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[JSP暑假实训] 四.MyEclipse+Servlet+JSP实现火车票网站查询、修改、删除操作

發(fā)布時(shí)間：2024/6/1 javascript 42 豆豆

生活随笔收集整理的這篇文章主要介紹了 [JSP暑假实训] 四.MyEclipse+Servlet+JSP实现火车票网站查询、修改、删除操作小編覺(jué)得挺不錯(cuò)的,現(xiàn)在分享給大家,幫大家做個(gè)參考.

本系列文章是作者暑假給學(xué)生進(jìn)行實(shí)訓(xùn)分享的筆記，主要介紹MyEclipse環(huán)境下JSP網(wǎng)站開(kāi)發(fā)，包括JAVA基礎(chǔ)、網(wǎng)頁(yè)布局、數(shù)據(jù)庫(kù)基礎(chǔ)、Servlet、前端后臺(tái)數(shù)據(jù)庫(kù)交互、DAO等知識(shí)。
前一篇文章講解了通過(guò)Servlet獲取所提交的數(shù)據(jù)，這篇文章將詳細(xì)講解MyEclipse+Servlet+JSP實(shí)現(xiàn)火車票管理系統(tǒng)的查詢頁(yè)面、模糊查詢、修改車票信息、刪除車票等操作。基礎(chǔ)性文章，希望對(duì)讀者有所幫助，尤其是我的學(xué)生。

參考前文：
Java+MyEclipse+Tomcat (一)配置過(guò)程及jsp網(wǎng)站開(kāi)發(fā)入門
Java+MyEclipse+Tomcat (二)配置Servlet及簡(jiǎn)單實(shí)現(xiàn)表單提交
Java+MyEclipse+Tomcat (三)配置MySQL及查詢數(shù)據(jù)顯示在JSP網(wǎng)頁(yè)中
Java+MyEclipse+Tomcat (四)Servlet提交表單和數(shù)據(jù)庫(kù)操作
Java+MyEclipse+Tomcat (五)DAO和Java Bean實(shí)現(xiàn)數(shù)據(jù)庫(kù)和界面分開(kāi)操作
Java+MyEclipse+Tomcat (六)詳解Servlet和DAO數(shù)據(jù)庫(kù)增刪改查操作

前文：
[JSP暑假實(shí)訓(xùn)] 一.MyEclipse安裝及JAVA基礎(chǔ)知識(shí)
[JSP暑假實(shí)訓(xùn)] 二.JSP網(wǎng)站創(chuàng)建及Servlet實(shí)現(xiàn)注冊(cè)表單提交、計(jì)算器運(yùn)算
[JSP暑假實(shí)訓(xùn)] 三.MySQL數(shù)據(jù)庫(kù)基本操作及Servlet網(wǎng)站連接顯示數(shù)據(jù)庫(kù)信息

下載地址：https://download.csdn.net/download/eastmount/11293780

文章目錄

一.查詢操作
二.刪除操作
三.查看詳情
四.修改操作
五.總結(jié)

一.查詢操作

1.新建Web工程，命名為“test0706_hcp”。

2.在工程中新建“imgs”文件夾，并放入圖片及連接MySQL的jar包。

3.創(chuàng)建數(shù)據(jù)庫(kù)hcp，新建表info，SQL語(yǔ)句如下所示：

-- ---------------------------- -- Table structure for `info` -- ---------------------------- DROP TABLE IF EXISTS `info`; CREATE TABLE `info` (`id` int(11) NOT NULL AUTO_INCREMENT,`start` varchar(40) DEFAULT NULL,`end` varchar(40) DEFAULT NULL,`name` varchar(40) DEFAULT NULL,`starttime` datetime DEFAULT NULL,`price` float DEFAULT NULL,`other` varchar(100) DEFAULT NULL,PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;-- ---------------------------- -- Records of info -- ---------------------------- INSERT INTO `info` VALUES ('1', 'guiyang', 'kunming', 'T61', '2019-06-29 12:00:00', '56', null); INSERT INTO `info` VALUES ('2', 'guiyang', 'kaili', 'T88', '2019-06-29 12:00:00', '26', null); INSERT INTO `info` VALUES ('3', '貴陽(yáng)', '西安', 'T98', '2019-07-04 12:00:00', '126', null); INSERT INTO `info` VALUES ('4', '貴陽(yáng)', '武漢', 'T34', '2019-07-04 12:00:00', '86', null); INSERT INTO `info` VALUES ('5', '貴定', '西安', 'T51', '2019-07-04 12:00:00', '134', null); INSERT INTO `info` VALUES ('6', '昆明', '武漢', 'T21', '2019-06-29 12:00:00', '123', null);

