深入理解Java NIO:高效IO编程指南

需积分: 9 14 下载量 131 浏览量 更新于2024-07-18 收藏 2.74MB PDF 举报
"这是一本关于Java NIO的高清电子书,详细介绍了Java 1.4版本引入的新IO功能,特别是关于缓冲区的无阻塞IO技术。书籍由Ron Hitchens编写,由O'Reilly出版社出版。书中深入探讨了Java程序员在处理IO时遇到的常见挑战,并展示了如何利用新IO特性来提升代码效率。内容涵盖了如何解决实际的IO问题,以及新特性如何直接影响到响应速度、可扩展性和可靠性。由于NIO API是对1.3版本IO功能的补充,书里也会指导读者何时使用新API,何时应选择旧的1.3 IO API。" Java NIO(New IO)是Java平台中用于替代标准IO API的一套新API,它在Java 1.4版本中引入。NIO的核心特点是非阻塞I/O,这使得程序在等待数据准备就绪时不会被阻塞,从而提高了并发性能。在传统的IO模型中,读写操作通常是阻塞的,即在数据未准备好或无法写入时,程序会等待,这在高并发场景下可能会成为性能瓶颈。 NIO的关键组件包括: 1. **通道(Channels)**:通道是数据传输的入口和出口,它们连接到不同的数据源(如文件、套接字、内存等)。通道是双向的,可以进行读写操作。 2. **缓冲区(Buffers)**:缓冲区是数据的主要交互对象,数据在通道与应用程序之间通过缓冲区进行传输。缓冲区提供了更有效的方式管理数据,可以进行预读和后写操作。 3. **选择器(Selectors)**:选择器允许单线程监控多个通道的事件,如读、写、连接和关闭事件,这大大提升了处理大量连接的能力,特别适用于服务器端的高并发场景。 书中的内容可能还包括: - 对比传统IO和NIO的差异,解释为何在某些场景下NIO更为合适。 - 缓冲区的使用技巧,如如何创建、填充、清空和翻转缓冲区。 - 通道的类型,如FileChannel、SocketChannel和DatagramChannel,以及如何进行读写操作。 - 选择器的使用方法,如何注册通道、选择已就绪的通道以及处理各种IO事件。 - 非阻塞I/O的实现原理,包括异步I/O模型和多路复用I/O模型。 - 故障处理和性能优化策略,如何有效地利用NIO提升系统性能。 - 实战示例,展示如何在实际项目中应用NIO解决特定的IO问题。 通过阅读这本书,读者将能够全面理解Java NIO的原理和实践,从而在开发过程中更好地利用这一强大的工具。无论是对性能有苛刻要求的服务器端应用,还是需要高效处理大量数据的系统,掌握NIO都是至关重要的。
2011-12-13 上传
Java NIO.pdf Dedication ............................................................................................................................. 1 Preface .................................................................................................................................. 2 Organization...................................................................................................................... 3 Who Should Read This Book............................................................................................. 5 Software and Versions ....................................................................................................... 5 Conventions Used in This Book......................................................................................... 6 How to Contact Us ............................................................................................................. 7 Acknowledgments.............................................................................................................. 8 Chapter 1. Introduction..................................................................................................... 10 1.1 I/O Versus CPU Time ................................................................................................ 10 1.2 No Longer CPU Bound.............................................................................................. 11 1.3 Getting to the Good Stuff ........................................................................................... 12 1.4 I/O Concepts............................................................................................................... 13 1.5 Summary .................................................................................................................... 21 Chapter 2. Buffers .............................................................................................................. 22 2.1 Buffer Basics .............................................................................................................. 23 2.2 Creating Buffers ......................................................................................................... 36 2.3 Duplicating Buffers .................................................................................................... 38 2.4 Byte Buffers ............................................................................................................... 40 2.5 Summary .................................................................................................................... 52 Chapter 3. Channels........................................................................................................... 54 3.1 Channel Basics ........................................................................................................... 55 3.2 Scatter/Gather............................................................................................................. 62 3.3 File Channels.............................................................................................................. 67 3.4 Memory-Mapped Files............................................................................................... 80 3.5 Socket Channels ......................................................................................................... 91 3.6 Pipes ......................................................................................................................... 109 3.7 The Channels Utility Class....................................................................................... 114 3.8 Summary .................................................................................................................. 115 Chapter 4. Selectors ......................................................................................................... 117 4.1 Selector Basics ......................................................................................................... 117 4.2 Using Selection Keys ............................................................................................... 125 4.3 Using Selectors......................................................................................................... 128 4.4 Asynchronous Closability ........................................................................................ 137 4.5 Selection Scaling ...................................................................................................... 138 4.6 Summary .................................................................................................................. 143 Chapter 5. Regular Expressions ..................................................................................... 145 5.1 Regular Expression Basics ....................................................................................... 145 5.2 The Java Regular Expression API............................................................................ 147 5.3 Regular Expression Methods of the String Class..................................................... 168 5.4 Java Regular Expression Syntax .............................................................................. 169 5.5 An Object-Oriented File Grep.................................................................................. 172 5.6 Summary .................................................................................................................. 178 Chapter 6. Character Sets ............................................................................................... 180 6.1 Character Set Basics................................................................................................. 180 6.2 Charsets .................................................................................................................... 182