本地调试
直接Debug As 执行Demo会报错：
ERROR: Cannot load this JVM TI agent twice, check your Java command line for duplicate jdwp options.
Error occurred during initialization of VM
agent library failed to init: jdwp
解决办法：
编辑Demo.launch
找到<stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value=" -Xdebug -Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=n -Dplay.debug=yes ...>
将-Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=n去掉！
附加Play源码，即可调试Play本身。