我正在使用HikariCP运行SQLite数据库。我的配置如下所示:
public class SQLiteDataSource {
private static final HikariConfig config = new HikariConfig();
private static final HikariDataSource ds;
static {
config.setJdbcUrl("jdbc:sqlite:database.db");
config.setConnectionTestQuery("SELECT 1");
config.addDataSourceProperty("cachePrepStmts", true);
config.addDataSourceProperty("prepStmtCacheSize", "250");
config.addDataSourceProperty("prepStmtCacheSwlLimit", "2048");
config.setIdleTimeout(10000);
config.setMaxLifetime(30000);
config.setValidationTimeout(30000);
config.setMaximumPoolSize(100);
config.setMinimumIdle(10);
config.setAllowPoolSuspension(false);
ds = new HikariDataSource(config);
}
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
}
getConnection()
方法用于从数据库中的表获取数据。这些函数如下所示:
// This is a slightly abreviated function to get a boolean from a table in the database where the primary key "id" matches the one requested
public static Boolean getBoolean(String Id, String column) {
try (final PreparedStatement preparedStatement = SQLiteDataSource.getConnection()
// language=SQLite
.prepareStatement("SELECT " + column + " FROM table WHERE id = ?")) {
preparedStatement.setString(1, Id);
try (final ResultSet resultSet = preparedStatement.executeQuery()) {
if (resultSet.next()) {
Boolean bool = resultSet.getBoolean(setting);
resultSet.close();
preparedStatement.getConnection().close();
return bool;
}
}
preparedStatement.getConnection().close();
} catch (SQLException e) {
e.printStackTrace();
}
return false;
}
每次调用该函数时,PreparedStatement的连接都会在最后关闭。但是,池大小会不断增长,直到达到最大池大小并超时为止。
有没有办法我可以防止这种情况或强制关闭连接?
按照@Nithin的建议删除preparedStatement.getConnection().close()
,并在try-with-resources块中明确获取连接:
try (Connection con = SQLiteDataSource.getConnection();final PreparedStatement preparedStatement = con
// language=SQLite
.prepareStatement("SELECT " + column + " FROM table WHERE id = ?")) {
那样,连接也会在块末尾关闭
您正在泄漏连接,因为您没有在try-with-resources块中保留引用。因此,您用于创建语句的连接永远不会关闭。相反,您获得了一个[[different连接并将其关闭(在两个不同的位置!)。最终,您将以这种方式耗尽连接池。
此外,鉴于您正在使用try-with-resources,因此无需显式关闭resultSet
。您需要将代码更改为:
try (Connection connection = SQLiteDataSource.getConnection();
PreparedStatement preparedStatement = connection
.prepareStatement("SELECT " + column + " FROM table WHERE id = ?")) {
preparedStatement.setString(1, Id);
try (ResultSet resultSet = preparedStatement.executeQuery()) {
if (resultSet.next()) {
Boolean bool = resultSet.getBoolean(setting);
return bool;
}
}
} catch (SQLException e) {
e.printStackTrace();
}
还请注意,如果column
的值来自不受信任的来源,则容易受到SQL注入的攻击。