hadoop,java.lang.RuntimeException:java.lang.ClassNotFoundException错误
我正在阅读这本书(hadoop权威指南) 在尝试使用localhost执行书中的一个示例时,我遇到了一个错误hadoop,java.lang.RuntimeException:java.lang.ClassNotFoundException错误,java,hadoop,mapreduce,Java,Hadoop,Mapreduce,我正在阅读这本书(hadoop权威指南) 在尝试使用localhost执行书中的一个示例时,我遇到了一个错误 14/06/13 22:24:57 WARN mapred.JobClient: No job jar file set. User classes may not be found. See JobConf(Class) or JobConf#setJar(String). ****hdfs://localhost/usr/kim/input/ncdc 14/06/13 22:24:
14/06/13 22:24:57 WARN mapred.JobClient: No job jar file set. User classes may not be found. See JobConf(Class) or JobConf#setJar(String).
****hdfs://localhost/usr/kim/input/ncdc
14/06/13 22:24:57 INFO input.FileInputFormat: Total input paths to process : 3
14/06/13 22:24:57 WARN snappy.LoadSnappy: Snappy native library is available
14/06/13 22:24:57 INFO util.NativeCodeLoader: Loaded the native-hadoop library
14/06/13 22:24:57 INFO snappy.LoadSnappy: Snappy native library loaded
14/06/13 22:24:57 INFO mapred.JobClient: Running job: job_201406132100_0011
14/06/13 22:24:58 INFO mapred.JobClient: map 0% reduce 0%
14/06/13 22:25:11 INFO mapred.JobClient: Task Id : attempt_201406132100_0011_m_000000_0, Status : FAILED
java.lang.RuntimeException: java.lang.ClassNotFoundException: mapred.MaxTemperatureMapper_v1
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:867)
at org.apache.hadoop.mapreduce.JobContext.getMapperClass(JobContext.java:199)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:719)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
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:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1093)
at org.apache.hadoop.mapred.Child.main(Child.java:249)
Caused by: java.lang.ClassNotFoundException: mapred.MaxTemperatureMapper_v1
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:270)
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:820)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:865)
... 8 more
我使用命令行执行作业,hadoop jar MaxTemperatureDriver.jar mapred.MaxTemperatureDriver-conf/hadoop\u conf/hadoop-localhost.xml/input/ncdc/max temp
jar文件中有2个文件夹META-INF
,mapred
,mapred文件夹中有5个类(这些类在mapred
包中)
<?xml version="1.0"?>
<configuration>
<property>
<name>fs.default.name</name>
<value>hdfs://localhost/</value>
</property>
<property>
<name>mapred.job.tracker</name>
<value>localhost:8021</value>
</property>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
</configuration>
fs.default.name
hdfs://localhost/
mapred.job.tracker
本地主机:8021
dfs.replication
1.
公共类MaxTemperatureDriver扩展配置的工具{
@凌驾
公共int运行(字符串[]args)引发异常{
如果(参数长度!=2){
System.err.printf(“用法:%s[通用选项]\n”,getClass().getSimpleName());
ToolRunner.printGenericCommandUsage(System.err);
返回-1;
}
作业作业=新作业(getConf(),“最高温度”);
setJarByClass(getClass());
addInputPath(作业,新路径(args[0]);
setOutputPath(作业,新路径(args[1]);
job.setReducerClass(MaxTemeratureReducer.class);
setMapperClass(MaxTemperatureMapper_v1.class);
job.setCombinerClass(MaxTemeratureReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
返回作业。waitForCompletion(true)?0:1;
}
}
公共类MaxTemperatureMapper\u v1扩展映射器{
枚举温度{
超过100
}
专用NcdcRecordParser parser=新的NcdcRecordParser();
@凌驾
公共void映射(LongWritable键、文本值、上下文上下文)引发IOException、InterruptedException{
parser.parse(value);//Text.toString()
if(parser.isValidTemperature()){
int airtimperature=parser.getairtimperature();
如果(空气温度>1000){
系统错误println(“输入温度超过100度:“+值”);
setStatus(“检测到可能损坏的记录:请参阅日志”);
获取计数器(温度超过100)。增量(1);
}
write(新文本(parser.getYear()),新IntWritable(parser.getAirTemperature());
}
}
}
根据类名设置jar有时会给出错误,并设置inputformat和output format,我希望这将对您有所帮助
job.setJarByClass(MaxTemperatureDriver.class);
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
job.setJarByClass(“主类”)
Main类意味着拥有Main()method我想你指的是job.setJarByClass(MaxTemperatureMapper.class);
public class MaxTemperatureMapper_v1 extends Mapper<LongWritable, Text, Text, IntWritable>{
enum Temperature{
OVER_100
}
private NcdcRecordParser parser = new NcdcRecordParser();
@Override
public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException{
parser.parse(value); //Text.toString()
if(parser.isValidTemperature()){
int airTemperature = parser.getAirTemperature();
if(airTemperature > 1000){
System.err.println("Temperature over 100 degrees for input: " + value);
context.setStatus("Detected possibly corrupt record: see logs.");
context.getCounter(Temperature.OVER_100).increment(1);
}
context.write(new Text(parser.getYear()), new IntWritable(parser.getAirTemperature()));
}
}
}
job.setJarByClass(MaxTemperatureDriver.class);
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);