RecordWriter接口解析
RecordWriter是将Map/Reduce结果(Key-Value)输出到文件系统中。
/** * <code>RecordWriter</code> writes the output <key, value> pairs * to an output file. * <p><code>RecordWriter</code> implementations write the job outputs to the * {@link FileSystem}. * * @see OutputFormat */ @InterfaceAudience.Public @InterfaceStability.Stable public abstract class RecordWriter<K, V> { /** * Writes a key/value pair. * 将Map/Reduce结果的key/value写到文件系统中去。 * @param key the key to write. * @param value the value to write. * @throws IOException */ public abstract void write(K key, V value) throws IOException, InterruptedException; /** * Close this <code>RecordWriter</code> to future operations. * 关闭输出操作 * @param context the context of the task * @throws IOException */ public abstract void close(TaskAttemptContext context) throws IOException, InterruptedException; }