以下是hadoop的wordcount示例中的代码示例：

class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable> {
    private Text outputKey;
    private IntWritable outputVal;

    @Override
    public void setup(Context context) {
        outputKey = new Text();
        outputVal = new IntWritable(1);
    }

    @Override
    public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
        StringTokenizer stk = new StringTokenizer(value.toString());
        while(stk.hasMoreTokens()) {
          outputKey.set(stk.nextToken());
          context.write(outputKey, outputVal);
        }
    }
}

只有一个 outputKey 示例。在 while 回路， outputKey 设置不同的单词，并将其作为 context . 是 outputKey 示例在整个系统中共享 <key, value> 对？
为什么不用 context.write(new Text(stk.nextToken()), new IntWritable(1)) ?