类 org.apache.hadoop.mapreduce.Reducer.Context
的使用

使用Reducer.Context的程序包

程序包	说明
org.apache.hadoop.examples	Hadoop example code.
org.apache.hadoop.mapred	A software framework for easily writing applications which process vast amounts of data (multi-terabyte data-sets) parallelly on large clusters (thousands of nodes) built of commodity hardware in a reliable, fault-tolerant manner.
org.apache.hadoop.mapreduce
org.apache.hadoop.mapreduce.lib.fieldsel
org.apache.hadoop.mapreduce.lib.reduce

org.apache.hadoop.examples中Reducer.Context的使用

参数类型为Reducer.Context的org.apache.hadoop.examples中的方法

限定符和类型	方法和说明
void	SecondarySort.Reduce.reduce(SecondarySort.IntPair key, Iterable<IntWritable> values, Reducer.Context context)
void	WordCount.IntSumReducer.reduce(Text key, Iterable<IntWritable> values, Reducer.Context context)

org.apache.hadoop.mapred中Reducer.Context的使用

返回Reducer.Context的org.apache.hadoop.mapred中的方法

限定符和类型	方法和说明
protected static <INKEY,INVALUE,OUTKEY,OUTVALUE> Reducer.Context	Task.createReduceContext(Reducer<INKEY,INVALUE,OUTKEY,OUTVALUE> reducer, Configuration job, TaskAttemptID taskId, RawKeyValueIterator rIter, Counter inputKeyCounter, Counter inputValueCounter, RecordWriter<OUTKEY,OUTVALUE> output, OutputCommitter committer, StatusReporter reporter, RawComparator<INKEY> comparator, Class<INKEY> keyClass, Class<INVALUE> valueClass)

org.apache.hadoop.mapreduce中Reducer.Context的使用

参数类型为Reducer.Context的org.apache.hadoop.mapreduce中的方法

限定符和类型	方法和说明
protected void	Reducer.cleanup(Reducer.Context context) Called once at the end of the task.
protected void	Reducer.reduce(KEYIN key, Iterable<VALUEIN> values, Reducer.Context context) This method is called once for each key.
void	Reducer.run(Reducer.Context context) Advanced application writers can use the Reducer.run(org.apache.hadoop.mapreduce.Reducer.Context) method to control how the reduce task works.
protected void	Reducer.setup(Reducer.Context context) Called once at the start of the task.

org.apache.hadoop.mapreduce.lib.fieldsel中Reducer.Context的使用

参数类型为Reducer.Context的org.apache.hadoop.mapreduce.lib.fieldsel中的方法

限定符和类型	方法和说明
void	FieldSelectionReducer.reduce(Text key, Iterable<Text> values, Reducer.Context context)
void	FieldSelectionReducer.setup(Reducer.Context context)

org.apache.hadoop.mapreduce.lib.reduce中Reducer.Context的使用

参数类型为Reducer.Context的org.apache.hadoop.mapreduce.lib.reduce中的方法

限定符和类型	方法和说明
void	IntSumReducer.reduce(Key key, Iterable<IntWritable> values, Reducer.Context context)
void	LongSumReducer.reduce(KEY key, Iterable<LongWritable> values, Reducer.Context context)