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练习JavaWeb连接数据库

时间：2021-07-01 10:21:17 帮助过：11人阅读

="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <form action="Check.jsp" method="post"> 卡号：<input type="text" name="cardid"><br> 密码：<input type="password" name="password"><br> 按钮：<input type="submit" value="登录"> </form> </body> </html>

3.创建接收页面

  1. <%@page <span style="color: #0000ff">import</span>="java.sql.ResultSet"%>
  2. <%@page <span style="color: #0000ff">import</span>="java.sql.PreparedStatement"%>
  3. <%@page <span style="color: #0000ff">import</span>="java.sql.Connection"%>
  4. <%@page <span style="color: #0000ff">import</span>="java.sql.DriverManager"%>
  5. <%@ page language="java" contentType="text/html; charset=UTF-8"<span style="color: #000000">
  6.     pageEncoding</span>="UTF-8"%>
  7. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
  8. <html>
  9. <head>
  10. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  11. <title>Insert title here</title>
  12. </head>
  13. <body>
  14. <%
  15. <span style="color: #008000">//</span><span style="color: #008000">接收验证</span>
  16.     String cardid = request.getParameter("cardid"<span style="color: #000000">);
  17.     String password </span>= request.getParameter("password"<span style="color: #000000">);
  18.     </span><span style="color: #008000">//</span><span style="color: #008000">数据验证</span>
  19.     <span style="color: #0000ff">if</span>(cardid.equals("")||password.equals(""<span style="color: #000000">))
  20.     {
  21.         out.write(</span>"请正确登录系统"<span style="color: #000000">);
  22.     }
  23.     </span><span style="color: #0000ff">else</span> <span style="color: #0000ff">if</span>(cardid==<span style="color: #0000ff">null</span>||password==<span style="color: #0000ff">null</span><span style="color: #000000">)
  24.     {
  25.         out.write(</span>"请正确登录系统"<span style="color: #000000">);
  26.     }
  27.     </span><span style="color: #0000ff">else</span><span style="color: #000000">
  28.     {
  29.         out.write(cardid);
  30.         out.write(password);
  31.     
  32.     </span><span style="color: #008000">//</span><span style="color: #008000">连接数据库</span>
  33.     Class.forName("oracle.jdbc.driver.OracleDriver"<span style="color: #000000">);
  34.     Connection conn </span>=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "test0816", "laoer123"<span style="color: #000000">);
  35.     PreparedStatement ps </span>= conn.prepareStatement("select * from t_balance where card_id=? and password=?  "<span style="color: #000000">);
  36.     ps.setString(</span>1<span style="color: #000000">, cardid);
  37.     ps.setString(</span>2<span style="color: #000000">,password);
  38.     ResultSet rs </span>=<span style="color: #000000">ps.executeQuery();
  39. </span><span style="color: #008000">//</span><span style="color: #008000">数据验证</span>
  40.     <span style="color: #0000ff">if</span><span style="color: #000000">(rs.next())
  41.     {
  42.         out.write(</span>"用户名和密码正确"<span style="color: #000000">);
  43.     }
  44.     </span><span style="color: #0000ff">else</span><span style="color: #000000">
  45.     {
  46.         out.write(</span>"用户名或密码错误"<span style="color: #000000">);
  47.     }
  48.     rs.close();
  49.     ps.close();
  50.     conn.close();
  51. }
  52.    
  53. </span>%>
  54. </body>
  55. </html>

4.通过连接池连接数据库

 （1）添加jar包，同上。

 （2）在JavaResources - src- 创建java包 -创建类 ，并将配置文件放在src下

    

