buketname:zhaoweilin Part1:first get the number of the White Black and Draw,then throught reducer to get the percentage Part2:first get the name of the player + white/black/draw and the number of winning games,then get the number of total games,and at last calculate the percentage Part3:I start two MR jobs, the first output the number of each PlayCount, the use context.getCounter("org.apache.hadoop.mapred.Task$Counter", "MAP_OUTPUT_RECORDS").getValue() to get the number of matches,and set it as a global variable in conf the second job is to calculate the percentage of each PlayCount and sort it by percentage through public static class SortKeyComparator extends WritableComparator, overwrite the