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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 ...

Http://www.aliyun.com/zixun/aggregation/14223.html "> Application system, the log is an indispensable important part of all the application of error information should be able to find in the log file, 　　Some application system log may be very small, some large application system log is quite large, while the log file must be user-friendly and search, to have a high performance, otherwise it will affect the performance of the application system. Because the log usually involves I.

1. Prepare to work, after installing good habse, execute hbase Shell create ' table name ', ' column name 1 ', ' Column Name 2 ', ' Column name n ' create ' table name ', ' column family name ' in HBase column can be dynamically added, only need to have a row family on it Create ' Test_lcc_person ', ' Lcc_liezu ' and then add some data key the same is a piece of data, a total of 6 data put ' table name ', ' Rowk ...

I. Build HADOOP development environment The various code that we have written in our work is run in the server, and the HDFS operation code is no exception. During the development phase, we used eclipse under Windows as the development environment to access the HDFs running in the virtual machine. That is, accessing HDFs in remote Linux through Java code in local eclipse. To access the HDFS in the client computer using Java code from the host, you need to ensure the following: (1) Ensure host and client ...

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 ...

Hadoop is a Java implementation of Google MapReduce. MapReduce is a simplified distributed programming model that allows programs to be distributed automatically to a large cluster of ordinary machines. Just as Java programmers can do without memory leaks, MapReduce's run-time system solves the distribution details of input data, executes scheduling across machine clusters, handles machine failures, and manages communication requests between machines. This ...

Hadoop is a Java implementation of Google MapReduce. MapReduce is a simplified distributed programming model that allows programs to be distributed automatically to a large cluster of ordinary machines. Just as Java programmers can do without memory leaks, MapReduce's run-time system solves the distribution details of input data, executes scheduling across machine clusters, handles machine failures, and manages communication requests between machines. Such a pattern allows programmers to not need ...

Hadoop is a Java implementation of Google MapReduce. MapReduce is a simplified distributed programming model that allows programs to be distributed automatically to a large cluster of ordinary machines. Just as Java programmers can do without memory leaks, MapReduce's run-time system solves the distribution details of input data, executes scheduling across machine clusters, handles machine failures, and manages communication requests between machines. Such a pattern allows programmers to be able to do nothing and ...

In the past few years, the innovative development of the open source world has elevated the productivity of Java™ developers to one level. Free tools, frameworks and solutions make up for once-scarce vacancies. The Apache CouchDB, which some people think is a WEB 2.0 database, is very promising. It's not difficult to master CouchDB, it's as simple as using a Web browser. This issue of Java open ...