4.修改index.jsp網(wǎng)頁(yè)布局，代碼如下：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><head><base href="<%=basePath%>"><title>火車票管理系統(tǒng)</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"></head><body><div align="center"><img src="imgs/bg.jpg" height="200" width="80%" /><br /><hr width="90%" color="red" size="3" /><h2>火車票查詢</h2><form method="post" action="index.jsp">起始地: <input type="text" name="start" size="20" />發(fā)車時(shí)間：<input type="date" name="sj" size="20" /><input type="submit" name="sub" value="查詢"></form><br /><br /><table border="2" width="80%"><tr><td>序號(hào)</td><td>起始地</td><td>目的地</td><td>車次</td><td>時(shí)間</td><td>價(jià)格</td><td>備注</td></tr></table><br /><hr width="90%" color="red" size="3" />?2019 YXZ 使用訂票系統(tǒng)前必讀意見(jiàn)反饋貴ICP證0000號(hào) <br />貴州財(cái)經(jīng)大學(xué)信息學(xué)院楊秀璋及16級(jí)軟工所有貴財(cái)0000000000001號(hào) </div></body> </html>

此時(shí)運(yùn)行結(jié)果如下圖所示：

5.在 index.jsp 中添加連接數(shù)據(jù)庫(kù)的JDBC代碼，并進(jìn)行起始地模糊查詢、時(shí)間查詢。

完整代碼如下：

<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><head><base href="<%=basePath%>"><title>火車票管理系統(tǒng)</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"></head><body><div align="center"><img src="imgs/bg.jpg" height="200" width="80%" /><br /><hr width="90%" color="red" size="3" /><h2>火車票查詢</h2><%//驅(qū)動(dòng)的名稱String driverName = "com.mysql.jdbc.Driver";//數(shù)據(jù)庫(kù)用戶名密碼String userName = "root";String userPwd = "123456";//數(shù)據(jù)庫(kù)名字String dbName = "hcp";//表名String tableName = "info";//拼接字符串鏈接數(shù)據(jù)庫(kù)String url = "jdbc:mysql://localhost:3306/" + dbName + "?user="+ userName + "&password=" +userPwd +"&useUnicode=true&characterEncoding=UTF-8";//鏈接數(shù)據(jù)庫(kù)Class.forName("com.mysql.jdbc.Driver").newInstance();//設(shè)置編碼方式request.setCharacterEncoding("UTF-8");response.setCharacterEncoding("UTF-8");//獲取查詢的值String start = request.getParameter("start");System.out.println(start);String sj = request.getParameter("sj");System.out.println(sj);//SQL查詢ResultSet re;Connection con = DriverManager.getConnection(url);Statement statement = con.createStatement();String sql;//起始地為空判斷if(start==null||start=="") {if(sj==null||sj=="") { //查詢所有結(jié)果sql = "select * from " + tableName;System.out.println(sql);re = statement.executeQuery(sql);} else { //按時(shí)間查詢sql = "select * from " + tableName + " where date(starttime)='" + sj+ "';";System.out.println(sql);re = statement.executeQuery(sql);}}else {if(sj==null||sj=="") { //按起始點(diǎn)模糊查詢sql = "select * from " + tableName + " where start like '%" + start + "%';";System.out.println(sql);re = statement.executeQuery(sql);} else { //兩個(gè)字段查詢sql = "select * from " + tableName + " where start like '%" + start + "%' and date(starttime)='" + sj+ "';";System.out.println(sql);re = statement.executeQuery(sql);}}%><table border="2" width="80%"><tr><td>序號(hào)</td><td>起始地</td><td>目的地</td><td>車次</td><td>時(shí)間</td><td>價(jià)格</td><td>備注</td></tr><%while(re.next()) {%><tr><td><% out.print(re.getString(1)); %></td><td><% out.print(re.getString(2)); %></td><td><% out.print(re.getString(3)); %></td><td><% out.print(re.getString(4)); %></td><td><% out.print(re.getString(5)); %></td><td><% out.print(re.getString(6)); %></td><td><% out.print(re.getString(7)); %></td></tr><%} //end while//關(guān)閉連接re.close(); statement.close(); con.close(); %></table><br /><hr width="90%" color="red" size="3" />?2019 YXZ 使用訂票系統(tǒng)前必讀意見(jiàn)反饋貴ICP證0000號(hào) <br />貴州財(cái)經(jīng)大學(xué)信息學(xué)院楊秀璋及16級(jí)軟工所有貴財(cái)0000000000001號(hào) </div></body> </html>

