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我想列出HDFS内存在的目录的内容。我尝试了下面的代码:FileSystem listStatus引发NullPointerException
public static void main(String[] args) throws IOException {
String uri = args[1];
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(URI.create(uri),conf);
for(int i=0;i<args.length;i++){
System.out.println("Args: " + args[i]);
}
Path[] paths = new Path[args.length];
for(int i=1; i<args.length;i++){
paths[i] = new Path(args[i]);
System.out.println(paths[i]);
}
FileStatus[] status = fs.listStatus(paths);
Path[] listedPaths = FileUtil.stat2Paths(status);
for(Path p : listedPaths){
System.out.println(p);
}
}
但我得到一个异常:
Exception in thread "main" java.lang.NullPointerException
at org.apache.hadoop.fs.FileSystem.fixRelativePart(FileSystem.java:2198)
at org.apache.hadoop.hdfs.DistributedFileSystem.listStatus(DistributedFileSystem.java:697)
at org.apache.hadoop.fs.FileSystem.listStatus(FileSystem.java:1482)
at org.apache.hadoop.fs.FileSystem.listStatus(FileSystem.java:1559)
at org.apache.hadoop.fs.FileSystem.listStatus(FileSystem.java:1539)
at com.demo.ListStatusDemo.main(ListStatusDemo.java:29)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.RunJar.main(RunJar.java:212)
请让我知道这一点。
我改变了指数'路径[i-1] =新路径(args [i]);'但仍然得到相同的异常。请指教。 – user182944
@ user182944如果你做了'paths [i-1]',那么'paths [paths.length-1]'的路径将为空,因此是例外。 –
是的,只要{Path [] paths = new Path [args.length-1];} – yurgis