java.sql.SQLException: Streaming result set com.mysql.jdbc.RowDataDynamic@27ce24aa is still active. No statements may be issued when any streaming result sets are open and in use on a given connection

在Sqoop往mysql导出数据的时候报了这个错误，一开始还以为是jar包没有打进去或者打错位置了，未解便上网查询。

Error reading from database: java.sql.SQLException: Streaming result set com.mysql.jdbc.RowDataDynamic@27ce24aa is still active. No statements may be issued when any streaming result sets are open and in use on a given connection. Ensure that you have called .close() on any active streaming result sets before attempting more queries.
java.sql.SQLException: Streaming result set com.mysql.jdbc.RowDataDynamic@27ce24aa is still active. No statements may be issued when any streaming result sets are open and in use on a given connection. Ensure that you have called .close() on any active streaming result sets before attempting more queries.

1.通过百度寻找此问题的解决方式，找到了如下答案：

由于mysql-connector-java的bug造成的，出错时我用的是mysql-connector-java-5.1.12-bin.jar，更新成mysql-connector-java-5.1.32-bin.jar就可以了。

但是我通过wget http://dev.mysql.com/get/Downloads/Connector-J/mysql-connector-java-5.1.32.tar.gz，下载了tar.gz包 解压之后得到mysql-connector-java-5.1.32-bin.jar

注意mysql-connector-java-5.1.32-bin.jar，看见没有是-bin.jar，maven项目的pom.xml中添加mysql依赖，会产出mysql-connector-java-5.1.32.jar 没有-bin，注意这是两个不同的包。

千万不要直接从项目中拷过来。。。最后替换掉sqoop目录原有jar包，我的目录是/opt/software/sqoop/lib/

但是！！！并没有解决这个问题。。。

2. 科学上网

老大看我焦头烂额却没有丝毫进展，告知我要科学上网，这种问题要到墙外查阅资料。我也知道，但是最近vpn好笑来月经了似的翻不出去了。。。

大哥最后出马，在StackOverFlow上找到了答案：

Try including the option --driver com.mysql.jdbc.Driver in the import command.

Worked for me...Thanks Man

sqoop export \
--connect $STAT_JDBC_CONNECT \
--username $JDBC_USERNAME \
--password $JDBC_PASSWORD \
--table $TABLE \
--update-mode allowinsert \
--driver com.mysql.jdbc.Driver \
--export-dir $SQOOP_HDFS_RESULT_DAY \
--columns stat_ds,command,answer,counts

3.解决这个问题，便深知科学上网的重要性，便开始研究vpn为何失效翻不过去长城？

我用的工具ShadowSocks，找了半天没有类似的经验，就把电脑关机。重启之后在没有改任何配置的前提下就好了！

4.SparkSql中使用round内置函数完成四舍五入保留两位小数

  /**
    * 统计音箱型号分布情况
    *
    * @param dataFrame
    * @return
    */
  def echoModelDistributeStat(dataFrame: DataFrame, preDay: String): List[String] = {
    var numdf = dataFrame.groupBy("model").agg(count("model").as("model_count"))
    // 统计出总共的设备数
    var sumdf = numdf.groupBy().agg(sum("model_count"))
    // 计算设备型号的总数量
    var modelSum = sumdf.collect()(0)(0)
    // 计算出需要的的DF
    var modelInfo = numdf.select(numdf("model"), numdf("model_count"), (numdf("model_count") / modelSum * 100).as("model_percent"))
    modelInfo.registerTempTable("m")
    // 将日期转换为时间戳
    val timeStamp = TimeUtils.getTimeStamp(preDay + " " + Constant.TIME_ZERO)
    val timeDf = modelInfo.sqlContext.sql("select " + timeStamp + " as stat_ds,m.model,m.model_count,round(m.model_percent,2) as model_percent from m")
    // 将DF转成List[Row]的形式
    val list = timeDf.collect().toList
    // 将List[Row]转为List[String]
    val listStr = listRowConvertListStr(list)
    return listStr
  }