HBase重要参数，其他的参数查看文件

设置hadoop的系统参数时可以使用-D ,这个要放在程序参数的前面

使用HBASE作为输入

 public static class MapClass extends TableMapper...

可以使用TableInputFormate的参数

hbase.mapreduce.inputtable hbase.mapreduce.scan / 输入字符串转换为Scan */ hbase.mapreduce.scan.row.start / Scan start row */ hbase.mapreduce.scan.row.stop / Scan stop row */ hbase.mapreduce.scan.column.family / Column Family to Scan */ hbase.mapreduce.scan.columns / Space delimited list of columns to scan. */ hbase.mapreduce.scan.timestamp / The timestamp used to filter columns with a specific timestamp. */ hbase.mapreduce.scan.timerange.start hbase.mapreduce.scan.timerange.end hbase.mapreduce.scan.maxversions hbase.mapreduce.scan.cacheblocks / Set to false to disable server-side caching of blocks for this scan. */ hbase.mapreduce.scan.cachedrows / The number of rows for caching that will be passed to scanners. */

注意要点：

使用HBASE的时候建议关闭 冗余工作  Speculative Execution

mapred.map.tasks.speculative.execution=false mapred.reduce.tasks.speculative.execution= false