5.修改数据

5.1编写查询条件页面

修改单条数据的时候，首先是查询出单个数据的详细信息，然后根据实际需要部分修改或者全部修改。修改之后，数据会提交到数据库，数据库中保存更新以后的数据。

查询出单条数据的查询条件页面代码如下：

QueryToUpdate.html

  1. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
  2. <html>
  3.   <head>
  4.     <title>QueryToUpdate.html</title>
  5.  
  6.     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
  7.     <meta http-equiv="description" content="this is my page">
  8.     <meta http-equiv="content-type" content="text/html; charset=UTF-8">
  9.  
  10.     <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->
  11.  
  12.   </head>
  13.  
  14.   <body>
  15.     <form name="f1" id="f1" action="/jdbc_servlet/servlet/QueryToUpdateServlet" method="post">
  16.       <table border="0">
  17.         <tr>
  18.           <td>请输入要修改的部门编号:</td><tr></tr>
  19.           <td><input type="text" name="id" ></td>
  20.         </tr>
  21.         <tr>
  22.           <td colspan="2" align="left"><input type="submit" value="提交"></td>
  23.         </tr>
  24.       </table>
  25.     </form>
  26.   </body>
  27. </html>

5.2 编写显示部门详细信息的Servlet

输入要修改的部门编号以后，进入根据部门编号查询部门信息的Servlet，把部门详细信息显示到页面中，一些不可以修改的字段可以设置成只读，这样就不会把这些数据修改了，该Servlet的代码如下：

QueryToUpdateServlet.java

  1. package com.cn.update;
  2.  
  3. import java.io.IOException;
  4. import java.io.PrintWriter;
  5. import java.sql.Connection;
  6. import java.sql.DriverManager;
  7. import java.sql.PreparedStatement;
  8. import java.sql.ResultSet;
  9. import java.sql.SQLException;
  10.  
  11. import javax.servlet.ServletException;
  12. import javax.servlet.http.HttpServlet;
  13. import javax.servlet.http.HttpServletRequest;
  14. import javax.servlet.http.HttpServletResponse;
  15.  
  16. public class QueryToUpdateServlet extends HttpServlet {
  17.  
  18.     /**
  19.      * Destruction of the servlet. <br>
  20.      */
  21.     public void destroy() {
  22.         super.destroy(); // Just puts "destroy" string in log
  23.         // Put your code here
  24.     }
  25.  
  26.     /**
  27.      * The doGet method of the servlet. <br>
  28.      *
  29.      * This method is called when a form has its tag value method equals to get.
  30.      *
  31.      * @param request the request send by the client to the server
  32.      * @param response the response send by the server to the client
  33.      * @throws ServletException if an error occurred
  34.      * @throws IOException if an error occurred
  35.      */
  36.     public void doGet(HttpServletRequest request, HttpServletResponse response)
  37.             throws ServletException, IOException {
  38.  
  39.         response.setContentType("text/html;charset=gb2312");
  40.         request.setCharacterEncoding("gb2312");
  41.         PrintWriter out = response.getWriter();
  42.         String id = request.getParameter("id");
  43.         Connection con = null;
  44.         PreparedStatement pstmt = null;
  45.         ResultSet rs = null;
  46.         try {
  47.             Class.forName("com.mysql.jdbc.Driver");
  48.             System.out.println("创建驱动成功！");
  49.             con = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");
  50.             System.out.println("数据库连接成功！");
  51.             String sql = "SELECT * FROM dept WHERE id=?";
  52.             pstmt = con.prepareStatement(sql);
  53.             pstmt.setString(1, id);
  54.             rs = pstmt.executeQuery();
  55.         } catch (ClassNotFoundException e) {
  56.             // TODO Auto-generated catch block
