【正文】 s the original XML document (the DTD has been omitted): …… Rename the file using a .jsp extension First, we need to rename the file with a .jsp extension so that the Web server will know what to do with the file. Web servers have rules for acting on certain URL patterns or file extensions, such as .html or .gif. When a Web application server is added to a Web server, the application server adds rules to the Web server39。s consider why you might want to create dynamic XML using JSP. Why not simply write a Java application or servlet to generate the entire document? Why bother with JSP at all? The most important reason, providing only portions of an XML document are dynamic, is that it makes sense not to regenerate that static content for every request. Using a JSP page, the static XML within the page acts as a template that is filled out by the dynamic content. Your Java code is tasked with generating only the content that might change over time a more efficient approach. As a practical matter, JSP pages allow you to separate tasks for which different developers will be responsible. In particular, they allow you to better separate the data from the view, allowing you to add new presentations without affecting the logic. Imagine having one Java servlet that performs the business logic and redirects the resulting data to an appropriate JSP page based on the nature of the request. For example, a servlet might redirect data to a JSP page containing WML when it detects a WAP phone browser making the request. It could also redirect the data to a JSP page containing HTML for standard browser requests. 大連民族學(xué)院計(jì)算機(jī)科學(xué)與工程系 2021 屆畢業(yè)論文 III The mechanics Let39。s extension: .jsp (not .html). The Web application server then preprocesses the JSP page, taking out the JSP tags and any embedded Java code, leaving only the HTML. The extracted JSP tags and embedded Java code are used to build a Java servlet (JSP page servlet) that runs the code and inserts the results back into the original page where the JSP tags used to be. The result is pure HTML. The Java is stripped out and run on the server before the requesting browser sees any result. We can apply the same principle to an XML page. Before the requester of the JSP page containing XML ever sees the XML (be it a browser or some other B2B application), the Java code is stripped out of the JSP page and used to generate additional content, which is inserted back into the page at the points where the JSP tags used to reside. This feature gives you the ability to control exactly where new content is to be inserted, down to the character. We39。re going to keep it 建立基于 Web 技術(shù)的郵件服務(wù)平臺(tái) 李治坤 II simple and focus on some of the basics. For more information, see Resources for links to additional JSP technology information. In the traditional sense, JSP pages look very much like HTML pages, with a few extra tags. These tags allow the designer to embed Java code (not JavaScript) in the page itself. A Web application server, like the IBM WebSphere Application Server, will intercept requests for JSP pages. It39。