(Writing a Web Crawler by Yourself, Luo Gang and Wang Zhendong summarized the experience of the rabbit hunting search engineer project of Tsinghua University Press for many years, and deeply introduced the implementation process of Web data mining. The cases were written in popular Java language. This book introduces the key issues and Java implementation in the development of web crawlers, mainly including obtaining information from the Internet, obtaining information and mining Web information. This book is suitable for developers with a foundation in Java programming, and can also be used as a reference textbook for undergraduates or graduate students of computer related majors.)