hadoop - 为什么 mapper 会抛出 ArrayIndexoutofboundexception？

Question

我正在尝试逐行读取 CSV 文件，并发送包含“India”作为子字符串的那些行的键值对。为此，我开发了以下代码。

映射器代码

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;


public class MapperCode extends Mapper<LongWritable,Text,Text,IntWritable> {
    public void map(LongWritable key,Text value,Context context) throws IOException,InterruptedException
    {
        String Line=value.toString();
        String out="";
        String search_line=Line;
        String splitter[]=Line.split(" ");
        String searchStr="india";
        for(String words:splitter)
        {
            if(searchStr.equals(words))
            {
                 out=out+"\n"+search_line;
                 System.out.println(out);
            }
        }
        String keyvalpair[]=out.split(",");
        context.write(new Text(keyvalpair[2].trim()), new IntWritable(Integer.parseInt(keyvalpair[9].trim())));
    }
}

数据集

Clarissa Chun,30,United States,2012,08-12-2012,Wrestling,0,0,1,1
Yogeshwar Dutt,29,India,2012,08-12-2012,Wrestling,0,0,1,1
Jaime Espinal,27,Puerto Rico,2012,08-12-2012,Wrestling,0,1,0,1
Johan Eurén,27,Sweden,2012,08-12-2012,Wrestling,0,0,1,1
Karam Gaber,32,Egypt,2012,08-12-2012,Wrestling,0,1,0,1

异常

17/03/17 21:11:08 INFO mapred.JobClient: Task Id :        attempt_201703140915_0030_m_000000_1, Status : FAILED
java.lang.ArrayIndexOutOfBoundsException: 2
        at MapperCode.map(MapperCode.java:26)
        at MapperCode.map(MapperCode.java:1)
        at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
        at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:647)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:323)
        at org.apache.hadoop.mapred.Child$4.run(Child.java:270)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:396)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1127)
        at org.apache.hadoop.mapred.Child.main(Child.java:264)

请帮帮我。提前致谢!

Answer 1

问题就出在这里。

  String splitter[]=Line.split(" ");   

您正在尝试使用“空格”进行拆分。在这种特殊情况下，您可以使用“,”

String splitter[]=Line.split(",");

这应该可以正常工作。