mongodb - 使用 ycsb 工具进行 mongodb 时出错

Question

我正在尝试使用 ycsb 工具测试 mongodb。我安装了 java 和 maven，我已经从https://github.com/brianfrankcooper/YCSB下载了 ycsb-master 我运行 mvn clean package 命令以便 mongodb 绑定成功。加载工作量我执行了以下命令

C:\YCSB-master\bin>c:\Python27\python.exe ycsb load mongodb -s -P 工作负载\workloada -p recordcount=1000 -threads 6 -p mongodb.url="mongodb://localhost:27017" -p mongodb.database=test -p writeConcern=normal -p mongodb.auth="true"

但我收到了类似的错误

[WARN]  Running against a source checkout. In order to get our runtime dependencies we'll have to invoke Maven. Depending on the state of your system, this may take ~30-45 seconds    
[DEBUG]  Running 'mvn -pl com.yahoo.ycsb:mongodb-binding -am package -DskipTests dependency:build-classpath -DincludeScope=compile -Dmdep.outputFilterFile=true'   
Traceback (most recent call last):
  File "ycsb", line 259, in <module>
    sys.exit(main())
  File "ycsb", line 232, in main
    maven_says = get_classpath_from_maven(project)
  File "ycsb", line 178, in get_classpath_from_maven+ err.output)
TypeError: cannot concatenate 'str' and 'NoneType' objects

请帮我