  57.             e.printStackTrace();
  58.         } catch (SQLException e) {
  59.             // TODO Auto-generated catch block
  60.             e.printStackTrace();
  61.         }
  62.         //显示单个部门的信息
  63.         out.println("<html>"
  64.                 + "<head><title>显示单个部门信息</title></head>"
  65.                 + "<body>");
  66.         out.println("<h1>显示单个部门信息</h1><br><br>");
  67.         out.print("<form action='/jdbc_servlet/servlet/UpdateDeptServlet' method='post'>");
  68.         try {
  69.             while(rs.next()){
  70.                 out.println("部门编号：");
  71.                 out.print("<br>");
  72.                 //在文本框中显示部门编号，设置成只读
  73.                 out.println("<input type='text' name='id' readonly='true' value=");
  74.                 out.println(rs.getString(1).toString());
  75.                 out.print(">");
  76.                 out.print("<br>");
  77.                 out.println("部门名称：");
  78.                 out.print("<br>");
  79.                 //在文本框中显示部门名称
  80.                 out.println("<input type='text' name='d_name' value=");
  81.                 out.println(rs.getString(2).toString());
  82.                 out.print(">");
  83.                 out.print("<br>");
  84.                 out.println("部门地址：");
  85.                 out.print("<br>");
  86.                 //在文本框中显示部门地址
  87.                 out.println("<input type='text' name='address' value=");
  88.                 out.println(rs.getString(3).toString());
  89.                 out.print(">");
  90.                 out.print("<br>");
  91.                 out.println("部门人数：");
  92.                 out.print("<br>");
  93.                 //在文本框中显示部门人数
  94.                 out.println("<input type='text' name='empnumber' value=");
  95.                 out.println(rs.getString(4).toString());
  96.                 out.print(">");
  97.                 out.print("<br>");
  98.                 //提交按钮
  99.                 out.print("<input type='submit' value='Submit'>");
  100.                 out.print("</form>");
  101.  
  102.             }
  103.         } catch (SQLException e) {
  104.             // TODO Auto-generated catch block
  105.             e.printStackTrace();
  106.         }
  107.         out.flush();
  108.         out.close();
  109.     }
  110.  
  111.     /**
  112.      * The doPost method of the servlet. <br>
  113.      *
  114.      * This method is called when a form has its tag value method equals to post.
  115.      *
  116.      * @param request the request send by the client to the server
  117.      * @param response the response send by the server to the client
  118.      * @throws ServletException if an error occurred
  119.      * @throws IOException if an error occurred
  120.      */
  121.     public void doPost(HttpServletRequest request, HttpServletResponse response)
  122.             throws ServletException, IOException {
  123.  
  124.         response.setContentType("text/html;charset=gb2312");
  125.         request.setCharacterEncoding("gb2312");
  126.         PrintWriter out = response.getWriter();
  127.         this.doGet(request, response);
  128.         out.flush();
  129.         out.close();
  130.     }
  131.  
  132.     /**
  133.      * Initialization of the servlet. <br>
  134.      *
  135.      * @throws ServletException if an error occurs
  136.      */
  137.     public void init() throws ServletException {
  138.         // Put your code here
  139.     }
  140.  
  141. }

