Myeclipase下运行hdfs api测试程序，报wrong fs

伪分布式下 hadoop 0.20.2：

 

代码如下，简单的api访问：

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;


import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;


public class FileRW {
    public static void main(String[] args) throws Exception{
        String str = new String();
        String uri = args[0];
        Path srcPath = new Path(uri);
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(conf);
        //FileSystem fs = srcPath.getFileSystem(conf);
        
        if (fs.exists(srcPath))
         {
             InputStream input = fs.open(srcPath);
             InputStreamReader isr =  new InputStreamReader(input,"GBK");
        //     FileStatus state = fs.getFileStatus(srcPath);
             BufferedReader br = new BufferedReader(isr);
             while((str = br.readLine()) != null)
             {
                 System.out.println(str);
                 str = null;
             }
             input.close();
         }
    }
}

run as java Application。然后报错：

Exception in thread "main" java.lang.IllegalArgumentException: Wrong FS: hdfs://analyze:9000/user/root/MahoutInput/test.txt, expected: file:///
    at org.apache.hadoop.fs.FileSystem.checkPath(FileSystem.java:310)
    at org.apache.hadoop.fs.RawLocalFileSystem.pathToFile(RawLocalFileSystem.java:47)
    at org.apache.hadoop.fs.RawLocalFileSystem.getFileStatus(RawLocalFileSystem.java:357)
    at org.apache.hadoop.fs.FilterFileSystem.getFileStatus(FilterFileSystem.java:245)
    at org.apache.hadoop.fs.FileSystem.exists(FileSystem.java:648)
    at FileRW.main(FileRW.java:20)

网上查找到解决方法：

将原代码中的(红色标注部分)：

FileSystem fs = FileSystem.get(conf);
改成

FileSystem fs = srcPath.getFileSystem(conf);
后，运行成功。

原因不清楚，可能是伪分布式原因？