Redshift JDBC41 驱动程序初始化异常答案

【问题标题】：Redshift JDBC41 driver init exceptionRedshift JDBC41 驱动程序初始化异常
【发布时间】：2015-09-09 18:14:06
【问题描述】：

我正在开发通过 Redshift JDBC41 驱动程序版本 1.1.2.0002 连接到 AWS Redshift 实例的应用程序

当我使用 main(.) 方法运行应用程序时一切正常，但是当我尝试从单元测试（TestNG 和 Junit）获取连接时 - 在 DataSource 初始化时出现异常。这是 Redshift 客户端类：

import com.amazon.redshift.jdbc41.DataSource;
import com.mycompany.common.config.PropertiesHelper;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

/**
*/
public class RedshiftDBClient {

private static final Logger logger = LogManager.getLogger(RedshiftDBClient.class);

private static RedshiftDBClient instance;

private DataSource dataSource;

private Properties properties;

private RedshiftDBClient() {
}

private void initDataSource() throws IOException {


    properties = PropertiesHelper.getProperties();

    dataSource = new DataSource();
    dataSource.setUserID(properties.getProperty("rs.db.username"));
    dataSource.setPassword(properties.getProperty("rs.db.password"));
    dataSource.setURL(properties.getProperty("rs.db.url"));
}

public static synchronized RedshiftDBClient getInstance() {

    if (instance == null) {
        instance = new RedshiftDBClient();
    }

    return instance;
}

private DataSource getDataSource() throws IOException {

    if (dataSource == null) {
        initDataSource();
    }

    return  dataSource;
}

public Connection getConnection() throws SQLException, IOException {
    return getDataSource().getConnection();
}
}

这是我得到的错误：

    java.lang.ClassCastException: com.amazon.redshift.jdbc41.Driver cannot be cast to com.amazon.dsi.core.interfaces.IDriver
    at com.amazon.dsi.core.impl.DSIDriverFactory.createDriver(Unknown Source)
    at com.amazon.jdbc.common.AbstractDataSource.doInitialize(Unknown Source)
    at com.amazon.jdbc.common.AbstractDataSource.getSimbaConnection(Unknown Source)
    at com.amazon.jdbc.common.AbstractDataSource.getConnection(Unknown Source)
    at com.mycompany.util.RedshiftDBClient.getConnection(RedshiftDBClient.java:60)
    at com.mycompany.model.redshift.MatchSummaryModel.save(MatchSummaryModel.java:37)
    at com.mycompany.thrift_gen.matchmaking.MatchmakingServiceHandler.ReportMatchResults(MatchmakingServiceHandler.java:59)
    at com.mycompany.thrift_gen.matchmaking.MatchmakingClientProxy$Processor$ReportMatchResults.getResult(MatchmakingClientProxy.java:499)
    at com.mycompany.thrift_gen.matchmaking.MatchmakingClientProxy$Processor$ReportMatchResults.getResult(MatchmakingClientProxy.java:484)
    at org.apache.thrift.ProcessFunction.process(ProcessFunction.java:39)
    at org.apache.thrift.TBaseProcessor.process(TBaseProcessor.java:39)
    at org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:285)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
11:23:55.276 [pool-2-thread-1] ERROR com.mycompany.thrift_gen.matchmaking.MatchmakingServiceHandler - Database exception
java.sql.SQLException: Error creating Driver, Driver class name incorrect.
    at com.amazon.jdbc.common.AbstractDataSource.doInitialize(Unknown Source) ~[RedshiftJDBC41-1.1.2.0002.jar:RedshiftJDBC_1.1.2.0002]
    at com.amazon.jdbc.common.AbstractDataSource.getSimbaConnection(Unknown Source) ~[RedshiftJDBC41-1.1.2.0002.jar:RedshiftJDBC_1.1.2.0002]
    at com.amazon.jdbc.common.AbstractDataSource.getConnection(Unknown Source) ~[RedshiftJDBC41-1.1.2.0002.jar:RedshiftJDBC_1.1.2.0002]
    at com.mycompany.util.RedshiftDBClient.getConnection(RedshiftDBClient.java:60) ~[classes/:?]
    at com.mycompany.model.redshift.MatchSummaryModel.save(MatchSummaryModel.java:37) ~[classes/:?]
    at com.mycompany.thrift_gen.matchmaking.MatchmakingServiceHandler.ReportMatchResults(MatchmakingServiceHandler.java:59) [classes/:?]
    at com.mycompany.thrift_gen.matchmaking.MatchmakingClientProxy$Processor$ReportMatchResults.getResult(MatchmakingClientProxy.java:499) [classes/:?]
    at com.mycompany.thrift_gen.matchmaking.MatchmakingClientProxy$Processor$ReportMatchResults.getResult(MatchmakingClientProxy.java:484) [classes/:?]
    at org.apache.thrift.ProcessFunction.process(ProcessFunction.java:39) [libthrift-0.9.2.jar:0.9.2]
    at org.apache.thrift.TBaseProcessor.process(TBaseProcessor.java:39) [libthrift-0.9.2.jar:0.9.2]
    at org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:285) [libthrift-0.9.2.jar:0.9.2]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_45]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_45]
    at java.lang.Thread.run(Thread.java:745) [?:1.8.0_45]
Caused by: com.amazon.support.exceptions.GeneralException: Error creating Driver, Driver class name incorrect.
    at com.amazon.dsi.core.impl.DSIDriverFactory.createDriver(Unknown Source) ~[RedshiftJDBC41-1.1.2.0002.jar:RedshiftJDBC_1.1.2.0002]
    ... 14 more

我唯一能想到的就是类路径/类加载器搞砸了。

【问题讨论】：

标签： java jdbc amazon-redshift

【解决方案1】：

问题是因为我在类路径中有 Postgres JDBC 驱动程序。 Redshift JDBC 驱动程序实际上是带有一些附加类的 Postgres JDBC 驱动程序，并且可能进行了一些重构。我已经删除了 Redshift 驱动程序并使用 Postgres 驱动程序来访问这两个数据库，从而解决了这个问题。

【讨论】：