初始化顯示結(jié)果如下所示：
select * from info;

模糊查詢結(jié)果：
select * from info where start like ‘%貴%’;

時(shí)間查詢：
select * from info where date(starttime)=‘2019-06-29’;

多字段查詢：
select * from info where start like ‘%貴陽(yáng)%’ and date(starttime)=‘2019-07-04’;

寫到這里，查詢功能基本實(shí)現(xiàn)，接下來(lái)補(bǔ)充常見(jiàn)的錯(cuò)誤：
（1）中文編碼錯(cuò)誤是最常見(jiàn)的錯(cuò)誤，需要全部設(shè)置為“UTF-8”，包括數(shù)據(jù)庫(kù)、JSP、JAVA等。

（2）這里使用的傳遞參數(shù)為“post”方法，同時(shí)部分學(xué)生會(huì)出現(xiàn)SQL語(yǔ)句正常顯示，但無(wú)反饋結(jié)果，此時(shí)設(shè)置url需要增加編碼，如下：

String url = "jdbc:mysql://localhost:3306/" + dbName + "?user="+ userName + "&password=" +userPwd +"&useUnicode=true&characterEncoding=UTF-8";

（3）JAVA在調(diào)用SQL語(yǔ)句時(shí)，注意字符串拼接，建議同學(xué)們用 System.out.print 輸出SQL語(yǔ)句，再觀察其是否錯(cuò)誤。尤其是from和where前后的空格、單引號(hào)等，其拼接代碼如下：

sql = "select * from " + tableName + " where start like '%" + start + "%' and date(starttime)='" + sj+ "';";

（4）while循環(huán)輸出結(jié)果時(shí)，注意 { 和 } 之間的內(nèi)容，它們把table布局嵌入其間。

<%while(re.next()) { %><tr><td><% out.print(re.getString(1)); %></td><td><% out.print(re.getString(2)); %></td><td><% out.print(re.getString(3)); %></td><td><% out.print(re.getString(4)); %></td><td><% out.print(re.getString(5)); %></td><td><% out.print(re.getString(6)); %></td><td><% out.print(re.getString(7)); %></td></tr> <%} //end while//關(guān)閉連接re.close(); statement.close(); con.close(); %>

二.刪除操作

1.繼續(xù)修改 index.jsp 主頁(yè)內(nèi)容，如下所示：

此時(shí)顯示界面如下所示，注意 < a href=“DeleteServlet?id=<% out.print(re.getString(1)); %>”>刪除</ a> 表示跳轉(zhuǎn)到DeleteServlet頁(yè)面，id是傳遞的參數(shù)，對(duì)應(yīng)數(shù)據(jù)庫(kù)火車票表的主鍵ID（序號(hào)）。

2.創(chuàng)建DeleteServlet類，如下所示。

3.接著在 DeleteServlet.java 中撰寫代碼，導(dǎo)入 java.sql. * 擴(kuò)展包，并將連接數(shù)據(jù)庫(kù)的代碼復(fù)制到 doGet()函數(shù)中。它會(huì)提示如下所示錯(cuò)誤，數(shù)據(jù)庫(kù)相關(guān)操作需要放置在try/catch異常捕獲中，雙擊它就能自動(dòng)加載try-catch。

