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我使用 CQL 准备了一些带有 cassandra 的表。事实上，我尝试对我的数据应用聚合查询（sum、avg 等）。所以，我在 java 中使用了 presto-cassandra。我已将 presto 配置如下：

配置属性：

coordinator=true
node-scheduler.include-coordinator=true
http-server.http.port=8080
task.max-memory=1GB
discovery-server.enabled=true
discovery.uri= `http://localhost:8080`

JVM.properties：

-server
-Xmx16G
-XX:+UseConcMarkSweepGC
-XX:+ExplicitGCInvokesConcurrent
-XX:+CMSClassUnloadingEnabled
-XX:+AggressiveOpts
-XX:+HeapDumpOnOutOfMemoryError
-XX:OnOutOfMemoryError=kill -9 %p
-XX:PermSize=150M
-XX:MaxPermSize=150M
-XX:ReservedCodeCacheSize=150M
-Xbootclasspath/p:C:/Presto/lib/floatingdecimal-0.1.jar

日志属性：

com.facebook.presto=INFO

节点属性：

node.environment=production
node.id=ffffffff-ffff-ffff-ffff-ffffffffffff
node.data-dir=C:/Presto/data

cassandra.properties：

connector.name=cassandra
cassandra.contact-points=localhost
cassandra.native-protocol-port=9142
cassandra.thrift-port=9160

然后，我一直在尝试连接到 presto 并通过 jdbc 运行一些查询，但我不断收到错误消息。代码是：

public static void connect() throws ClassNotFoundException, SQLException{
    Class.forName("com.facebook.presto.jdbc.PrestoDriver");
    PrestoConnection connection = (PrestoConnection) DriverManager.getConnection("jdbc:presto://localhost:8080/cassandra/premierkeys", "test","");
    PrestoStatement statement = (PrestoStatement) connection.createStatement();
    ResultSet rs = statement.executeQuery("select * from client");
    while(rs.next()) {
        System.out.println(rs.getString(1));
    }       
}
public static void main(String[] args) throws ClassNotFoundException, SQLException {
    // TODO Auto-generated method stub
    connect();
}

此外，maven 依赖项如下所示：

<dependencies>
    <dependency>
        <groupId>com.facebook.presto</groupId>
        <artifactId>presto-cassandra</artifactId>
        <version>0.72</version>
        <type>zip</type>
    </dependency>
    <dependency>
        <groupId>com.facebook.presto</groupId>
        <artifactId>presto-jdbc</artifactId>
        <version>0.72</version>
    </dependency>
</dependencies>`

但是当我运行这段代码时，我得到：

***juil. 02, 2014 11:32:57 AM com.facebook.presto.jdbc.internal.jetty.util.log.JavaUtilLog info
INFOS: Logging initialized @122ms
Exception in thread "main" java.sql.SQLException: Error executing query
    at com.facebook.presto.jdbc.PrestoStatement.executeQuery(PrestoStatement.java:54)
    at tester_cass.connect(tester_cass.java:19)
    at tester_cass.main(tester_cass.java:26)
Caused by: java.lang.IllegalStateException: Response does not contain a JSON value
    at com.facebook.presto.jdbc.internal.airlift.http.client.FullJsonResponseHandler$JsonResponse.getValue(FullJsonResponseHandler.java:148)
    at com.facebook.presto.jdbc.internal.client.StatementClient.<init>(StatementClient.java:82)
    at com.facebook.presto.jdbc.QueryExecutor.startQuery(QueryExecutor.java:60)
    at com.facebook.presto.jdbc.PrestoConnection.startQuery(PrestoConnection.java:541)
    at com.facebook.presto.jdbc.PrestoStatement.executeQuery(PrestoStatement.java:49)
    ... 2***

问题是什么？

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1 回答 1

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隔离问题：

于 2014-07-07T14:21:32.507 回答