首先是show.jspwhile(rs.next()) {
%> <table border="2">
<tr>
<td>StudentCode</td>
<td><%=rs.getInt("StudentCode") %></td>
</tr>
<tr>
<td>Name</td>
<td><%=rs.getString("Name") %></td>
</tr>
<tr>
<td>Grade</td>
<td><%=rs.getString("Grade") %></td>
</tr>
<tr>
<td>Class</td>
<td><%=rs.getString("Class") %></td>
</tr>
</table>
<a href = "replay.jsp">添加</a>
<a href = "Delete.jsp?StudentCode = <%= rs.getInt("StudentCode")%>">刪除</a>
跳转到Delete.jsp页面取值int StudentCodeId = Integer.parseInt(request.getParameter("StudentCode"));String sql ="delete from Student where StudentCode = " + StudentCodeId;
PreparedStatement stmt = conn.prepareStatement(sql);stmt.executeUpdate();conn.commit();stmt.close();
conn.close();编译运行 报错 java.lang.NumberFormatException: null
java.lang.Integer.parseInt(Integer.java:417)
java.lang.Integer.parseInt(Integer.java:499)
org.apache.jsp.Delete_jsp._jspService(Delete_jsp.java:58)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)具体为int StudentCode = Integer.parseInt(request.getParameter("StudentCode"));
错误 研究了 没想明白哪里错误 望高手指教
%> <table border="2">
<tr>
<td>StudentCode</td>
<td><%=rs.getInt("StudentCode") %></td>
</tr>
<tr>
<td>Name</td>
<td><%=rs.getString("Name") %></td>
</tr>
<tr>
<td>Grade</td>
<td><%=rs.getString("Grade") %></td>
</tr>
<tr>
<td>Class</td>
<td><%=rs.getString("Class") %></td>
</tr>
</table>
<a href = "replay.jsp">添加</a>
<a href = "Delete.jsp?StudentCode = <%= rs.getInt("StudentCode")%>">刪除</a>
跳转到Delete.jsp页面取值int StudentCodeId = Integer.parseInt(request.getParameter("StudentCode"));String sql ="delete from Student where StudentCode = " + StudentCodeId;
PreparedStatement stmt = conn.prepareStatement(sql);stmt.executeUpdate();conn.commit();stmt.close();
conn.close();编译运行 报错 java.lang.NumberFormatException: null
java.lang.Integer.parseInt(Integer.java:417)
java.lang.Integer.parseInt(Integer.java:499)
org.apache.jsp.Delete_jsp._jspService(Delete_jsp.java:58)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)具体为int StudentCode = Integer.parseInt(request.getParameter("StudentCode"));
错误 研究了 没想明白哪里错误 望高手指教
int StudentCodeId = Integer.parseInt(request.getParameter("StudentCode"));
request.getParameter("StudentCode")//先看看值是不是空
改为:StudentCode=<%= rs.getInt("StudentCode")%>
你把StudentCode = <%= rs.getInt("StudentCode")%>。
改为:StudentCode=<%= rs.getInt("StudentCode")%>
试试看。