if(cL.getResource("hadoop-site.xml")!=null) {//确保在类路径下不存在hadoop-site.xml(已过时) LOG.warn("DEPRECATED: hadoop-site.xml found in the classpath. " + "Usage of hadoop-site.xml is deprecated. Instead use core-site.xml, " + "mapred-site.xml and hdfs-site.xml to override ...
直接使用FileSystem以标准输出格式显示hadoop文件系统中的文件 public class FileSystemCat { public static void main(String[] args) throws IOException { String uri = args[0]; Configuration conf = new Configuration(); FileSystem fs = FileSystem.get(conf); InputStream in = null; try { in = fs....
fs = FileSystem.get(conf); //得到本地的文件系统 FileSystem fsLocal = FileSystem.getLocal(conf); //获得路径下的所有子文件路径 FileStatus[] globStatus = fs.listStatus(new Path("/user/hadoop/crawl/news/crawl_input/")); //读取路径下的所有SequenceFile 。 for (FileStatus fsFile : globStatus)...
这一部分的API中,Hadoop FileSystem和Java文件API比较大的差别,是获取文件或目录属性的方法。通过FileSystem.getFileStatus()方法,Hadoop抽象文件系统可以一次获得文件/目录的所有属性,这些属性被保存在类FileStatus中,如图所示。 通过FileStatus可以获得的信息包括:文件路径path、文件长度length、是否是目录isdir、副本数block...
FileSystem 对象是hdfs抽象目录树的一个实例,如果用户想要操作hdfs需要获取这个实例 获取实例的方式: 1)new 对象 2)反射的方式 3)通过工厂类 4)单例设计模式静态方法 5)克隆 Configuration对象是加载配置文件的对象 hadoop集群的时候 Configuration conf = new Configuration(); ...
Configurationconf=newConfiguration();//加载配置文件FileSystemfs=FileSystem.get(conf);//初始化文件系统 首先来看一下配置文件加载阶段。 这是Configuration类的静态代码块,默认加载core-default.xml和core-site.xml这两个配置文件。 static{//print deprecation warning if hadoop-site.xml is found in classpath...
HDFS uses a cluster architecture to help deliver high throughput. To reduce network traffic the Hadoop file system stores data in DataNodes where computations take place, rather than moving the data to another location for computation. Scalability ...
It's important to note that HDFS isn't POSIX-compliant and isn't a mountable file system on its own. HDFS is typically accessed via HDFS clients or by using application programming interface (API) calls from the Hadoop libraries. However, the development of a File system in User SpacE (...
作为现代分布式软件系统入门经典论文,The Google File System (2003) 有着里程碑式的意义,并由此诞生了Hadoop生态中HDFS的开源实现。笔者出于学习的目的,将此文章翻译成中文,其中部分地方会加上自己的理解和注释。前五章参考Praying的翻译。 1. 介绍(INTRODUCTION) 我们已经设计和实现了Google File System(GFS)来满足...
This paper presents and compares two common distributed processing frameworks involved in dealing with storage of large amounts of dataGoogle File System (More commonly now known as 'Colossus') and Hadoop Distributed File System. Also, it gives an insight to the MAPREDUCE framework common to both...