5.3编写处理修改操作的Servlet

在UpdateDeptServlet中，修改数据以后，显示出数据库表中的全部信息。UpdateDeptServlet的代码如下：

UpdateDeptServlet.java

  1. package com.cn.update;
  2.  
  3. import java.io.IOException;
  4. import java.io.PrintWriter;
  5. import java.sql.Connection;
  6. import java.sql.DriverManager;
  7. import java.sql.PreparedStatement;
  8. import java.sql.ResultSet;
  9. import java.sql.SQLException;
  10. import java.sql.Statement;
  11.  
  12. import javax.servlet.ServletException;
  13. import javax.servlet.http.HttpServlet;
  14. import javax.servlet.http.HttpServletRequest;
  15. import javax.servlet.http.HttpServletResponse;
  16.  
  17. public class UpdateDeptServlet extends HttpServlet {
  18.  
  19.     /**
  20.      * The doGet method of the servlet. <br>
  21.      *
  22.      * This method is called when a form has its tag value method equals to get.
  23.      *
  24.      * @param request the request send by the client to the server
  25.      * @param response the response send by the server to the client
  26.      * @throws ServletException if an error occurred
  27.      * @throws IOException if an error occurred
  28.      */
  29.     public void doGet(HttpServletRequest request, HttpServletResponse response)
  30.             throws ServletException, IOException {
  31.  
  32.         response.setContentType("text/html");
  33.         PrintWriter out = response.getWriter();
  34.         this.doPost(request, response);
  35.         out.flush();
  36.         out.close();
  37.     }
  38.  
  39.     /**
  40.      * The doPost method of the servlet. <br>
  41.      *
  42.      * This method is called when a form has its tag value method equals to post.
  43.      *
  44.      * @param request the request send by the client to the server
  45.      * @param response the response send by the server to the client
  46.      * @throws ServletException if an error occurred
  47.      * @throws IOException if an error occurred
  48.      */
  49.     public void doPost(HttpServletRequest request, HttpServletResponse response)
  50.             throws ServletException, IOException {
  51.  
  52.         response.setContentType("text/html;charset=gb2312");
  53.         request.setCharacterEncoding("gb2312");
  54.         PrintWriter out = response.getWriter();
  55.         Connection con = null;
  56.         PreparedStatement ps = null;
  57.         ResultSet rs = null;
  58.         Statement sta = null;
  59.         String id = request.getParameter("id");
  60.         String address = request.getParameter("address");
  61.         int empnumber = Integer.parseInt(request.getParameter("empnumber"));
  62.         String d_name = request.getParameter("d_name");
  63.         try {
  64.             Class.forName("com.mysql.jdbc.Driver");
  65.             System.out.println("创建驱动成功！");
  66.             con = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");
  67.             System.out.println("数据库连接成功！");
  68.             String sql = "UPDATE dept SET id=?,address=?,empnumber=?,d_name=? WHERE id=?";
  69.             ps = con.prepareStatement(sql);
  70.             //下面设置修改的数据值
  71.             ps.setString(1, id);
  72.             ps.setString(2, address);
  73.             ps.setInt(3, empnumber);
  74.             ps.setString(4, d_name);
  75.             ps.setString(5, id);
  76.             ps.executeUpdate();
  77.             System.out.println("修改成功！");
  78.             /*
  79.              * 添加成功后，显示全部信息
  80.              */
  81.             sta = con.createStatement();
  82.             rs = sta.executeQuery("SELECT * FROM dept");
  83.             //在页面中显示表中的所有信息
  84.             out.println(
  85.                     "<html>"+
  86.                     "<head><title>部门表信息</title></head>"+
  87.                     "<body>");
  88.             out.println("<h1>部门表信息:</h1><br><br>");
  89.             //循环遍历输出查询结果
  90.             while(rs.next()){
  91.                 out.print("部门编号：");
  92.                 out.print(rs.getString(1)+"\t");
  93.                 out.print("部门名称：");
  94.                 out.print(rs.getString(2)+"\t");
  95.                 out.print("部门地址：");
  96.                 out.print(rs.getString(3)+"\t");
  97.                 out.print("部门人数：");
  98.                 out.print(rs.getString(4)+"\t");
  99.                 out.println("<br>");
  100.             }
  101.             out.print("</body></html>");
  102.             out.close();
  103.         } catch (ClassNotFoundException e) {
  104.             // TODO Auto-generated catch block
  105.             e.printStackTrace();
  106.         } catch (SQLException e) {
  107.             // TODO Auto-generated catch block
  108.             e.printStackTrace();
  109.         }
  110.         out.flush();
  111.         out.close();
  112.     }
  113.  
  114.     /**
  115.      * Initialization of the servlet. <br>
  116.      *
  117.      * @throws ServletException if an error occurs
  118.      */
  119.     public void init() throws ServletException {
  120.         // Put your code here
  121.     }
  122.  
  123. }

6. 删除数据

删除数据时，要指定删除的条件，否则会把表中的所有数据删除。删除以后，被删除的数据在表中就不存在了。下面的例子是根据部门编号删除数据的例子。首先在页面中输入要删除的部门编号，输入要删除的部门编号的页面代码入下：

delete.html

  1. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
  2. <html>
  3.   <head>
  4.     <title>delete.html</title>
  5.  
  6.     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
  7.     <meta http-equiv="description" content="this is my page">
  8.     <meta http-equiv="content-type" content="text/html; charset=gb2312">
  9.  
  10.     <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->
  11.  
  12.   </head>
  13.  
  14.   <body>
  15.     <form name="f1" id="f1" action="/jdbc_servlet/servlet/DeleteByIdServlet" method="post">
  16.       <table border="0">
  17.         <tr>
  18.           <td>请输入要删除的部门编号:</td><tr></tr>
  19.           <td><input type="text" name="id" ></td>
  20.         </tr>
  21.         <tr>
  22.           <td colspan="2" align="left"><input type="submit" value="删除"></td>
  23.         </tr>
  24.       </table>
  25.     </form>
  26.   </body>
  27. </html>

当输入删除条件后，单击【删除】按钮，会进入form表单指定的DeleteByIdServlet中，这是一个servlet，用来处理删除操作。DeleteByIdServlet中的代码如下：

