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