org.apache.hadoop.security.AccessControlException): Permission denied: user=Yongfeng, access=WRITE, inode="/user/hadoop/test.txt

solution.md

有几种解决办法

1. 去掉hdfs的permissions:

<property>
  <name>dfs.permissions</name>
  <value>false</value>
</property>

这个一定有效...

2. 设置系统HADOOP_USER_NAME

System.setProperty("HADOOP_USER_NAME", "hduser")

3. 使用UserGroupInformation

UserGroupInformation ugi = UserGroupInformation.createRemoteUser("hduser"); 
ugi.doAs(new PrivilegedExceptionAction<Void>() {
    public Void run() throws Exception {
        Configuration configuration = new Configuration(); 
        // 写一些东西
        FileSystem fs = FileSystem.get(new URI("hdfs://192.168.1.108:9000"), configuration);
        Path outFile = new Path("/user/hadoop/test.txt");
        FSDataOutputStream out = fs.create(outFile);
        BufferedWriter br=new BufferedWriter(new OutputStreamWriter(out));
        br.write("This is test string");
        br.close();
    }
});