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>
标签：总结,preparedStatement,return,删除,rs,connection,第二周,close,星期四 From： https://www.cnblogs.com/sgle0722/p/17149279.html