String Byte Size

This is a PHP string truncation function Oh, this is a Chinese string support oh, it can intercept html and Chinese and Western mixed content, and the html tag is not Count in the character interception, if the html tag is not closed, the program will automatically filter extra tags. * / function mysubstr ($ str, $ length) {$ ...

Hadoop serialization and Writable Interface (i) introduced the Hadoop serialization, the Hadoop writable interface and how to customize your own writable class, and in this article we continue to introduce the Hadoop writable class, 　　This time we are concerned about the length of bytes occupied after the writable instance was serialized, and the composition of the sequence of bytes after the writable instance was serialized. Why to consider the byte length of the writable class large data program ...

1. Boxing, unpacking or aliases many of the introduction of C #. NET learning experience books on the introduction of the int-> Int32 is a boxing process, the reverse is the process of unpacking. This is true of many other variable types, such as short <-> int16,long <->int64. For the average programmer, it is not necessary to understand this process, because these boxes and unboxing actions can be automatically completed, do not need to write code to intervene. But we need to remember that ...

There's a whole bunch of files. How do we find what we need, and the way to do that is to find the corresponding directory. Open the directory. Traverse all files. Each file is scanned again if it contains a display and does not continue looking until the end. Paging file (allfile.php) <div id= "Checkarea" > <h2>just Check it!</h2> <fo ...

This article is my second time reading Hadoop 0.20.2 notes, encountered many problems in the reading process, and ultimately through a variety of ways to solve most of the. 　　Hadoop the whole system is well designed, the source code is worth learning distributed students read, will be all notes one by one post, hope to facilitate reading Hadoop source code, less detours. 1 serialization core Technology The objectwritable in 0.20.2 version Hadoop supports the following types of data format serialization: Data type examples say ...

This paper is an excerpt from the book "The Authoritative Guide to Hadoop", published by Tsinghua University Press, which is the author of Tom White, the School of Data Science and engineering, East China Normal University. This book begins with the origins of Hadoop, and integrates theory and practice to introduce Hadoop as an ideal tool for high-performance processing of massive datasets. The book consists of 16 chapters, 3 appendices, covering topics including: Haddoop;mapreduce;hadoop Distributed file system; Hadoop I/O, MapReduce application Open ...

There is a concept of an abstract file system in Hadoop that has several different subclass implementations, one of which is the HDFS represented by the Distributedfilesystem class. In the 1.x version of Hadoop, HDFS has a namenode single point of failure, and it is designed for streaming data access to large files and is not suitable for random reads and writes to a large number of small files. This article will explore the use of other storage systems, such as OpenStack Swift object storage, as Ha ...

MapReduce: Simple data processing on large cluster

Blog Description: 1, research version hbase 0.94.12;2, posted source code may be cut, only to retain the key code. 　　Discusses the HBase write data process from the client and server two aspects. One, client-side 1, write data API write data is mainly htable and batch write two API, the source code is as follows://write the API public void to put ("final") throws IO ...

Hadoop streaming is a multi-language programming tool provided by Hadoop that allows users to write mapper and reducer processing text data using their own programming languages such as Python, PHP, or C #. Hadoop streaming has some configuration parameters that can be used to support the processing of multiple-field text data and participate in the introduction and programming of Hadoop streaming, which can be referenced in my article: "Hadoop streaming programming instance". However, with the H ...