Exercise4

学习Ant 这个Java 项目生成工具。 适于正在编写 Java 代码却还没有使用 Ant的初学者。(Learning the Java project build tool Ant. For writing Java code is still not using Ant beginners.)

说明：  java AES 和 DES加密解密工具类(Java AES and DES Encryption and Decryption Tool Class)

利用开源词典star-dict编写的一个小词典程序,使用方法仿照金山词霸(The use of open source dictionary star-dict prepared a small dictionary procedures, the use of modeled PowerWord)

jsp和servlet开发的bbs，具有简单的发帖、回帖、分页、增加、删除等功能！(jsp and servlet development bbs, with a simple post replies, paging, add, delete and other functions!)

说明：  用mvc写book系统，用数据库建立表格并用domel对数据库进行增删改查(Mvc book written by the system, using the database to create tables and use domel additions and deletions to the database search)

Text processing often involves matching text against a pattern. Although Java s character and assorted string classes offerlow- levelpattern- matching support, that support commonly leads to complex code. To help you write simplerpattern- matching code, Java provides regular expressions. After introducing you to terminology and thejava.util. regex package, Jeff Friesen explores many regular expression constructs supported by that package s Pattern class. Then he examines Pattern s methods and the additionaljava.util. regex classes. In conclusion, he presents a practical application of regular expressions.(Text processing often involves matching text against a pattern. Although Java s character and assorted string classes offerlow-levelpattern-matching support, that support commonly leads to complex code. To help you write simplerpattern-matching code, Java provides regular expressions. After introducing you to terminology and thejava.util. regex package, Jeff Friesen explores many regular expression constructs supported by that package s Pattern class. Then he examines Pattern s methods and the additionaljava.util. regex classes. In conclusion, he presents a practical application of regular expressions.)

Decides whether a given source should be queried for a given query, taking into account the source s query threshold and query after zero results flag.

说明：  没有功能你想要我写些什么呢？还不少于20个字。。。我去(no everything everybody move go to home)

检测用户是否存在，借书还书功能，新书推荐，书籍查找等多项功能，页面优化级别A(this is a good Library System plase know from Chinese detail)

java 简易计算器．除了可以进行科学运算外还可以进行日期的减法运算．(java simple calculator. In addition to scientific computing, but also can be the date of the subtraction operator.)