项目中修改的操作

修改套路：（有两步：先获取id，在执行修改）

1. 在修改按钮添加：

href="${ pageContext.request.contextPath }/CategoryServlet?method=getId&cid=${category.cid }"

2. 在控制器获取id

//获取id

public void getId(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//获取list.jsp传过来的cid

String cid=request.getParameter("cid");

Category category=cs.selectById(cid);

request.setAttribute("category", category);

request.getRequestDispatcher("admin/category/edit.jsp").forward(request, response);

}

3. 此时进入修改页面：修改此页面的form返回的路径

action="${pageContext.request.contextPath}/CategoryServlet?method=update&cid=${category.cid }"

并用value获取此页面的用户名和id(隐藏域)  value="${category.cname }"

4. 控制器中获取修改页面传过来的数据

public void update(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

String cid=request.getParameter("cid");

String cname=request.getParameter("cname");

Category c=new Category();

c.setCid(cid);

c.setCname(cname);

int count=cs.update(c);

if(count>0){

//成功

request.getRequestDispatcher("CategoryServlet?method=selectAll").forward(request, response);

}else{

//失败

request.getRequestDispatcher("CategoryServlet?method=selectAll").forward(request, response);

}