DeleteByIdServlet.java

  1. package com.cn.delete;
  2.  
  3. import java.io.IOException;
  4. import java.io.PrintWriter;
  5. import java.sql.Connection;
  6. import java.sql.DriverManager;
  7. import java.sql.PreparedStatement;
  8. import java.sql.ResultSet;
  9. import java.sql.SQLException;
  10.  
  11. import javax.servlet.ServletException;
  12. import javax.servlet.http.HttpServlet;
  13. import javax.servlet.http.HttpServletRequest;
  14. import javax.servlet.http.HttpServletResponse;
  15.  
  16. public class DeleteByIdServlet extends HttpServlet {
  17.  
  18.     /**
  19.      * The doGet method of the servlet. <br>
  20.      *
  21.      * This method is called when a form has its tag value method equals to get.
  22.      *
  23.      * @param request the request send by the client to the server
  24.      * @param response the response send by the server to the client
  25.      * @throws ServletException if an error occurred
  26.      * @throws IOException if an error occurred
  27.      */
  28.     public void doGet(HttpServletRequest request, HttpServletResponse response)
  29.             throws ServletException, IOException {
  30.  
  31.         response.setContentType("text/html");
  32.         PrintWriter out = response.getWriter();
  33.         this.doPost(request, response);
  34.         out.flush();
  35.         out.close();
  36.     }
  37.  
  38.     /**
  39.      * The doPost method of the servlet. <br>
  40.      *
  41.      * This method is called when a form has its tag value method equals to post.
  42.      *
  43.      * @param request the request send by the client to the server
  44.      * @param response the response send by the server to the client
  45.      * @throws ServletException if an error occurred
  46.      * @throws IOException if an error occurred
  47.      */
  48.     public void doPost(HttpServletRequest request, HttpServletResponse response)
  49.             throws ServletException, IOException {
  50.  
  51.         response.setContentType("text/html;charset=gb2312");
  52.         request.setCharacterEncoding("gb2312");
  53.         PrintWriter out = response.getWriter();
  54.         String id = request.getParameter("id");
  55.         Connection con = null;
  56. //        ResultSet rs = null;
  57.         PreparedStatement ps = null;
  58.         try {
  59.             Class.forName("com.mysql.jdbc.Driver");
  60.             System.out.println("创建驱动成功！");
  61.             con = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");
  62.             System.out.println("数据库连接成功！");
  63.             String sql = "DELETE FROM dept WHERE id=?";
  64.             ps = con.prepareStatement(sql);
  65.             ps.setString(1, id);
  66.             ps.executeUpdate();
  67.             System.out.println("删除成功！");
  68.             //显示结果信息
  69.             out.println("<html><head><title>"
  70.                     +"删除部门表数据</title></head>"+"<body>");
  71.             out.println("<h1>删除部门表数据成功！</h1>");
  72.             out.print("</body></html>");
  73.         } catch (ClassNotFoundException e) {
  74.             // TODO Auto-generated catch block
  75.             e.printStackTrace();
  76.         } catch (SQLException e) {
  77.             // TODO Auto-generated catch block
  78.             e.printStackTrace();
  79.         }
  80.         out.flush();
  81.         out.close();
  82.     }
  83.  
  84.     /**
  85.      * Initialization of the servlet. <br>
  86.      *
  87.      * @throws ServletException if an error occurs
  88.      */
  89.     public void init() throws ServletException {
  90.         // Put your code here
  91.     }
  92.  
  93. }

在DeleteByIdServlet中，获得页面传递过来的部门编号，然后根据部门编号删除该编号对应的数据，删除成功则在页面中提示删除成功。

html调用servlet（JDBC在Servlet中的使用）（2）的更多相关文章

  1. html调用servlet（JDBC在Servlet中的使用）（1）

    1.页面的数据表单 在使用Servlet处理用户请求之前,先准备一个页面,该页面用来提供数据表单.数据表单就是HTML中的<form>...</form>部分,当用户单击Sub ...

  2. Java Servlet(三)：Servlet中ServletConfig对象和ServletContext对象

    本文将记录ServletConfig/ServletContext中提供了哪些方法,及方法的用法. ServletConfig是一个抽象接口,它是由Servlet容器使用,在一个servlet对象初始 ...

  3. 登录小项目 js+servlet+jdbc+mvc

    项目名称: 沪上阿姨 实现需求: 实现用户登录 实现用户退出 实现用户注册 功能分析: 用户登录: 根据用户名和密码查询用户信息.查询则登录成功,查不到则登录失败. 用户退出: 销毁session 用 ...

