Java EE WEB工程师培训-JDBC+Servlet+JSP整合开发之13.Form表单处理(2)-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_33748818/article/details/85134204

本文介绍了一个基于HTML和Servlet的简单用户注册系统的实现过程，包括表单元素的使用、如何通过Servlet接收并处理表单数据，以及如何读取所有参数名称等关键步骤。

–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#################

看下radio选项

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" >
         < ! --<link rel="stylesheet" type="text/css" href="./styles.css">-->
     </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 >
        用户性别： < input type ="radio" name ="gender" value ="male" >男
                         < input type ="radio" name ="gender" value ="female" >女
                         < input type ="radio" name ="gender" value ="secret" >保密 < 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");
                String gender = request.getParameter( "gender");
                 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("gender:"+gender);
                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

–读取所有参数名称
• Enumeration names = request.getParameterNames();

RegisterServlet.java

package com.michael.servletform;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
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");
                String gender = request.getParameter("gender");
                if(hobby!=null&&hobby.length>0){
                        for(int i=0;i<hobby.length;i++){
                                System.out.println(hobby[i]);
                        }
                }
                */
                Enumeration enu = request.getParameterNames();
                 while(enu.hasMoreElements()){
                        String name = (String) enu.nextElement();
                         if(name.equals( "hobby")){
                                String[] hobby = request.getParameterValues( "hobby");
                                 if(hobby!= null&&hobby.length>0){
                                         for( int i=0;i<hobby.length;i++){
                                                System.out.println(hobby[i]);
                                        }
                                }
                        }
                        String value = request.getParameter(name);
                        System.out.println(name+ ":"+value);
                }
                 /*
                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("gender:"+gender);
                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
        }
}

测试下

• 实例
–注册会员

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" >
         < ! --<link rel="stylesheet" type="text/css" href="./styles.css">-->
     </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 >
        用户性别： < input type ="radio" name ="gender" value ="male" >男
                         < input type ="radio" name ="gender" value ="female" >女
                         < input type ="radio" name ="gender" value ="secret" >保密 < br >
        用户职位： < select name ="position" >
                         < option value ="CEO" >CEO </option>
                         < option value ="CFO" >CFO </option>
                         < option value ="CTO" >CTO </option>
                         </select> < br >
        用户简历： < textarea rows ="5" cols ="20" name ="resume" > </textarea>
         < 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 >

RegisterServlet.java