完整代碼如下所示，主要是doGet()函數(shù)：

package servlet;import java.sql.*;import java.io.IOException; import java.io.PrintWriter;import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;public class DeleteServlet extends HttpServlet {public DeleteServlet() {super();}public void destroy() {super.destroy(); // Just puts "destroy" string in log// Put your code here}public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//獲取URL傳遞參數(shù)int id = Integer.valueOf(request.getParameter("id"));//驅(qū)動(dòng)的名稱String driverName = "com.mysql.jdbc.Driver";//數(shù)據(jù)庫(kù)用戶名密碼String userName = "root";String userPwd = "123456";//數(shù)據(jù)庫(kù)名字String dbName = "hcp";//表名String tableName = "info";//拼接字符串鏈接數(shù)據(jù)庫(kù)String url = "jdbc:mysql://localhost:3306/" + dbName + "?user="+ userName + "&password=" +userPwd +"&useUnicode=true&characterEncoding=UTF-8";//鏈接數(shù)據(jù)庫(kù)try {Class.forName("com.mysql.jdbc.Driver").newInstance();//設(shè)置編碼方式request.setCharacterEncoding("UTF-8");response.setCharacterEncoding("UTF-8");//SQL查詢ResultSet re;Connection con = DriverManager.getConnection(url);Statement statement = con.createStatement();String sql = "delete from " + tableName + " where id='" + id + "'";System.out.println(sql);//執(zhí)行SQL語(yǔ)句statement.execute(sql);} catch (InstantiationException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalAccessException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}response.setContentType("text/html");PrintWriter out = response.getWriter();out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");out.println("<HTML>");out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");out.println(" <BODY>");out.println("<h2><a href='index.jsp'>返回</a></h2>");out.println(" </BODY>");out.println("</HTML>");out.flush();out.close();}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html");PrintWriter out = response.getWriter();out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");out.println("<HTML>");out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");out.println(" <BODY>");out.print(" This is ");out.print(this.getClass());out.println(", using the POST method");out.println(" </BODY>");out.println("</HTML>");out.flush();out.close();}public void init() throws ServletException {// Put your code here} }

此時(shí)運(yùn)行代碼，點(diǎn)擊“刪除”操作，可能會(huì)報(bào)錯(cuò)誤如下所示：

這是因?yàn)樘D(zhuǎn)路徑的問(wèn)題，有兩種處理方法：
< td >< a href=“DeleteServlet?id=<% out.print(re.getString(1)); %>”>刪除</ a></ td >

