MVC案例之新增与修改Customer

2023-08-15 13:47:46

新增Customer

添加的流程
Add New Customer 超链接连接到 newcustomer.jsp
新建 newcustomer.jsp：

MVC案例之新增与修改Customer

在 CustomerServlet 的 addCustomer 方法中：参见注释

MVC案例之新增与修改Customer

上图一共有 2 个请求

加载页面的请求：发出请求到页面加载完成，request 结束

点击提交按钮，到 Serlvet，发出了一个 request，Serlvet 转发到 newcustomer.jsp 直到页面加载完成，整个过程一个 request

doPost(request, response) ---> request.getRequestDispatcher(path).forward(request, response);

private void addCustomer(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        // 1.获取表单参数：name address phone

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

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

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

        // 2.检验 name 是否被占用

        // 2.1调用CustomerDAO的getCountWithName(String name) 获取 name 在数据库中是否存在

        long count = customerDAO.getCountWithName(name);

        // 2.2若返回值大于0，则响应 newcustomer.jsp 页面, 通过转发的方式响应newcustomer.jsp

        if (count > 0) {

            // 2.2.1要求页面显示一个错误消息： 用户名 name已经被占用，请重新选择，

            // 在request中放入一个属性message ：用户名 name 已经被占用，请重新选择！

            // 在页面通过request.getAttribute("message")的方式显示

            request.setAttribute("message", "用户名 " + name + "已经被占用，请重新选择");

            // 2.2.2 newcustomer.jsp 的表单可以回显

            // 通过value="<%=request.getParameter("name") == null ? "" :

            // request.getParameter("name") %>"进行回显

            // 2.2.3结束方法：return

            request.getRequestDispatcher("/newcustomer.jsp").forward(request, response);

            return;

        }

        // 3.若验证通过，把表单参数封装为一个Customer 对象 customer

        Customer customer = new Customer(name, address, phone);

        // 4.调用CustomerDAO的 save(Customer customer) 执行保存操作

        customerDAO.save(customer);

        // 5.重定向的 success.jsp 页面:使用重定向可以避免表单的重复提交问题

        response.sendRedirect("success.jsp");

    }

newcustomer.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

    <%
 Object msg = request.getAttribute("message");

        if (msg != null) {
%>

    <br>
  <font color="red"><%=msg%></font>

    <br>

    <br>

    <%

        }

    %>
  <form action="addCustomer.do" method="post">

        <table>

            <tr>

                <td>CustomerNam:</td>

                <td><input type="text" name="name"

                    value="<%=request.getParameter("name") == null ? "" : request.getParameter("name")%>" /></td>

            </tr>

            <tr>

                <td>Address:</td>

                <td><input type="text" name="address"

                    value="<%=request.getParameter("address") == null ? "" : request.getParameter("address")%>" /></td>

            </tr>

            <tr>

                <td>Phone:</td>

                <td><input type="text" name="phone"

                    value="<%=request.getParameter("phone") == null ? "" : request.getParameter("phone")%>" /></td>

            </tr>

            <tr>

                <td colspan="2"><input type="submit" value="Submit" /></td>

            </tr>

        </table>

    </form>

</body>

</html>

修改：
先显示（SELECT 操作）修改的页面，再进行修改（update）

显示修改页面

Update 的超链接：<a href="edit.do?id=<%= customer.getId() %>">UPDATE</a>

edit 方法： 

private void edit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String forwardPath = "/error.jsp";// 初始值

        // 1.获取请求参数 id

        String idStr = request.getParameter("id");

        // 2.调用CustomerDAO 的 customerDAO.get(id) 获取 id 对应的Customer 对象customer

        try {

            Customer customer = customerDAO.get(Integer.parseInt(idStr));

            if (customer != null) {// 当customer为null是转到 error.jsp

                forwardPath = "/updatecustomer.jsp";

                // 3.将customer放入request 中

                request.setAttribute("customer", customer);

            }

        } catch (Exception e) {

        }

        // 4.响应updatecustomer.jsp 页面： 转发

        request.getRequestDispatcher(forwardPath).forward(request, response);

    }

JSP 页面：

获取请求域中的 Customer 对象，调用对应的字段的 get 方法来显示值。

使用隐藏域来保存要修改的 Customer 对象的 id：<input type="hidden" name="id" value=“<%= customer.getId() %>"/>

使用隐藏域来保存 oldName：<input type="hidden" name=“oldName" value=“<%= customer.getName() %>"/>

关于隐藏域：和其他的表单域一样可以被提交到服务器，只不过在额页面上不显示

提交到 update.do

CustomerServlet

package com.aff.mvcapp.servlet;

import java.io.IOException;

import java.lang.reflect.Method;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.aff.mvcapp.dao.CriteriaCustomer;

import com.aff.mvcapp.dao.CustomerDAO;

import com.aff.mvcapp.dao.impl.CustomerDAOImpl;

import com.aff.mvcapp.domian.Customer;

