覆蓋RecordReader一次而不是行

Question

重寫RecordReader類的方法「下一步」和TextInputFormat類的「getRecordReader」以便發送整個段落到映射器而不是逐行。 （我用舊的API和認定中對我的款追加至一個空行來在我的文本文件的時間。）
下面是我的代碼：

public class NLinesInputFormat extends TextInputFormat 
{ 
    @Override 
    public RecordReader<LongWritable, Text> getRecordReader(InputSplit split, JobConf conf, Reporter reporter)throws IOException  { 
     reporter.setStatus(split.toString()); 
     return new ParagraphRecordReader(conf, (FileSplit)split); 
    } 
} 



public class ParagraphRecordReader implements RecordReader<LongWritable, Text> 
{ 
     private LineRecordReader lineRecord; 
     private LongWritable lineKey; 
     private Text lineValue; 
     public ParagraphRecordReader(JobConf conf, FileSplit split) throws IOException { 
      lineRecord = new LineRecordReader(conf, split); 
      lineKey = lineRecord.createKey(); 
      lineValue = lineRecord.createValue(); 
     } 

     @Override 
     public void close() throws IOException { 
      lineRecord.close(); 
     } 

     @Override 
     public LongWritable createKey() { 
      return new LongWritable(); 

     } 

     @Override 
     public Text createValue() { 
      return new Text(""); 

     } 

     @Override 
     public float getProgress() throws IOException { 
      return lineRecord.getPos(); 

     } 

     @Override 
     public synchronized boolean next(LongWritable key, Text value) throws IOException { 
      boolean appended, gotsomething; 
      boolean retval; 
      byte space[] = {' '}; 
      value.clear(); 
      gotsomething = false; 
      do { 
       appended = false; 
       retval = lineRecord.next(lineKey, lineValue); 
       if (retval) { 
        if (lineValue.toString().length() > 0) { 
         byte[] rawline = lineValue.getBytes(); 
         int rawlinelen = lineValue.getLength(); 
         value.append(rawline, 0, rawlinelen); 
         value.append(space, 0, 1); 
         appended = true; 
        } 
        gotsomething = true; 
       } 
      } while (appended); 

      //System.out.println("ParagraphRecordReader::next() returns "+gotsomething+" after setting value to: ["+value.toString()+"]"); 
      return gotsomething; 
     } 

     @Override 
     public long getPos() throws IOException { 
      return lineRecord.getPos(); 
     } 
    } 

問題：
1.我沒有找到任何具體的指導如何做到這一點，所以可能是我做錯了，請評論任何建議？
2.我能夠正確編譯，但是當我運行我的作業時，我的映射器不斷運行，我無法弄清楚問題出在哪裏？

Answer 1

你的代碼對我來說工作得很好。 我做的唯一改變是將這些類作爲內部類並使它們變爲靜態。

輸入文件如下：

This is awesome. 
WTF is this. 

This is just a test. 

映射器的代碼看起來像：

@Override 
public void map(LongWritable key, Text value, OutputCollector<Text, Text> output, Reporter reporter) 
    throws IOException { 

    System.out.println(key+" : "+value); 
} 

而且輸出是：

0 : This is awesome. WTF is this. 
0 : This is just a test. 

我相信你會避風港忘記設置輸入格式，但爲了以防萬一，請將其設置爲以下內容ws：

conf.setInputFormat(NLinesInputFormat.class);