可以直接使用org.apache.hadoop.yarn.client.cli.LogsCLI（yarn logs -applicationId）中的main方法逻辑，如

public static void main(String[] args)

throws Exception

{

Configuration conf = new YarnConfiguration();

conf.addResource(new Path("/etc/hadoop/conf.cloudera.yarn/core-site.xml"));

conf.addResource(new Path("/etc/hadoop/conf.cloudera.yarn/yarn-site.xml"));

conf.addResource(new Path("/etc/hadoop/conf.cloudera.yarn/hdfs-site.xml"));

LogsCLI logDumper = new LogsCLI();

logDumper.setConf(conf);

int exitCode = logDumper.run(args);

System.exit(exitCode);

}

也可以仿照他的逻辑自己实现如下：

Configuration conf = new YarnConfiguration();

conf.addResource(new Path("/etc/hadoop/conf.cloudera.yarn/core-site.xml"));

conf.addResource(new Path("/etc/hadoop/conf.cloudera.yarn/yarn-site.xml"));

conf.addResource(new Path("/etc/hadoop/conf.cloudera.yarn/hdfs-site.xml"));

String appIdStr="application_1529377575914_8380";

PrintStream out=new PrintStream(appIdStr);

ApplicationId appId = null;

appId = ConverterUtils.toApplicationId(appIdStr);

Path remoteRootLogDir = new Path(conf.get("yarn.nodemanager.remote-app-log-dir", "/tmp/logs"));

String user = UserGroupInformation.getCurrentUser().getShortUserName();;

String logDirSuffix = LogAggregationUtils.getRemoteNodeLogDirSuffix(conf);

Path remoteAppLogDir = LogAggregationUtils.getRemoteAppLogDir(remoteRootLogDir, appId, user, logDirSuffix);

RemoteIterator<FileStatus> nodeFiles;

try

{

Path qualifiedLogDir = FileContext.getFileContext(conf).makeQualified(remoteAppLogDir);

nodeFiles = FileContext.getFileContext(qualifiedLogDir.toUri(), conf).listStatus(remoteAppLogDir);

}

catch (FileNotFoundException fnf)

{

logDirNotExist(remoteAppLogDir.toString());

return -1;

}

boolean foundAnyLogs = false;

while (nodeFiles.hasNext())

{

FileStatus thisNodeFile = (FileStatus)nodeFiles.next();

if (!thisNodeFile.getPath().getName().endsWith(".tmp"))

{

AggregatedLogFormat.LogReader reader = new AggregatedLogFormat.LogReader(conf, thisNodeFile.getPath());

try

{

//System.out.println(thisNodeFile.getPath().getName());

AggregatedLogFormat.LogKey key = new AggregatedLogFormat.LogKey();

DataInputStream valueStream = reader.next(key);

for (;;)

{

if (valueStream != null)

{

String containerString = "\n\nContainer: " + key + " on " + thisNodeFile.getPath().getName();

out.println(containerString);

out.println(StringUtils.repeat("=", containerString.length()));

try

{

for (;;)

{

AggregatedLogFormat.LogReader.readAContainerLogsForALogType(valueStream, out, thisNodeFile.getModificationTime());

foundAnyLogs = true;

}

}

catch (EOFException eof)

{

key = new AggregatedLogFormat.LogKey();

valueStream = reader.next(key);

}

}else{

break;

}

}

}

finally

{

reader.close();

}

}

}

if (!foundAnyLogs)

{

emptyLogDir(remoteAppLogDir.toString());

return -1;

}

return 0;

}