SQL 查询
以下代码示例返回 Singers 表中的所有行，按歌手的姓氏排序：
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));
}
}
}
}
}