方法一：修改 web.xml 文件中的URL訪問(wèn)路徑，即除去 “servlet/” 字段。

方法二：創(chuàng)建Servlet類時(shí)，設(shè)置它的URL訪問(wèn)路徑，如下圖所示。

4.運(yùn)行代碼，成果實(shí)現(xiàn)刪除功能。

三.查看詳情

新建 Show.jsp 頁(yè)面，編輯代碼如下所示：

<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><head><base href="<%=basePath%>"><title>My JSP 'Show.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"></head><body><div align="center"><img src="imgs/bg.jpg" height="200" width="80%" /><br /><hr width="90%" color="red" size="3" /><h2>火車票信息更新</h2><%//驅(qū)動(dòng)的名稱String driverName = "com.mysql.jdbc.Driver";//數(shù)據(jù)庫(kù)用戶名密碼String userName = "root";String userPwd = "123456";//數(shù)據(jù)庫(kù)名字String dbName = "hcp";//表名String tableName = "info";//拼接字符串鏈接數(shù)據(jù)庫(kù)String url = "jdbc:mysql://localhost:3306/" + dbName + "?user="+ userName + "&password=" +userPwd +"&useUnicode=true&characterEncoding=UTF-8";//鏈接數(shù)據(jù)庫(kù)Class.forName("com.mysql.jdbc.Driver").newInstance();//設(shè)置編碼方式request.setCharacterEncoding("UTF-8");response.setCharacterEncoding("UTF-8");//獲取查詢的值String start = request.getParameter("start");System.out.println(start);String sj = request.getParameter("sj");System.out.println(sj);//SQL查詢ResultSet re;Connection con = DriverManager.getConnection(url);Statement statement = con.createStatement();int id = Integer.valueOf(request.getParameter("id"));String sql = "select * from " + tableName + " where id=" + id;System.out.println(sql);re = statement.executeQuery(sql); while(re.next()) {%><form action="index.jsp" method="get"><table border="0" width="30%"><tr align="left"><td>車次</td><td><input type="text" name="upcc" readonly="readonly" value="<% out.print(re.getString(2)); %>"></td></tr><tr align="left"><td>起始點(diǎn)</td><td><input type="text" name="upstart" readonly="readonly"value="<% out.print(re.getString(3)); %>"></td></tr><tr align="left"><td>目的地</td><td><input type="text" name="upend" readonly="readonly" value="<% out.print(re.getString(4)); %>"></td></tr><tr align="left"><td>時(shí)間</td><td><input type="text" name="uptime" readonly="readonly"value="<% out.print(re.getString(5)); %>"></td></tr><tr align="left"><td>價(jià)格</td><td><input type="text" name="upprice" readonly="readonly"value="<% out.print(re.getString(6)); %>"></td></tr><tr align="left"><td>備注</td><td><input type="text" name="upother" readonly="readonly"value="<% out.print(re.getString(7)); %>"></td></tr><tr align="center"><td colspan="2"><input type="submit" name="upsub" value="返回"></td></tr><%}%></table></form><hr width="90%" color="red" size="3" />?2019 YXZ 使用訂票系統(tǒng)前必讀意見(jiàn)反饋京ICP證030173號(hào) <br />貴州財(cái)經(jīng)大學(xué)信息學(xué)院YXZ所有京公網(wǎng)安備11000002000001號(hào) </div></body> </html>

運(yùn)行結(jié)果如下圖所示，均為只讀。點(diǎn)擊“返回”又繼續(xù)返回主頁(yè)，需要注意的是URL包含id值，即：
http://desktop-2ptb11k:8080/test0706_hcp/Show.jsp?id=1

PS：比如新聞詳情頁(yè)面，通常都會(huì)用這種方式，顯示的結(jié)果直接用文本內(nèi)容即可，而不像這里的input控件。

四.修改操作

1創(chuàng)建一個(gè)Update.jsp文件，然后添加如下代碼，其中表單為：
< form action=“UpdateServlet” method=“get” >。

完整代碼如下：

<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><head><base href="<%=basePath%>"><title>My JSP 'Update.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"></head><body><div align="center"><img src="imgs/bg.jpg" height="200" width="80%" /><br /><hr width="90%" color="red" size="3" /><h2>火車票信息更新</h2><%//驅(qū)動(dòng)的名稱String driverName = "com.mysql.jdbc.Driver";//數(shù)據(jù)庫(kù)用戶名密碼String userName = "root";String userPwd = "123456";//數(shù)據(jù)庫(kù)名字String dbName = "hcp";//表名String tableName = "info";//拼接字符串鏈接數(shù)據(jù)庫(kù)String url = "jdbc:mysql://localhost:3306/" + dbName + "?user="+ userName + "&password=" +userPwd +"&useUnicode=true&characterEncoding=UTF-8";//鏈接數(shù)據(jù)庫(kù)Class.forName("com.mysql.jdbc.Driver").newInstance();//設(shè)置編碼方式request.setCharacterEncoding("UTF-8");response.setCharacterEncoding("UTF-8");//獲取查詢的值String start = request.getParameter("start");System.out.println(start);String sj = request.getParameter("sj");System.out.println(sj);//SQL查詢ResultSet re;Connection con = DriverManager.getConnection(url);Statement statement = con.createStatement();int id = Integer.valueOf(request.getParameter("id"));String sql = "select * from " + tableName + " where id=" + id;System.out.println(sql);re = statement.executeQuery(sql); while(re.next()) {%><form action="UpdateServlet" method="get"><table border="0" width="30%"><tr align="left"><td>車次</td><td><input type="text" name="upcc" value="<% out.print(re.getString(2)); %>"></td></tr><tr align="left"><td>起始點(diǎn)</td><td><input type="text" name="upstart" value="<% out.print(re.getString(3)); %>"></td></tr><tr align="left"><td>目的地</td><td><input type="text" name="upend" value="<% out.print(re.getString(4)); %>"></td></tr><tr align="left"><td>時(shí)間</td><td><input type="text" name="uptime" value="<% out.print(re.getString(5)); %>"></td></tr><tr align="left"><td>價(jià)格</td><td><input type="text" name="upprice" value="<% out.print(re.getString(6)); %>"></td></tr><tr align="left"><td>備注</td><td><input type="text" name="upother" value="<% out.print(re.getString(7)); %>"></td></tr><tr align="left"><td colspan="2"><input type="hidden" name="id" value="<% out.print(re.getString(1)); %>"></td></tr><tr align="center"><td><input type="submit" name="upsub" value="提交"></td><td><input type="reset" name="upreset" value="撤銷"></td></tr><%}%></table></form> <hr width="90%" color="red" size="3" />?2019 YXZ 使用訂票系統(tǒng)前必讀意見(jiàn)反饋京ICP證030173號(hào) <br />貴州財(cái)經(jīng)大學(xué)信息學(xué)院YXZ所有京公網(wǎng)安備11000002000001號(hào) </div></body> </html>

