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今天在论坛上看见一个函数cleanup。查了下API。发现Mapper和Reducer都实现了这个函数。
描述:cleanup protected void cleanup(Mapper.Context context) throws IOException, InterruptedExceptionCalled once at the end of the task. Throws: IOException InterruptedException
论坛上的那个人来这个函数来统计总的词频数:
public void cleanup(Context context) throws IOException, InterruptedException { context.write(new Text("sum"), new IntWritable(sum)); }
这个用法不错,记上一笔。
在查看cleanuo函数的同时,还有一个类似的函数:
setup protected void setup(Mapper.Context context) throws IOException, InterruptedExceptionCalled once at the beginning of the task. Throws: IOException InterruptedException