本日学习了Java web的内容，对周一测试的系统进行了完善，添加了删除的操作，在运行测试时遇到了删除文章时会删除所有标题相同文章，在经过思考后决定对所有文章进行编号操作，在删除搜索时通过标题搜索文章，删除时则根据文章的编号进行删除，将编号设置为自增的键值，在用户创建文章时自动为文章赋予编号，可保证编号的唯一性。
Test.java新增代码:
1 public void deletedata(String biao) { 2 Connection connection = getConnection(); 3 PreparedStatement preparedStatement = null; 4 try { 5 String sql = "delete from bao where 标题 = ?"; 6 preparedStatement = connection.prepareStatement(sql); 7 preparedStatement.setString(1, biao); 8 preparedStatement.executeUpdate(); 9 //System.out.println("删除成功"); 10 11 } catch (SQLException e) { 12 e.printStackTrace(); 13 } finally { 14 close(preparedStatement); 15 close(connection); 16 } 17 } 18 19 public boolean isSame(String s) { 20 Connection connection = getConnection(); 21 PreparedStatement preparedStatement = null; 22 ResultSet rs = null; 23 try { 24 String sql = "select * from bao"; 25 preparedStatement = connection.prepareStatement(sql); 26 rs = preparedStatement.executeQuery(); 27 while (rs.next()) { 28 if (s.equals(rs.getObject(1))) 29 return true; 30 } 31 //preparedStatement.executeUpdate(); 32 33 } catch (SQLException e) { 34 e.printStackTrace(); 35 } finally { 36 close(rs); 37 close(preparedStatement); 38 close(connection); 39 } 40 return false; 41 }
删除页面和操作代码:
delete.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html> 4 <html> 5 <head> 6 <meta charset="UTF-8"> 7 <title>删除</title> 8 </head> 9 <body> 10 <form action="deletejudge.jsp" method="get"> 11 <p style="text-align:center;color: black; font-family: 宋体; font-size: 20px"> 12 <br> 要删除的日记标题: <input type="text" name="biao" /> <br> 13 <br><input type="submit" value="确定" /> 14 <br> <input type="button" value="返回菜单" onclick="location.href='index.jsp'" /> <br> 15 </p> 16 </form> 17 </body> 18 </html>
deletejudge.jsp
1 <%@ page language="java" import="java.sql.*" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html> 4 <html> 5 <head> 6 <meta charset="UTF-8"> 7 </head> 8 <body> 9 10 <jsp:useBean id="util" class="test.Test" scope="page" /> 11 <% 12 String biao=(String)request.getParameter("biao"); 13 if(biao==""){ 14 out.print("<script language='javaScript'> alert('输入为空'); window.history.back(-1); </script>"); 15 } 16 else if(!util.isSame(biao)) 17 { 18 out.print("<script language='javaScript'> alert('该信息不存在'); window.history.back(-1); </script>"); 19 } 20 else{ 21 %> 22 <table border="1"style="text-align:center;"> 23 <tr> 24 <td align="center" width=6%>标题</td> 25 <td align="center" width=8%>正文</td> 26 <td align="center" width=10%>天数</td> 27 <td align="center" width=3%>删除</td> 28 </tr> 29 <% 30 Connection connection = util.getConnection(); 31 PreparedStatement preparedStatement=null; 32 ResultSet rs=null; 33 try { 34 String sql = "select * from bao"; 35 preparedStatement=connection.prepareStatement(sql); 36 rs=preparedStatement.executeQuery(); 37 while(rs.next()){ 38 if(biao.equals(rs.getObject(1))) 39 { 40 %> 41 <tr> 42 <td align="center"><%=rs.getObject(1) %></td> 43 <td align="center"><%=rs.getObject(2) %></td> 44 <td align="center"><%=rs.getObject(3) %></td> 45 <td align="center"><a style="color:blue" href='deletejudge1.jsp?biao=<%=rs.getObject(1) %>' onclick="javascript:return del()">删除</a> </td> 46 </tr> 47 48 <% 49 } 50 } 51 } catch (SQLException e) { 52 e.printStackTrace(); 53 }finally{ 54 util.close(rs); 55 util.close(preparedStatement); 56 util.close(connection); 57 } 58 %> 59 </table> 60 <% 61 } 62 %> 63 <%-- 64 界面提示 65 --%> 66 <script> 67 function del(){ 68 var r = confirm("确定要删除吗？") 69 if (r == true) { 70 return true; 71 } else { 72 return false; 73 } 74 } 75 </script> 76 <p style="text-align:center;color: black; font-family: 宋体; font-size: 20px"> 77 <br> <input type="button" value="返回菜单" onclick="location.href='index.jsp'" /> <br> 78 </p> 79 </body> 80 </html>
deletejudge1.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html> 4 <html> 5 <head> 6 <meta charset="UTF-8"> 7 </head> 8 <body> 9 <input type="button" onclick="" value="删除"/> 10 <jsp:useBean id="util" class="test.Test" scope="page" /> 11 <% 12 String biao=(String)request.getParameter("biao"); 13 util.deletedata(biao); 14 out.print("<script language='javaScript'> alert('删除成功');</script>"); 15 response.setHeader("refresh", "0;url=delete.jsp"); 16 %> 17 <p style="text-align:center;color: black; font-family: 宋体; font-size: 20px"> 18 <br> <input type="button" value="返回菜单" onclick="location.href='index.jsp'" /> <br> 19 </p> 20 </body> 21 </html>
