這種方式能修改成功

<td align="right" >?

<a href="javascript:document.getElementById('updateForm').submit();">保存</a> &nbsp;&nbsp;

<a href="javascript:window.history.back();">退回 </a>

</td>

</tr>

</table>

<br/>

?<br>

?<form id="updateForm" method="post" action="<%=request.getContextPath() %>/department/department_update?did=${update_department.did}" >

<%-- <input type="hidden" name="did" value="${update_department.did} "> --%>

<table style="font-size::16px">

<tr>

? <td>部門(mén)名稱：</td>

? <td><input type="text" name="dname" value="${update_department.dname} "/></td>

</tr>

<tr>

? <td>部門(mén)介紹：</td>

? <td></td>

</tr>

<tr>

? <td width="10%"></td>

? <td>

? ? ?<textarea cols="50" rows="5" name="ddesc">${update_department.ddesc}</textarea>

? </td>

</tr>

</table>

這種范是修改失敗，setId失敗（setId不能使用String參數(shù)）

<a href="javascript:document.getElementById('updateForm').submit();">保存</a> &nbsp;&nbsp;

<a href="javascript:window.history.back();">退回 </a>

</td>

</tr>

</table>

<br/>

?<br>

?<form id="updateForm" method="post" action="<%=request.getContextPath() %>/department/department_update" >

<input type="hidden" name="did" value="${update_department.did} ">

<table style="font-size::16px">

<tr>

? <td>部門(mén)名稱：</td>

? <td><input type="text" name="dname" value="${update_department.dname} "/></td>

</tr>

<tr>

? <td>部門(mén)介紹：</td>

? <td></td>

</tr>

<tr>

? <td width="10%"></td>

? <td>

? ? ?<textarea cols="50" rows="5" name="ddesc">${update_department.ddesc}</textarea>

? </td>

對(duì)應(yīng)action如下

public String update(){

System.out.println(department.getDid());

System.out.println(department.getDname());

System.out.println(department.getDdesc());

//return NONE;

departmentService.update(department);

return "update_success";

}

這是什么原因？？？