Java EE WEB工程师培训-JDBC+Servlet+JSP整合开发之13.Form表单处理(1)

2022-02-03 23:18:54

–Form 表单简介
–创建并提交表单
–使用Servlet处理表单
• 读取单个请求参数
• 读取多个表单
• 读取所有参数名称
–实例
• 注册会员

###############Michael分割线#################

–Form 表单简介
• 表单是web程序和用户交互的主要途径之一，例如：搜索引擎、用户登录、注册等操作都离不开表单的使用
• 常用表单元素
–input
» text
» password
» radio
» checkbox
» hidden
» file
» button
» reset
» submit
–select
» option
–textarea

• 创建并提交表单
–一个简单的表单（例如：登录），如下所示

Java EE WEB工程师培训-JDBC+Servlet+JSP整合开发之13.Form表单处理(1)

–当单击“登录”按钮时表单被提交

• 使用Servlet处理表单
–读取单个请求参数
• String user = request.getParameter(“user”);

RegisterServlet.java

package com.michael.servletform;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class RegisterServlet extends HttpServlet {
        /**
         * Constructor of the object.
         */
        public RegisterServlet() {
                super();
        }
        /**
         * Destruction of the servlet. <br>
         */
        public void destroy() {
                super.destroy(); // Just puts "destroy" string in log
                // Put your code here
        }
        /**
         * The doGet method of the servlet. <br>
         *
         * This method is called when a form has its tag value method equals to get.
         *
         * @param request the request send by the client to the server
         * @param response the response send by the server to the client
         * @throws ServletException if an error occurred
         * @throws IOException if an error occurred
         */
        public void doGet(HttpServletRequest request, HttpServletResponse response)
                        throws ServletException, IOException {
                String username = request.getParameter("username");
                String password = request.getParameter("password");
                response.setContentType("text/html");
                PrintWriter out = response.getWriter();
                out
                                .println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
                out.println("<HTML>");
                out.println("    <HEAD><TITLE>A Servlet</TITLE></HEAD>");
                out.println("    <BODY>");
                out.println("username:"+username);
                out.println("username:"+password);
                out.println("    </BODY>");
                out.println("</HTML>");
                out.flush();
                out.close();
        }
        /**
         * The doPost method of the servlet. <br>
         *
         * This method is called when a form has its tag value method equals to post.
         *
         * @param request the request send by the client to the server
         * @param response the response send by the server to the client
         * @throws ServletException if an error occurred
         * @throws IOException if an error occurred
         */
        public void doPost(HttpServletRequest request, HttpServletResponse response)
                        throws ServletException, IOException {
                doGet(request,response);
        }
        /**
         * Initialization of the servlet. <br>
         *
         * @throws ServletException if an error occure
         */
        public void init() throws ServletException {
                // Put your code here
        }
}

register.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>register.html</title>
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="this is my page">
        <meta http-equiv="content-type" content="text/html; charset=UTF-8">
        
    </head>
    <body>
        <form action="/Servlet_Form/servlet/RegisterServlet" method="post">
        用户名称：<input type="text" name="username"><br>
        用户密码：<input type="password" name="password"><br>
        <input type="submit" value="注册">
    </body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
        xmlns="http://java.sun.com/xml/ns/j2ee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <servlet>
        <description>This is the description of my J2EE component</description>
        <display-name>This is the display name of my J2EE component</display-name>
        <servlet-name>RegisterServlet</servlet-name>
        <servlet-class>com.michael.servletform.RegisterServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>RegisterServlet</servlet-name>
        <url-pattern>/servlet/RegisterServlet</url-pattern>
    </servlet-mapping>
</web-app>

测试

–读取多个表单
• String[] hobby = request.getParameterValues(“hobby”);

register.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>register.html</title>
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="this is my page">
        <meta http-equiv="content-type" content="text/html; charset=UTF-8">
        
    </head>
    <body>
        <form action="/Servlet_Form/servlet/RegisterServlet" method="post">
        用户名称：<input type="text" name="username"><br>
        用户密码：<input type="password" name="password"><br>
        用户爱好：<input type="checkbox" name="hobby" value="1">游泳
                        <input type="checkbox" name="hobby" value="2">足球<br>
        <input type="submit" value="注册">
    </body>
</html>

RegisterServlet.java

package com.michael.servletform;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class RegisterServlet extends HttpServlet {
        /**
         * Constructor of the object.
         */
        public RegisterServlet() {
                super();
        }
        /**
         * Destruction of the servlet. <br>
         */
        public void destroy() {
                super.destroy(); // Just puts "destroy" string in log
                // Put your code here
        }
        /**
         * The doGet method of the servlet. <br>
         *
         * This method is called when a form has its tag value method equals to get.
         *
         * @param request the request send by the client to the server
         * @param response the response send by the server to the client
         * @throws ServletException if an error occurred
         * @throws IOException if an error occurred
         */
        public void doGet(HttpServletRequest request, HttpServletResponse response)
                        throws ServletException, IOException {
                String username = request.getParameter("username");
                String password = request.getParameter("password");
                String[] hobby = request.getParameterValues("hobby");
                if(hobby!=null&&hobby.length>0){
                        for(int i=0;i<hobby.length;i++){
                                System.out.println(hobby[i]);
                        }
                }
                response.setContentType("text/html");
                PrintWriter out = response.getWriter();
                out
                                .println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
                out.println("<HTML>");
                out.println("    <HEAD><TITLE>A Servlet</TITLE></HEAD>");
                out.println("    <BODY>");
                out.println("username:"+username);
                out.println("password:"+password);
                out.println("    </BODY>");
                out.println("</HTML>");
                out.flush();
                out.close();
        }
        /**
         * The doPost method of the servlet. <br>
         *
         * This method is called when a form has its tag value method equals to post.
         *
         * @param request the request send by the client to the server
         * @param response the response send by the server to the client
         * @throws ServletException if an error occurred
         * @throws IOException if an error occurred
         */
        public void doPost(HttpServletRequest request, HttpServletResponse response)
                        throws ServletException, IOException {
                doGet(request,response);
        }
        /**
         * Initialization of the servlet. <br>
         *
         * @throws ServletException if an error occure
         */
        public void init() throws ServletException {
                // Put your code here
        }
}

测试一下

hobby输出到控制台了

##########Michael分割线################

附件：http://down.51cto.com/data/2353099

本文转自redking51CTO博客，原文链接：http://blog.51cto.com/redking/168542，如需转载请自行联系原作者

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