注意：隱藏了一個(gè)input控件作為id值獲取，UpdateServlet中SQL語(yǔ)句需要通過(guò)它更新數(shù)據(jù)。

2.此時(shí)運(yùn)行結(jié)果如下圖所示，其內(nèi)容是可以替換的。

比如修改信息如下所示，包括時(shí)間、票價(jià)、備注，點(diǎn)擊“提交”按鈕。

其運(yùn)行結(jié)果如下所示，這是因?yàn)镾ervlet還沒(méi)有創(chuàng)建。

3.創(chuàng)建UpdateServlet類，并添加相關(guān)代碼，需要注意訪問(wèn)路徑設(shè)置如下。

package servlet;import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement;import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;public class UpdateServlet extends HttpServlet {public UpdateServlet() {super();}public void destroy() {super.destroy(); // Just puts "destroy" string in log// Put your code here}public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//設(shè)置編碼方式request.setCharacterEncoding("UTF-8");response.setCharacterEncoding("UTF-8");//驅(qū)動(dòng)的名稱String driverName = "com.mysql.jdbc.Driver";//數(shù)據(jù)庫(kù)用戶名密碼String userName = "root";String userPwd = "123456";//數(shù)據(jù)庫(kù)名字String dbName = "hcp";//表名String tableName = "info";//拼接字符串鏈接數(shù)據(jù)庫(kù)String url = "jdbc:mysql://localhost:3306/" + dbName + "?user="+ userName + "&password=" +userPwd +"&useUnicode=true&characterEncoding=UTF-8";//鏈接數(shù)據(jù)庫(kù)try {Class.forName("com.mysql.jdbc.Driver").newInstance();//獲取URL傳遞參數(shù) 中文亂碼??????????轉(zhuǎn)換int id = Integer.valueOf(request.getParameter("id"));String upcc = new String(request.getParameter("upcc").getBytes("ISO-8859-1"), "UTF-8"); //車次String upstart = new String(request.getParameter("upstart").getBytes("ISO-8859-1"), "UTF-8"); //起始點(diǎn)String upend = new String(request.getParameter("upend").getBytes("ISO-8859-1"), "UTF-8"); //目的地String uptime = new String(request.getParameter("uptime").getBytes("ISO-8859-1"), "UTF-8"); //時(shí)間String upprice = new String(request.getParameter("upprice").getBytes("ISO-8859-1"), "UTF-8"); //價(jià)格String upother = new String(request.getParameter("upother").getBytes("ISO-8859-1"), "UTF-8"); //備注System.out.println(upother);//SQL查詢Connection con = DriverManager.getConnection(url);Statement statement = con.createStatement();String sql = "update " + tableName + " set start='" + upstart + "' , end='" + upend + "' , name='" + upcc + "' , starttime='" + uptime + "' , price='" + upprice+ "' , other='" + upother + "' where id=" + id + ";";System.out.println(sql);//執(zhí)行SQL語(yǔ)句statement.execute(sql);//關(guān)閉連接 statement.close(); con.close();} catch (InstantiationException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalAccessException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}//重定向到//response.sendRedirect("index.jsp");PrintWriter out = response.getWriter();out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");out.println("<HTML>");out.println(" <HEAD><TITLE>A Servlet</TITLE>");out.println("<meta http-equiv='Content-Type' content='text/html; charset=utf-8' />");out.println("<HEAD>");out.println(" <BODY>");out.println ("<script language=javascript>alert('更新成功!!!');window.location='index.jsp'</script>");out.println(" </BODY>");out.println("</HTML>");out.flush();out.close(); }public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html");PrintWriter out = response.getWriter();out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");out.println("<HTML>");out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");out.println(" <BODY>");out.print(" This is ");out.print(this.getClass());out.println(", using the POST method");out.println(" </BODY>");out.println("</HTML>");out.flush();out.close();}public void init() throws ServletException {// Put your code here} }

