hadoop上下文信息获取方法
import java.io.IOException;import java.net.URI;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.JobID;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.TaskAttemptID;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
public>
public static void main(String[] args) throws IOException,>
Configuration conf = new Configuration();
// String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
if(args.length!=2){
System.err.println("Usage databaseV1 <inputpath> <outputpath>");
}
Job job = Job.getInstance(conf, GetIDMapReduce.class.getSimpleName() + "1");
job.setJarByClass(GetIDMapReduce.class);
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(Text.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(NullWritable.class);
job.setMapperClass(MyMapper1.class);
job.setNumReduceTasks(0);
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
FileInputFormat.addInputPath(job, new Path(args));
FileOutputFormat.setOutputPath(job, new Path(args));
job.waitForCompletion(true);
}
public static>
@Override
protected void map(LongWritable key, Text value, Mapper<LongWritable, Text, Text, NullWritable>.Context context)
throws IOException, InterruptedException {
FileSplit fileSplit=(FileSplit) context.getInputSplit();
String pathname=fileSplit.getPath().getName();
JobID jobid=context.getJobID(); //获取jobid
LongWritable keyout=context.getCurrentKey(); //获取key偏移量
Text valueout=context.getCurrentValue();//获取一行的值
String jobname=context.getJobName(); //获得job名字
TaskAttemptID taskid=context.getTaskAttemptID(); //获得taskid
float progress=context.getProgress(); //获取任务执行进度
String jar = context.getJar();//作业运行之前，往集群拷贝的作业资源jar
//String status = context.getStatus();
String user = context.getUser(); //获取当前用户
//String[] fileTimestamps = context.getFileTimestamps();
int numReduceTasks = context.getNumReduceTasks(); //获得reduce的数量
//Path[] fileClassPaths = context.getFileClassPaths();
Configuration configuration = context.getConfiguration(); //获得作业配置文件
//RawComparator<?> groupingComparator = context.getGroupingComparator();
boolean jobSetupCleanupNeeded = context.getJobSetupCleanupNeeded(); //Get whether job-setup and job-cleanup is needed for the job
int maxMapAttempts = context.getMaxMapAttempts(); //the max number of attempts per map task
int maxReduceAttempts = context.getMaxReduceAttempts(); //he max number of attempts per reduce task.
//@SuppressWarnings("deprecation")
//Path[] localCacheFiles = context.getLocalCacheFiles();
//OutputCommitter outputCommitter = context.getOutputCommitter();
Path workingDirectory = context.getWorkingDirectory(); //工作目录
boolean nextKeyValue = context.nextKeyValue();//下一个键值对
//URI[] cacheFiles = context.getCacheFiles();
URI[] cacheArchives = context.getCacheArchives(); //Get cache archives set in the Configuration
Path[] archiveClassPaths = context.getArchiveClassPaths();//Get the archive entries in>
boolean profileEnabled = context.getProfileEnabled();//Get whether the task profiling is enabled.
//String profileParams = context.getProfileParams();
@SuppressWarnings("deprecation")
boolean symlink = context.getSymlink();// Originally intended to check if symlinks should be used, but currently symlinks cannot be disabled
//RawComparator<?> sortComparator = context.getSortComparator();
//int hashCode = context.hashCode();
context.write(new Text("===================================================================================="), NullWritable.get());
context.write(new Text("pathname--"+pathname), NullWritable.get());
context.write(new Text("jobid--"+jobid.toString()), NullWritable.get());
context.write(new Text("keyout--"+keyout.toString()), NullWritable.get());
context.write(new Text("keyout--"+valueout), NullWritable.get());
context.write(new Text("jobname--"+jobname), NullWritable.get());
context.write(new Text("taskid--"+taskid.toString()), NullWritable.get());
context.write(new Text("progress--"+progress), NullWritable.get());
context.write(new Text("jar--"+jar.toString()), NullWritable.get());
//context.write(new Text("status--"+status), NullWritable.get());
context.write(new Text("user--"+user), NullWritable.get());
//context.write(new Text("fileTimestamps--"+fileTimestamps), NullWritable.get());
context.write(new Text("numReduceTasks--"+numReduceTasks), NullWritable.get());
//context.write(new Text("fileClassPaths--"+fileClassPaths), NullWritable.get());
context.write(new Text("configuration--"+configuration), NullWritable.get());
//context.write(new Text("groupingComparator--"+groupingComparator), NullWritable.get());
context.write(new Text("jobSetupCleanupNeeded--"+jobSetupCleanupNeeded), NullWritable.get());
context.write(new Text("maxMapAttempts--"+maxMapAttempts), NullWritable.get());
context.write(new Text("maxReduceAttempts--"+maxReduceAttempts), NullWritable.get());
//context.write(new Text("localCacheFiles--"+localCacheFiles), NullWritable.get());
//context.write(new Text("outputCommitter--"+outputCommitter), NullWritable.get());
context.write(new Text("workingDirectory--"+workingDirectory), NullWritable.get());
context.write(new Text("nextKeyValue--"+nextKeyValue), NullWritable.get());
//context.write(new Text("cacheFiles--"+cacheFiles), NullWritable.get());
context.write(new Text("cacheArchives--"+cacheArchives), NullWritable.get());
context.write(new Text("archiveClassPaths--"+archiveClassPaths), NullWritable.get());
context.write(new Text("profileEnabled--"+profileEnabled), NullWritable.get());
//context.write(new Text("profileParams--"+profileParams), NullWritable.get());
context.write(new Text("symlink--"+symlink), NullWritable.get());
//context.write(new Text("sortComparator--"+sortComparator), NullWritable.get());
//context.write(new Text("hashCode--"+hashCode), NullWritable.get());
}
}
}
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