  1. <span style="color: #0000ff">package</span><span style="color: #000000"> com.hanqi.web;
  2. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.Connection;
  3. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.PreparedStatement;
  4. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.ResultSet;
  5. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.SQLException;
  6. </span><span style="color: #0000ff">import</span><span style="color: #000000"> com.mchange.v2.c3p0.ComboPooledDataSource;
  7. </span><span style="color: #008000">//</span><span style="color: #008000">单例模式</span>
  8. <span style="color: #0000ff">public</span> <span style="color: #0000ff">class</span><span style="color: #000000"> CardDAO {
  9.     </span><span style="color: #008000">//</span><span style="color: #008000">构建连接池对象并配置</span>
  10.     <span style="color: #0000ff">private</span>  ComboPooledDataSource cpds =<span style="color: #0000ff">new</span> ComboPooledDataSource("helloc3p0"<span style="color: #000000">);
  11.     
  12.     </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">boolean</span><span style="color: #000000"> checklogin(String cardid,String password)
  13.     {
  14.         </span><span style="color: #0000ff">boolean</span> rtn =<span style="color: #0000ff">false</span><span style="color: #000000">;
  15.         </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
  16.                 Connection conn </span>=<span style="color: #000000"> cpds.getConnection();
  17.                 PreparedStatement ps </span>= conn.prepareStatement("select * from t_balance where card_id=? and password=?  "<span style="color: #000000">);
  18.                 ps.setString(</span>1<span style="color: #000000">, cardid);
  19.                 ps.setString(</span>2<span style="color: #000000">,password);
  20.                 ResultSet rs </span>=<span style="color: #000000">ps.executeQuery();
  21.                 
  22.                 rtn</span>=<span style="color: #000000">rs.next();
  23.                 rs.close();
  24.                 ps.close();
  25.                 
  26.                 conn.close();
  27.             } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (SQLException e) {
  28.             </span><span style="color: #008000">//</span><span style="color: #008000"> TODO Auto-generated catch block</span>
  29. <span style="color: #000000">            e.printStackTrace();
  30.         }
  31.         </span><span style="color: #0000ff">return</span><span style="color: #000000"> rtn;
  32.     }
  33.     
  34.     
  35. }
  36.     </span>

请求信息页面

  1. <span style="background-color: #ffff00; color: #000000"><%</span><span style="background-color: #f5f5f5; color: #000000">@ page language</span><span style="background-color: #f5f5f5; color: #000000">=</span><span style="background-color: #f5f5f5; color: #800000">"</span><span style="background-color: #f5f5f5; color: #800000">java</span><span style="background-color: #f5f5f5; color: #800000">"</span><span style="background-color: #f5f5f5; color: #000000"> contentType</span><span style="background-color: #f5f5f5; color: #000000">=</span><span style="background-color: #f5f5f5; color: #800000">"</span><span style="background-color: #f5f5f5; color: #800000">text/html; charset=UTF-8</span><span style="background-color: #f5f5f5; color: #800000">"</span><span style="background-color: #f5f5f5; color: #000000">
  2.     pageEncoding</span><span style="background-color: #f5f5f5; color: #000000">=</span><span style="background-color: #f5f5f5; color: #800000">"</span><span style="background-color: #f5f5f5; color: #800000">UTF-8</span><span style="background-color: #f5f5f5; color: #800000">"</span><span style="background-color: #ffff00; color: #000000">%></span>
  3. <span style="color: #0000ff"><!</span><span style="color: #ff00ff">DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"</span><span style="color: #0000ff">></span>
  4. <span style="color: #0000ff"><</span><span style="color: #800000">html</span><span style="color: #0000ff">></span>
  5. <span style="color: #0000ff"><</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
  6. <span style="color: #0000ff"><</span><span style="color: #800000">meta </span><span style="color: #ff0000">http-equiv</span><span style="color: #0000ff">="Content-Type"</span><span style="color: #ff0000"> content</span><span style="color: #0000ff">="text/html; charset=UTF-8"</span><span style="color: #0000ff">></span>
  7. <span style="color: #0000ff"><</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>Insert title here<span style="color: #0000ff"></</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>
  8. <span style="color: #0000ff"></</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
  9. <span style="color: #0000ff"><</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
  10. <span style="color: #0000ff"><</span><span style="color: #800000">form </span><span style="color: #ff0000">action</span><span style="color: #0000ff">="Check2.jsp"</span><span style="color: #ff0000"> method</span><span style="color: #0000ff">="post"</span><span style="color: #0000ff">></span><span style="color: #000000">
  11. 卡号：</span><span style="color: #0000ff"><</span><span style="color: #800000">input </span><span style="color: #ff0000">type</span><span style="color: #0000ff">="text"</span><span style="color: #ff0000"> name</span><span style="color: #0000ff">="cardid"</span><span style="color: #0000ff">><</span><span style="color: #800000">br</span><span style="color: #0000ff">></span><span style="color: #000000">
  12. 密码：</span><span style="color: #0000ff"><</span><span style="color: #800000">input </span><span style="color: #ff0000">type</span><span style="color: #0000ff">="password"</span><span style="color: #ff0000"> name</span><span style="color: #0000ff">="password"</span><span style="color: #0000ff">><</span><span style="color: #800000">br</span><span style="color: #0000ff">></span><span style="color: #000000">
  13. 按钮：</span><span style="color: #0000ff"><</span><span style="color: #800000">input </span><span style="color: #ff0000">type</span><span style="color: #0000ff">="submit"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="登录"</span><span style="color: #0000ff">></span>
  14. <span style="color: #0000ff"></</span><span style="color: #800000">form</span><span style="color: #0000ff">></span>
  15. <span style="color: #0000ff"></</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
  16. <span style="color: #0000ff"></</span><span style="color: #800000">html</span><span style="color: #0000ff">></span>

