Servlet学习(二)session管理隐藏域

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Servlet学习(二)session管理隐藏域

下面的示例通过隐藏域传递一个id值,修改某个值。

一.javabean代码.

package com.cdc.servlettest.bean;public class Customer {    private int id;    private String name;    private String city;    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getCity() {        return city;    }    public void setCity(String city) {        this.city = city;    }}

二.servlet代码。

package com.cdc.servlettest.servlet;import java.io.IOException;import java.io.PrintWriter;import java.util.ArrayList;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.cdc.servlettest.bean.Customer;/* * Not thread-safe. For illustration purpose only */@WebServlet(name = "CustomerServlet", urlPatterns = {         "/customer", "/editCustomer", "/updateCustomer"})public class CustomerServlet extends HttpServlet {    private static final long serialVersionUID = -20L;    private List<Customer> customers = new ArrayList<Customer>();        @Override    public void init() throws ServletException {        Customer customer1 = new Customer();        customer1.setId(1);        customer1.setName("张飞");        customer1.setCity("成都");        customers.add(customer1);                Customer customer2 = new Customer();        customer2.setId(2);        customer2.setName("刘备");        customer2.setCity("西安");        customers.add(customer2);           }        private void sendCustomerList(HttpServletResponse response)            throws IOException {        response.setContentType("text/html");        response.setCharacterEncoding("utf-8");        PrintWriter writer = response.getWriter();        writer.println("<html><head><title>客户</title></head>"                + "<body><h2>客户 </h2>");        writer.println("<ul>");        /**从初始化的集合里取出数据,显示在界面上。*/        for (Customer customer : customers) {            writer.println("<li>" + customer.getName()                   + "(" + customer.getCity() + ") ("                    + "<a href='editCustomer?id=" + customer.getId()                   + "'>修改</a>)");        }        writer.println("</ul>");        writer.println("</body></html>");            }    /****通过id值获取相应的记录*/    private Customer getCustomer(int customerId) {        for (Customer customer : customers) {            if (customer.getId() == customerId) {                return customer;            }        }        return null;    }        private void sendEditCustomerForm(HttpServletRequest request,             HttpServletResponse response) throws IOException {        response.setContentType("text/html");        response.setCharacterEncoding("utf-8");        PrintWriter writer = response.getWriter();        int customerId = 0;        try {        /**接收通过url重写传递过来的参数id的值**/            customerId =                     Integer.parseInt(request.getParameter("id"));        } catch (NumberFormatException e) {        }        Customer customer = getCustomer(customerId);        /***此表单通过post提交后,将调用此Servlet的doPost方法*/        if (customer != null) {            writer.println("<html><head>"                    + "<title>修改客户资料</title></head>"                    + "<body><h2>修改客户资料</h2>"                    + "<form method='post' "                    + "action='updateCustomer'>");            /**隐藏域,传递id**/            writer.println("<input type='hidden' name='id' value='"                     + customerId + "'/>");            writer.println("<table>");            writer.println("<tr><td>姓名:</td><td>"                     + "<input name='name' value='" +                     customer.getName().replaceAll("'", "'")                     + "'/></td></tr>");            writer.println("<tr><td>城市:</td><td>"                     + "<input name='city' value='" +                     customer.getCity().replaceAll("'", "'")                     + "'/></td></tr>");            writer.println("<tr>"                    + "<td colspan='2' style='text-align:right'>"                     + "<input type='submit' value='Update'/></td>"                     + "</tr>");            writer.println("<tr><td colspan='2'>"                    + "<a href='customer'>客户列表</a>"                     + "</td></tr>");            writer.println("</table>");            writer.println("</form></body>");        } else {            writer.println("没有此客户");        }            }    @Override    public void doGet(HttpServletRequest request,             HttpServletResponse response)            throws ServletException, IOException {        String uri = request.getRequestURI();        response.setCharacterEncoding("utf-8");        if (uri.endsWith("/customer")) {            sendCustomerList(response);        } else if (uri.endsWith("/editCustomer")) {            sendEditCustomerForm(request, response);        }    }        @Override    public void doPost(HttpServletRequest request,             HttpServletResponse response)            throws ServletException, IOException {            // update customer    response.setCharacterEncoding("utf-8");    request.setCharacterEncoding("utf-8");        int customerId = 0;        try {        /***接收隐藏域传递过来的id值*/            customerId =                     Integer.parseInt(request.getParameter("id"));        } catch (NumberFormatException e) {        }        Customer customer = getCustomer(customerId);        if (customer != null) {            customer.setName(request.getParameter("name"));            customer.setCity(request.getParameter("city"));        }        sendCustomerList(response);    }}

Servlet学习(二)__session管理__隐藏域

Servlet学习(二)__session管理__隐藏域

Servlet学习(二)session管理隐藏域

Servlet学习(二)session管理隐藏域