s relatively simple. You can build a JSP page using an XML document that will serve as the template for the output, then replace the portions that must be generated dynamically based on the underlying business logic. You use Java code, either written directly within the JSP page or called externally from the page, to generate the dynamic portions of the document. You are in control of how much of that document is generated. For example, you can use Java code to generate data between XML tags, to generate portions of the XML document tree (both tags and data), or even to generate the entire document. The Java code is removed from the page, processed into a servlet (known as the page servlet) and run by the Java application server as part of the request for the JSP page. The result is pure XML. A JSP technology overview Let39。在此我要感謝楊老師的悉心關(guān)懷和耐心的指導(dǎo)，向楊老師致以誠(chéng)摯的協(xié)議和美好的祝愿！同時(shí)我還有感謝我的同學(xué)和朋友在諸多方面給我的幫助和支持。 計(jì)算機(jī)系 001 李治坤 2021 年 6 月大連民族學(xué)院計(jì)算機(jī)科學(xué)與工程系 2021 屆畢業(yè)論文 25 致謝 畢業(yè)設(shè)計(jì)雖然只有短短的三個(gè)月，但是它具有獨(dú)特的挑戰(zhàn)性，要在這三個(gè)月中開(kāi)發(fā)一個(gè)郵件服務(wù)平臺(tái)，對(duì)于一個(gè)從未從事過(guò)這項(xiàng)工作的大學(xué)商來(lái)說(shuō)并不是一件容易的事。正因?yàn)槿绱宋以谶x題上盡可能的讓所做的題目涵蓋大學(xué)四年所學(xué)的所有知識(shí)點(diǎn)，包括成軟件工程，程序設(shè)計(jì)，網(wǎng)絡(luò)應(yīng)用，操作系統(tǒng)等等。其穩(wěn)定性，運(yùn)行速度，還是所能承受的負(fù)載都能夠滿(mǎn)足中小型企業(yè)需求。 本系統(tǒng)開(kāi)發(fā)使用了當(dāng)今 JSP Web 應(yīng)用開(kāi)發(fā)最流行的 Servlet 技術(shù)，將網(wǎng)頁(yè)代碼和 Java 代碼分開(kāi)處理，系統(tǒng)還使用了符合 J2EE 標(biāo)準(zhǔn)的 Java Mail API 這使得 整個(gè)系統(tǒng)有良好的可擴(kuò)展性和可維護(hù)性，為產(chǎn)品日后的維護(hù)和再次開(kāi)發(fā)提供了很有利的條件。用戶(hù)所選擇的地址將會(huì)通過(guò)一個(gè)Session 返回到編輯界面地址的輸入欄。通過(guò)這種方法可以直接使用 SQL 語(yǔ)句進(jìn)行數(shù)據(jù)庫(kù)的操作，將返回的值格式化以后就可以直接使用 。這個(gè)程序主要是對(duì) WebMail數(shù)據(jù)庫(kù) addrlist 表的操作。通過(guò)大連民族學(xué)院計(jì)算機(jī)科學(xué)與工程系 2021 屆畢業(yè)論文 23 () 方 法 取 得 Multipart 的 每 一 部 分 ， 通 過(guò)()來(lái)去的附件的意向和內(nèi)容類(lèi)型并據(jù)此加以處理。 當(dāng)一個(gè)郵件包含有附件時(shí)，郵件的內(nèi)容是 Multipart，而不是 Part 對(duì)象。獲得數(shù)據(jù)資源后，在調(diào)用 setDataHandler()函數(shù)粘貼到 BodyPart 之前，必須傳遞到 DataHandler 構(gòu)造其中。附件是文件時(shí)，數(shù)據(jù)資源是 FileDataSource。在讀取程序中我也使用到 getMessages()方法，這樣可以確定所要讀取的郵件時(shí)那一封，同時(shí)也可以防止用戶(hù)選擇了不存在的郵件。該程序所使用的方法和 類(lèi)似。然后分別用setFrom(fromID) 、 setRecipients(,iAddr) 、setSubject(subject)、 setText(text)將相對(duì)應(yīng)的內(nèi)容添加到表單中，再使用 把郵件發(fā)送出去。在定義變量的時(shí)候需要將 subject 和 messageText 用 getByte(“ISO8859_1”)方法將字符轉(zhuǎn)化為郵件服務(wù)器能夠識(shí)別的字符。 4． 3． 3 郵件編輯界面 郵件的編輯界面是 基調(diào)用的 servlet是 。通過(guò)調(diào)用 Java Mail API 中提供的 Floder 類(lèi)，使用 getFolder()方法定義一個(gè) Folder 變量 folder，使用 ()設(shè)置目錄的打開(kāi)方式為只讀，用 ()方法可以獲得郵箱中的郵件數(shù)量，建立一個(gè)數(shù)組 message[]來(lái)定位郵件。 要連接郵件的存儲(chǔ)，然后打開(kāi)名為 INBOX 的文件夾。 4． 3． 2 郵件列表界面 當(dāng)用戶(hù)順利登錄系統(tǒng)后會(huì)進(jìn)入系統(tǒng)的歡迎界面，用戶(hù)點(diǎn)擊框架右邊的收件箱就可以進(jìn)入郵件列表界面。這兩個(gè) servlet 所使用的方法和 中所使用的方法類(lèi)似。用戶(hù)密碼找回 界面和用戶(hù)注冊(cè)界面分別是 和 。在 中通過(guò)拋出ServletException 類(lèi)來(lái)處理與數(shù)據(jù)庫(kù)的連接。然后對(duì) logname 和 logpass 進(jìn)行分析，如為空則給出提示要用戶(hù)輸入用戶(hù)名和密碼。 servlet，它利用 類(lèi)庫(kù)提供 的 HttpServlet 接口建立與 Web 服務(wù)器的連接。 生成用戶(hù)登錄信息的表單。 圖（ 8） WebMail 數(shù)據(jù)庫(kù)中的 addrlist 表 member 表的數(shù) 據(jù)在用戶(hù)注冊(cè)和用戶(hù)登錄進(jìn)行身份認(rèn)證的時(shí)候被使用， addrlist 表的數(shù)據(jù)在用戶(hù)選擇收件人的操作時(shí)被使用，在該郵件系統(tǒng)中沒(méi)有能將兩張表聯(lián)系起來(lái)的操作，所以?xún)蓮埍硐鄬?duì)對(duì)立。 addruser：儲(chǔ)存的地址所對(duì)應(yīng)的聯(lián)系人。 userID：儲(chǔ)存該地址的用戶(hù)，不能為空。 圖（ 7） WebMail 數(shù)據(jù)庫(kù)中的 member 表 第二 張表是 addrlist 表，用來(lái)保存用戶(hù)的 地址簿 信息。 Hobbies：用戶(hù)的愛(ài)好。 Province：用戶(hù)所在