@WebServlet("/customerServlet")

public class CustomerServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    private CustomerDAO customerDAO = new CustomerDAOImpl();

    protected void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        doPost(request, response);

    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        // 1. 获取ServletPath: /edit.do 或 addCustomer.do

        String servletPath = request.getServletPath();

        // 2.去除 / 和 .do 得到类似于 edit 或 addCustomer 这样的字符串

        String methodName = servletPath.substring(1);

        methodName = methodName.substring(0, methodName.length() - 3);

        try {

            // 3.利用反射获取 methodName 对应的方法

            Method method = getClass().getDeclaredMethod(methodName, HttpServletRequest.class,

                    HttpServletResponse.class);

            // 4.利用反射调用对应的方法

            method.invoke(this, request, response);

        } catch (Exception e) {

            // e.printStackTrace();

            // 可以有一些响应

            response.sendRedirect("error.jsp");

        }

    }

    private void addCustomer(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        // 1.获取表单参数：name address phone

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

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

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

        // 2.检验 name 是否被占用

        // 2.1调用CustomerDAO的getCountWithName(String name) 获取 name 在数据库中是否存在

        long count = customerDAO.getCountWithName(name);

        // 2.2若返回值大于0，则响应 newcustomer.jsp 页面, 通过转发的方式响应newcustomer.jsp

        if (count > 0) {

            // 2.2.1要求页面显示一个错误消息： 用户名 name已经被占用，请重新选择，

            // 在request中放入一个属性message ：用户名 name 已经被占用，请重新选择！

            // 在页面通过request.getAttribute("message")的方式显示

            request.setAttribute("message", "用户名 " + name + "已经被占用，请重新选择");

            // 2.2.2 newcustomer.jsp 的表单可以回显

            // 通过value="<%=request.getParameter("name") == null ? "" :

            // request.getParameter("name") %>"进行回显

            // 2.2.3结束方法：return

            request.getRequestDispatcher("/newcustomer.jsp").forward(request, response);

            return;

        }
// 3.若验证通过，把表单参数封装为一个Customer 对象 customer

        Customer customer = new Customer(name, address, phone);

        // 4.调用CustomerDAO的 save(Customer customer) 执行保存操作

        customerDAO.save(customer);

        // 5.重定向的 success.jsp 页面:使用重定向可以避免表单的重复提交问题

        response.sendRedirect("success.jsp");

    }

    private void edit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   String forwardPath = "/error.jsp";// 初始值
// 1.获取请求参数 id

        String idStr = request.getParameter("id");

        // 2.调用CustomerDAO 的 customerDAO.get(id) 获取 id 对应的Customer 对象customer

        try {

            Customer customer = customerDAO.get(Integer.parseInt(idStr));
if (customer != null) {// 当customer为null是转到 error.jsp

                forwardPath = "/updatecustomer.jsp";
// 3.将customer放入request 中

                request.setAttribute("customer", customer);

            }

        } catch (Exception e) {

        }

        // 4.响应updatecustomer.jsp 页面： 转发

        request.getRequestDispatcher(forwardPath).forward(request, response);

    }

    private void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        // 1.获取表单参数：id,name,addres, phone, oldName

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

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

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

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

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

        // 2.检查name是否被占用

        // 2.比较name和oldName 是否相同，若相同说明 name可用

        // 2.1若不相同， 则调用CustomerDAO 的 getCountWithName(String name) 获取 name在数据库中是否存在

        if (!oldName.equalsIgnoreCase(name)) {

            long count = customerDAO.getCountWithName(name);

            if (count > 0) {

                // 2.2若返回值大于0，则响应 updatecustomer.jsp 页面,

                // 通过转发的方式响应updatecustomer.jsp

                // 2.2.1要求页面显示一个错误消息： 用户名 name已经被占用，请重新选择，

                // 在request中放入一个属性message ：用户名 name 已经被占用，请重新选择！

                // 在页面通过request.getAttribute("message")的方式显示

                request.setAttribute("message", "用户名" + name + "已经被占用，请重新选择！");

                // 2.2.2 updatecustomer.jsp 的表单可以回显

                // address, phone 显示提交表单的新的值，而 name 显示oldName， 而不是新提交的 name

                // 2.2.3结束方法：return

                request.getRequestDispatcher("/updatecustomer.jsp").forward(request, response);

                return;

            }

        }

        //3.若验证通过，则把表单参数封装为一个Customer 对象 customer
  Customer customer  = new Customer(name, address, phone);

        customer.setId(Integer.parseInt(id));//表单过来的 安全的

        //4.调用CustomerDAO 的 update(Customer customer) 执行更新操作

        customerDAO.update(customer);

