dealWriteMode()
JobContainer
init()
调用SingleTableSplitUtil按照主键划分并生成分页查询的SQL
initJobWriter()
preHandle()
initJobReader()
start()
CommonRdbmsWriter.Job
MysqlReader
split()
初始化Writer
doPretreatment()
DbUtil
entry()
初始化Reader
CommonRdbmsReader.Job
getTableColumnsByConn()
MysqlWriter
生成insert语句
schedule()
Engine
writerOriginalConfPretreatmentUtil
dealColumnConf()
readerOriginalConfPretreatmentUtil
simplifyConf()
返回要插入的列名
