不能刪除記錄

<%@page import="java.util.logging.Logger"%> 
<%@page import="java.util.logging.Level"%> 
<%@page language="java" import="java.util.*"%> 
<%@page language="java" import="java.sql.*"%> 
<%@page contentType="text/html" pageEncoding="UTF-8"%> 
<% 
    //String id4 = request.getParameter("id3"); 
    //int id5=Integer.ParseInt("id4"); 
    String id4 = request.getParameter("id3"); 

    if (id4 != null) { 
     // int id4 = Integer.parseInt(request.getParameter("id3.trim()")); 
     Connection con = null; 
     int id5 = Integer.parseInt("id4"); 

     try { 
      Class.forName("com.mysql.jdbc.Driver"); 
      con = DriverManager.getConnection("jdbc:mysql://localhost/login?  user=root&password=root"); 
      Statement stmt = con.createStatement(); 
      String sql = "delete from login2 where id=" + id5; 
      int i = stmt.executeUpdate(sql); 
      if (i > 0) { 
       response.sendRedirect("index.jsp"); 
      } 
      out.println("failed"); 
      con.close(); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
    } 
%>

我不能刪除record..the ID4正在空value.how修復它..不能刪除記錄

String id = request.getParameter("id"); 
int id1 = Integer.parseInt(id); 
final String email = request.getParameter("email"); 
final String password = request.getParameter("pass"); 
Connection con = null; 

try { 
    Class.forName("com.mysql.jdbc.Driver"); 

    con = DriverManager.getConnection("jdbc:mysql://localhost/login? user=root&password=root"); 

    Statement stmt = con.createStatement(); 
    HttpSession session = request.getSession(); 
    String idd = (String) session.getAttribute("id1"); 
    String sql = "INSERT INTO login2(email,pass)" + " VALUES('" + email + "','" + password + "')"; 
    stmt.execute(sql); 
    PrintWriter out = response.getWriter(); 

    out.println("successfully registered"); 
    ResultSet rs = stmt.executeQuery("select * from login2"); 
    response.setContentType("text/html"); 
    out.println("<html><body>"); 
    out.println("<table border=1 width=50% height=50%>"); 
    out.println("<tr><th>id</th><th>email</th><th>pasword</th> <th>action</th><tr>"); 

    while (rs.next()) { 
     int id2 = rs.getInt("id"); 
     String id9 = request.getParameter("id"); 
     int id0 = Integer.parseInt(id9); 
     String email1 = rs.getString("email"); 
     String pass1 = rs.getString("pass"); 
     //int s = rs.getInt("sal"); 
     out.println("<tr> <td>" + id2 + "</td> <td>" + email1 + "</td><td>" + pass1 + "</td> </tr>"); 
     out.println("<tr><td><a href= delete.jsp? id3=<%=rs.getInt(\"id\")% >delete</a></td></tr>"); 
     //out.println("<tr><td><a HREF=\"delete.jsp\">link</a></td></tr>"); 
    } 

    out.println("</table>"); 
    out.println("</html></body>"); 
}

這是我顯示記錄的servlet頁面。

來源

2016-03-06 nimmy

out.println("<tr><td><a href= \"delete.jsp?id3=\""+ rs.getInt("id") +"\">delete</a></td></tr>");

請提供[MCVE（HTTP ：//stackoverflow.com/help/mcve） –

你刪除記錄的JSP必須扔NumberFormatException因爲你正在努力無效的字符串編號

int id5 = Integer.parseInt("id4");除去周圍ID4 "才ID4字符串將被轉換成int轉換。

如果你是在表達得到的id4null值String id4 = request.getParameter("id3");

更新：

試試這個：代替out.println("<tr><td><a href= delete.jsp? id3=<%=rs.getInt(\"id\")% >delete</a></td></tr>");

來源

2016-03-06 17:08:44 Mahendra

不，它仍然不起作用。:( – nimmy

你能否用更新後的代碼更新你的問題？ – Mahendra

out.println（「delete」）; – nimmy

不能刪除記錄

回答

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