带有传统数据库的JDBC Kafka连接器

Question

我正在尝试将kafka-jdbc连接器（源代码和接收器）与非常旧的数据库（cloudscape）一起使用。我有这个数据库的 JDBC 驱动程序。我将驱动程序放在Confluent（版本5）的“/share/java/kafka/connect/jdbc”文件夹中，并创建了属性文件。

name=test-source-cloud-jdbc-autoincrement
connector.class=io.confluent.connect.jdbc.JdbcSourceConnector
tasks.max=1
connection.url=jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB
mode=incrementing
incrementing.column.name=id
topic.prefix=test-cloud-jdbc-

启动连接器时，日志如下：

[2019-01-31 11:23:36,582] DEBUG Finding best dialect for JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:119)
[2019-01-31 11:23:36,582] DEBUG Dialect Db2DatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,582] DEBUG Dialect DerbyDatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,582] DEBUG Dialect GenericDatabaseDialect scored 10 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,582] DEBUG Dialect MySqlDatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,582] DEBUG Dialect OracleDatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,582] DEBUG Dialect PostgreSqlDatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,583] DEBUG Dialect SapHanaDatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,583] DEBUG Dialect SqlServerDatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,583] DEBUG Dialect SqliteDatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,583] DEBUG Dialect SybaseDatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,583] DEBUG Dialect VerticaDatabaseDialect scored 0 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:126)
[2019-01-31 11:23:36,583] DEBUG Using dialect GenericDatabaseDialect with score 10 against JDBC subprotocol 'cloudscape' and source 'jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB' (io.confluent.connect.jdbc.dialect.DatabaseDialects:132)
[2019-01-31 11:23:36,587] ERROR Failed to create job for ./etc/kafka-connect-jdbc/CloudscapeProperties.properties (org.apache.kafka.connect.cli.ConnectStandalone:102)
[2019-01-31 11:23:36,588] ERROR Stopping after connector error (org.apache.kafka.connect.cli.ConnectStandalone:113)
java.util.concurrent.ExecutionException: org.apache.kafka.connect.runtime.rest.errors.BadRequestException: Connector configuration is invalid and contains the following 2 error(s):
Invalid value java.sql.SQLException: No suitable driver found for jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB for configuration Couldn't open connection to jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB
Invalid value java.sql.SQLException: No suitable driver found for jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB for configuration Couldn't open connection to jdbc:cloudscape:rmi://localhost:1099/CloudscapeDB
You can also find the above list of errors at the endpoint `/{connectorType}/config/validate`
    at org.apache.kafka.connect.util.ConvertingFutureCallback.result(ConvertingFutureCallback.java:79)
    at org.apache.kafka.connect.util.ConvertingFutureCallback.get(ConvertingFutureCallback.java:66)
    at org.apache.kafka.connect.cli.ConnectStandalone.main(ConnectStandalone.java:110)

我想JDBC驱动程序很旧（它使用JAVA1.3）这一事实存在问题。驱动程序使用RMI协议进行通信。如果我运行一个非常简单的JAVA RMI客户端来使用RmiJdbc查询数据库。jar和cloudscape。jar（驱动程序），我能够查询DB并获得结果。

你认为是与Java版本有关的问题吗？而且，是否有意义/是否可以实现自定义 Kafka 驱动程序来从此数据库读取数据？关于此问题或如何为旧数据库实现自定义 Kafka 驱动程序的任何建议？

Answer 1

您可以更改META-INF/services/java.sql。驱动程序，更改它，用驱动程序类重写它。它可以为我工作！

Answer 2

我不会马上得出驱动程序/数据库过时的结论...

您不能指向＜code＞插件。path直接指向JDBC驱动程序。

将< code>plugin.path更新为顶级< code >/path/to/confluent-x . y . z/usr/share/Java 的绝对路径，并将您的驱动程序复制到< code>kafka-connect-jdbc文件夹中。

重启Connect，然后应该找到驱动程序。

您可以通过查找kafka/connect-log4j.properties并设置来进一步调试

log4j.rootLogger=DEBUG, stdout

然后你会看到这样的日志(MySQL的例子)

[2019-01-15 09:45:26,949] DEBUG Registered java.sql.Driver: com.mysql.cj.jdbc.Driver@37303f12 to java.sql.DriverManager (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:277)