  4. JDBC和servlet设计思路、DAO模式思路、MVC思路粗略总结

    #JDBC和Servlet联合起来使用的项目思路: 说明:建库,最好一开始设置utf8字符集 step1: 在数据库中建表 如   create table t_user{ ...... } step ...

  5. Jsp+Servlet+JDBC的使用复习

    最近对JDBC进行了复习,对事物的理解,连接池的使用等部分都有一个复习,所以使用Servlet+JDBC完成了一个小Demo,在这里对这种底层的操作进行总结.框架的使用的确方便了我们的开发,但是底层的 ...

  6. java web开发基础实例（javabean+jsp+servlet+jdbc）

    JavaBean:用于传递数据,拥有与数据相关的逻辑处理 JSP:从Model接收数据并生成HTML Servlet:接收HTTP请求并控制Model和View jdbc:用于配置环境 一.[建立数据 ...

  7. 使用JSP+Servlet+Jdbc+Echatrs实现对豆瓣电影Top250的展示

    使用JSP+Servlet+Jdbc+Echatrs实现对豆瓣电影Top250的展示 写在前面: 有的小伙伴,会吐槽啦,你这个标题有点长的啊.哈哈 ,好像是的!不过,这个也是本次案例中使用到的关键技术 ...

  8. 使用servlet+jdbc+MD5实现用户加密登录

    /** * 分析流程: * 1.前端页面提交登录请求 * 2.被web.xml拦截,进入到LoginServlet(有两种方式:方式一,在web.xml文件中配置servlet拦截器;方式二,不用在w ...

  9. Servlet从本地文件中读取图片，并显示在页面中

    import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpSer ...

  10. MVC-1(javabean+jsp+servlet+jdbc)

    这是一篇最初版本的mvc设计模式的demo.路要一步一步走,弄明白这其中的逻辑,对后面掌握ssh,ssm等框架大有裨益. 计算机系的同学们也要为毕设做准备了,希望可以帮你们迈出自己做毕设的第一步(微笑 ...

随机推荐

  1. LoadRunner FAQ2

    LR中参数的定义和赋值 1.参数的赋值和取值 lr_save_string("hello world","param"); lr_eval_string(&qu ...

  2. log4j:WARN No appenders could be found for logger (org.springframework.web.context.ContextLoader).

    一.异常描述: log4j:WARN No appenders could be found for logger (org.springframework.web.context.ContextLo ...

  3. hdoj1171 Big Event in HDU（01背包 || 多重背包）

    题目链接 http://acm.hdu.edu.cn/showproblem.php?pid=1171 题意 老师有一个属性:价值(value).在学院里的老师共有n种价值,每一种价值value对应着 ...

  4. [漏洞复现]CVE-2010-2883 Adobe Reader 打开pdf电脑即刻中招

    1.漏洞概述: CVE-2010-2883漏洞原理:“Adobe Reader在处理CoolType字体文件的sing表时,存在栈溢出漏洞,当打开特制的恶意PDF文件时,可允许任意代码远程执行.” 影 ...

  5. Block的基本用法

    NSString* (^myBlock)(NSString*, int); myBlock = ^(NSString *name, int age){ return [NSString stringW ...

  6. win 10 文件夹 背景 没效果

    韩梦飞沙 yue31313 韩亚飞 han_meng_fei_sha  313134555@qq.com

  7. Git 历险记

    Git历险记(一) 作为分布式版本控制系统的重要代表--Git已经为越来越多的人所认识,它相对于我们熟悉的CVS.SVN甚至同时分布式控制系统的Mercurial,有哪些优势和不足呢.这次InfoQ中 ...

  8. bzoj 3669 lct维护最小生成树

    大概题意:给一个无向图,有a,b两种边权,找一条从1到n的路径,使得max(a[i])+max(b[i])最小a[i],b[i]表示该路径上的边的对应权. 如果用类似最短路的DP来做,显然每个点的状态 ...

  9. Codeforces Round #354 (Div. 2) B. Pyramid of Glasses 模拟

    B. Pyramid of Glasses 题目连接: http://www.codeforces.com/contest/676/problem/B Description Mary has jus ...

  10. Codeforces Round #287 (Div. 2) A. Amr and Music 水题

    A. Amr and Music time limit per test 1 second memory limit per test 256 megabytes input standard inp ...