Question

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Unit测试（TestNG和Junit）获取连接时 - 在DataSource初始化时获得异常。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

我能想到的唯一事情就是用classpath / classloader搞砸了。

Answer 1

问题是由于我在类路径中使用了Postgres JDBC驱动程序。 Redshift JDBC驱动程序实际上是Postgres JDBC驱动程序，带有一些额外的类，可能还有一些重构。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，这解决了这个问题。

Redshift JDBC41驱动程序初始化异常

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