java中getParameter()中的参数 (个人笔记)
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getParameter()函数括号中的参数是从页面中传过来的,比如 edit.jsp中userid:
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'index.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <form action="update.do" method="post"> <input type="hidden" name="userId" value="$user.id" /> <table> <tr> <td>用户名:</td> <td><input type="text" name="name" value="$user.name"/></td> </tr> <tr> <td>密码:</td> <td><input type="text" name="password" value="$user.password"/></td> </tr> <tr> <td colspan="2"> <input type="submit" value="提交"/> </td> </tr> </table> </form> </body> </html>下面是控制层:
package com.demo.controller; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.demo.dao.UserDao; import com.demo.entity.User; public class UpdateController extends HttpServlet protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException doPost(req, resp); protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException String ids = req.getParameter("userId").trim(); Long id = (long) 0; if (ids != null) id = Long.parseLong(ids); String name = req.getParameter("name").trim(); String password = req.getParameter("password").trim(); User user = new User(); user.setId(id); user.setName(name); user.setPassword(password); UserDao userDao = new UserDao(); userDao.updateUser(user); resp.sendRedirect("list.do");其中
String ids = req.getParameter("userId").trim();就是得到了页面中userid的值 备注:trim()方法是为了去掉前后空格
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