此時(shí)的文件結(jié)果如下圖所示：

update info set start=‘武漢’ , end=‘T34’ , name=‘貴陽(yáng)’ , starttime=‘2019-07-06 12:00:00.0’ ,
price=‘188’ , other=‘這是一張很棒的火車票。’ where id=4;
輸出結(jié)果如下圖所示：

注意：GET方法可能存在中文編碼錯(cuò)誤，輸出“???”，修改方法主要是request調(diào)用setCharacterEncoding(“UTF-8”)方法設(shè)置為UTF-8。同時(shí)，下面獲取的值也轉(zhuǎn)碼成UTF-8。

五.總結(jié)

目前雖然實(shí)現(xiàn)了網(wǎng)站的功能，但其代碼非常雜亂，JSP中嵌套這JAVA，JAVA中又嵌套著HTML，而我想實(shí)現(xiàn)的功能是：JSP就賦值布局，顯示界面；Java就負(fù)責(zé)連接數(shù)據(jù)庫(kù)、數(shù)據(jù)庫(kù)增刪改查，處理結(jié)果再返回給JSP中顯示，而不是相互嵌套的。換句話說(shuō)：JSP中點(diǎn)擊“提交”按鈕，TextBox中傳遞出發(fā)地，Java中接著請(qǐng)求，數(shù)據(jù)庫(kù)查詢，得到的結(jié)果再返回給JSP中顯示。

那怎么實(shí)現(xiàn)呢？
接下來(lái)我們將介紹DAO和Java Bean對(duì)JDBC進(jìn)行分層、模塊化的最有效兩個(gè)方法。DAO(數(shù)據(jù)庫(kù)操作對(duì)象，Database Access Object)是JDBC下常用模式，DAO出現(xiàn)之前，操作數(shù)據(jù)庫(kù)的代碼與業(yè)務(wù)代碼都出現(xiàn)在Servlet或者JSP中，不利用業(yè)務(wù)代碼的分離。DAO出現(xiàn)后，所有與數(shù)據(jù)庫(kù)相關(guān)的操作全被拿到了DAO層實(shí)現(xiàn)，Servlet或JSP只操作Java Bean或者DAP層，而DAO層值操作數(shù)據(jù)庫(kù)。

周末的深夜，呆在辦公室準(zhǔn)備明天的JAVA網(wǎng)站開(kāi)發(fā)實(shí)訓(xùn)，不同的是，這次有學(xué)生陪伴。各行各業(yè)都很辛苦，996和5+2讓我們更珍惜生活，學(xué)生也更應(yīng)該抓住編程的時(shí)光。看到學(xué)生開(kāi)始學(xué)會(huì)分享博客、分享知識(shí)，真的很高興，又拉了一些人“入坑”，傳道授業(yè)解惑，為之而努力。
夜色已深，月光打在身上，勾勒出你看書(shū)時(shí)最美的側(cè)臉，吹滅讀書(shū)燈，一身都是月，任是尋常動(dòng)人，想你了。接著在辦公室寫代碼了，fighting

（By:Eastmount 2019-07-06 夜9點(diǎn) http://blog.csdn.net/eastmount/）

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