我编写了一个MapReduce作业,用于在使用旧API存储在HDFS中的输入文件中查找搜索字符串(通过命令行参数传递)的发生。MapReduce旧API - 将命令行参数传递到地图
下面是我的Driver类 -
public class StringSearchDriver
{
public static void main(String[] args) throws IOException
{
JobConf jc = new JobConf(StringSearchDriver.class);
jc.set("SearchWord", args[2]);
jc.setJobName("String Search");
FileInputFormat.addInputPath(jc, new Path(args[0]));
FileOutputFormat.setOutputPath(jc, new Path(args[1]));
jc.setMapperClass(StringSearchMap.class);
jc.setReducerClass(StringSearchReduce.class);
jc.setOutputKeyClass(Text.class);
jc.setOutputValueClass(IntWritable.class);
JobClient.runJob(jc);
}
}
下面是我的映射类 -
public class StringSearchMap extends MapReduceBase implements
Mapper<LongWritable, Text, Text, IntWritable>
{
String searchWord;
public void configure(JobConf jc)
{
searchWord = jc.get("SearchWord");
}
@Override
public void map(LongWritable key, Text value,
OutputCollector<Text, IntWritable> out, Reporter reporter)
throws IOException
{
String[] input = value.toString().split("");
for(String word:input)
{
if (word.equalsIgnoreCase(searchWord))
out.collect(new Text(word), new IntWritable(1));
}
}
}
在运行作业(通过命令行字符串 “HI”),我得到下面的错误 -
14/09/21 22:35:41 INFO mapred.JobClient: Task Id : attempt_201409212134_0005_m_000001_2, Status : FAILED
java.lang.ClassCastException: interface javax.xml.soap.Text
at java.lang.Class.asSubclass(Class.java:3129)
at org.apache.hadoop.mapred.JobConf.getOutputKeyComparator(JobConf.java:795)
at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:964)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:422)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:366)
at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:416)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190)
at org.apache.hadoop.mapred.Child.main(Child.java:249)
请建议。
'ClassCastException:interface javax.xml.soap.Text'看起来像在源代码中自动导入了错误的Text类? – jkovacs 2014-09-21 21:49:32