【導讀】JSP開發(fā)人員構建Web應用程序時遇到需要強大的數據庫連接的特殊問題。上的發(fā)展模式為基礎的挑戰(zhàn)。據庫開發(fā)-JavaServer頁面，JDBC和數據庫模式所需的核心技術概述。規(guī)則，并平衡服務器上的用戶負載的概念。人員能夠與大多數商業(yè)數據庫如Oracle進行溝通。在MySQL和JSP的Web應用。惠的方式來測試書中的例子的應用程序和試驗。JSP是所有關于做高度面向對象的網站，可以利用所有的現代軟件工程最。是萬能的而且使用它會自動將您的網站上的工程藝術的典范。你會看到如何合并最佳方法以及項目得到的壓力時候如何避免方便的陷阱。引擎能夠熟悉網頁的的少了一個Java組件的Web服務器。JSP是由Javaservlet發(fā)展演變而來的。servlet允許開發(fā)人員處理傳入使。此外，該servlet可以訪問會話持久對象。定的用戶會話，可用于存儲請求之間的狀態(tài)對象。發(fā)人員編寫結構良好的模塊化的Web應用程序使用面向對象語言的重要一步。Servlet還遭受一大問題。此外，必須避免所。訂單需要履行，訂單已發(fā)貨，并已待補物品。

　　

【正文】 ns is (in my opinion) important enough to make sure that you have it available. Rollback allows you to set a savepoint on the database before starting to do a series of transactions with it, and be able to either roll back to the original state or mit the changes at the end. For example, when recording a purchase, you need to record a debit against the user39。s account and enter a record into the shipping table so that you39。ll know later to ship the item. Let39。s say that the second part fails. You wouldn39。t want to charge the user but not ship the item. Thus, you39。d want to roll back to the state before the transaction began. So, MySQL isn39。t a fullblown production database— at least, not yet. It39。s still good enough for probably 90% of the emerce sites in the world, however. And version , which is in alpha as of this writing, addresses a number of these concerns, including rowlevel locking and transaction control. Putting Tomcat and MySQL Together Combining Tomcat and MySQL provides a powerful, reliable, and free platform that you can use to learn, develop, and deploy JSP applications. And, best of all, the code that you develop using this platform will run nicely using iPla and Oracle or WebSphere and SQL Server. As a learning tool the two together are almost reference implementations of their respective protocols (JSP and SQL). As a result, you won39。t pick up any nasty vendorproprietary bad habits while you39。re getting up to speed. In addition, you can enjoy the knowledge that you are supporting the opensource software movement. Opensource software is code that is made freely available under one of several public licenses, frequently the GNU General Public License (GPL). FACTS AND FICTION ABOUT THE GPL The GNU General Public License is probably one of the most misunderstood documents in existence,The basics break down to this: 1. If you place a piece of software under the GPL, anyone is free to make a copy of it in either source or executable form and give it to anyone else. 2. If you take a piece of software under the GPL and use it as a part of your product, you can39。t charge for that product beyond duplication costs. Many people interpret this to mean that they can39。t use GPL software for mercial purposes. Nothing is farther from the truth. What you can39。t do is charge specifically for parts of your product that are partly or largely derived from GPL products. You are free to use GPL code in the development of a Web site because you39。re not selling the site itself to a third party as a product. (Consulting panies fall into a weird quasispace, but no one has gone after them for using GPL software to date.) Why is it good to support this movement? There are two sides to this answer: one technical and one political. Technically, it39。s a good thing because opensource software tends to encourage the development of open standards such as JSP and JDBC, allowing you to choose your tools from among a larger group rather than being locked into one vendor39。s proprietary solution. It39。s a positive thing politically because it keeps the large panies honest. WebLogic and iPla have to stay petitive and responsive because they know that there39。s a free solution out there if they aren39。t. And when you use opensource software, you are sending a message that your overriding concerns are features and reliability, not having a large pany to sue if something goes wrong.