        //5.重定向到    query.do

        response.sendRedirect("query.do");

    }


    private void query(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

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

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

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

        CriteriaCustomer cc = new CriteriaCustomer(name, address, phone);

        // 1.调用 CustomerDAO 的 getForListWithCriteriaCustomer() 得到 Customer 的集合

        List<Customer> customers = customerDAO.getForListWithCriteriaCustomer(cc);

        // 2.把 Customer 的集合放入 request 中

        request.setAttribute("customers", customers);

        // 3.转发页面到 index.jsp 中( 不能使用重定向)

        request.getRequestDispatcher("/index.jsp").forward(request, response);

    }

    private void delete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String idstr = request.getParameter("id");

        int id = 0;

        // try-catch的作用 ， 防止恶意的输入， idStr 不能转为int类型，若出异常 id直接为0

        try {

            id = Integer.parseInt(idstr);

            customerDAO.delete(id);

        } catch (Exception e) {

        }

        response.sendRedirect("query.do");

    }

}

updatecustomer.jsp

<%@page import="com.aff.mvcapp.domian.Customer"%>

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

    <%

        Object msg = request.getAttribute("message");

        if (msg != null) {

    %>

    <br>

    <font color="red"><%=msg%></font>

    <br>

    <br>

    <%

        }

    %>

    <%

        String id = null;

        String oldName = null;

        String name = null;

        String address = null;

        String phone = null;
  Customer customer = (Customer) request.getAttribute("customer");
if(customer != null){

            id = customer.getId()+"";

            name = customer.getName();

            oldName = customer.getName();

            address = customer.getAddress();

            phone = customer.getPhone();
 }else{

            id = request.getParameter("id");//旧的

            name = request.getParameter("oldName");//旧的

            oldName = request.getParameter("oldName");//旧的

            address = request.getParameter("address");//新的

            phone = request.getParameter("phone");//新的

        }

    %>

    <form action="update.do" method="post">

        <input type="hidden" name="id" value="<%=id%>" /> <input

            type="hidden" name="oldName" value="<%=oldName%>" />

        <table>

            <tr>

                <td>CustomerNam:</td>

                <td><input type="text" name="name"
 value="<%=name%>" /></td>

            </tr>

            <tr>

                <td>Address:</td>

                <td><input type="text" name="address"
 value="<%=address%>" /></td>

            </tr>

            <tr>

                <td>Phone:</td>

                <td><input type="text" name="phone"
 value="<%=phone%>" /></td>

            </tr>

            <tr>

                <td colspan="2"><input type="submit" value="Submit" /></td>

            </tr>

        </table>

    </form>

</body>

</html>

index.jsp

<%@page import="com.aff.mvcapp.domian.Customer"%>

<%@page import="java.util.List"%>

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

<script type="text/javascript" src="scripts/jquery-1.12.3.js"></script>

<script type="text/javascript">

    $(function() {

        $(".delete").click(function() {

            //找到tr的第二个td也就是name，再获取它的value值

            var content = $(this).parent().parent().find("td:eq(1)").text();

            var flag = confirm("确定要删除" + content + "的信息吗")

            return flag;

        });

    });

</script>

</head>

<body>

    <form action="query.do" method="post">

        <table>

            <tr>

                <td>CustomerNam:</td>

                <td><input type="text" name="name" /></td>

            </tr>

            <tr>

                <td>Address:</td>

                <td><input type="text" name="address" /></td>

            </tr>

            <tr>

                <td>Phone:</td>

                <td><input type="text" name="phone" /></td>

            </tr>

            <tr>
   <td><input type="submit" value="Query" /></td>

              <td><a href="newcustomer.jsp">Add New Customer</a></td>

            </tr>

        </table>

    </form>

    <br />

    <br />

    <br />

    <br />

    <%

        List<Customer> customers = (List<Customer>) request.getAttribute("customers");

        if (customers != null && customers.size() > 0) {
%>

    <hr>

    <br>

    <br>

    <table border="1" cellpadding="10" cellspacing="0">

        <tr>

            <td>ID</td>

            <td>CustomersName</td>

            <td>Address</td>

            <td>Phone</td>

            <td>UPDATE\DELETE</td>

        </tr>

        <%
      for (Customer customer : customers) {
%>

        <tr>

            <td><%=customer.getId()%></td>

            <td><%=customer.getName()%></td>

            <td><%=customer.getAddress()%></td>

            <td><%=customer.getPhone()%></td>
            <td><a href="edit.do?id=<%=customer.getId()%>">UPDATE</a>

                <a href="delete.do?id=<%=customer.getId()%>" class="delete">DELETE</a>

            </td>

        </tr>

        <%

            }

        %>

    </table>

    <%

        }

    %>

</body>

</html>
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