接收信息的页面

  1. <%@page <span style="color: #0000ff">import</span>="com.hanqi.web.CardDAO"%>
  2. <%@ page language="java" contentType="text/html; charset=UTF-8"<span style="color: #000000">
  3.     pageEncoding</span>="UTF-8"%>
  4. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
  5. <html>
  6. <head>
  7. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  8. <title>Insert title here</title>
  9. </head>
  10. <body>
  11. <% 
  12.     <span style="color: #008000">//</span><span style="color: #008000">    设置不缓存页面</span>
  13.     response.setHeader("Cache-Control", "no-cache"<span style="color: #000000">);
  14.     </span><span style="color: #008000">//</span><span style="color: #008000">定时跳转
  15.     </span><span style="color: #008000">//</span><span style="color: #008000">response.setHeader("refresh", "2;URL=</span><span style="color: #008000; text-decoration: underline">http://www.baidu.com</span><span style="color: #008000">");
  16.     </span><span style="color: #008000">//
  17. </span><span style="color: #000000">
  18. String cardid </span>= request.getParameter("cardid"<span style="color: #000000">);
  19. String password </span>=request.getParameter("password"<span style="color: #000000">);
  20. </span><span style="color: #0000ff">if</span>(cardid==<span style="color: #0000ff">null</span>||password==<span style="color: #0000ff">null</span>||<span style="color: #000000">
  21. cardid.equals(</span>"")||password.equals(""<span style="color: #000000">))
  22. {
  23.     out.write(</span>"请正确登录"<span style="color: #000000">);
  24. }
  25. </span><span style="color: #0000ff">else</span><span style="color: #000000">
  26. {
  27.     </span><span style="color: #008000">//</span><span style="color: #008000">检查登录信息</span>
  28.     CardDAO cd = <span style="color: #0000ff">new</span><span style="color: #000000"> CardDAO();
  29.     </span><span style="color: #0000ff">if</span><span style="color: #000000">(cd.checklogin(cardid, password))
  30.     {
  31.         </span><span style="color: #008000">//</span><span style="color: #008000">out.write("登录成功！");</span>
  32. <span style="color: #000000">        
  33.         response.getWriter().write(</span>"验证成功！"<span style="color: #000000">);
  34.         </span><span style="color: #008000">//</span><span style="color: #008000">页面跳转
  35.         </span><span style="color: #008000">//</span><span style="color: #008000">response.sendRedirect("Main.jsp");</span>
  36.         response.sendRedirect("http://www.baidu.com"<span style="color: #000000">);
  37.     }
  38.     </span><span style="color: #0000ff">else</span><span style="color: #000000">
  39.     {
  40.         out.write(</span>"登录失败！"<span style="color: #000000">);
  41.         </span><span style="color: #008000">//</span><span style="color: #008000">跳回登录页面</span>
  42.         response.setHeader("refresh", "2;URL=loginin.jsp"<span style="color: #000000">);
  43.     }
  44. }
  45. </span>%>
  46. </body>
  47. </html>

附原本的图，不是以上程序

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练习JavaWeb连接数据库

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