请求重定向与请求转发的区别

xiaoxiao2021-02-28  17

一 请求重定向与请求转发的区别       二 生活小案例       三 请求转发实例(reg.jsp->response.jsp->request.jsp) 1、reg.jsp <%@  page  language = "java"  import = "java.util.*"  contentType = "text/html; charset=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 >      < h1 > 用户注册 </ h1 >      < hr >      <%         int  number=-1;         //说明用户第一次访问页面,计数器对象还未创建         if (application.getAttribute( "counter" )== null )        {            application.setAttribute( "counter" , 0);        }        number = Integer.parseInt(application.getAttribute( "counter" ).toString());        number++;        application.setAttribute( "counter" , number);      %>      <!-- <form name="regForm" action="request.jsp" method="post"> -->      < form  name = "regForm"  action = "response.jsp"  method = "post" >      < table >        < tr >          < td > 用户名: </ td >          < td >< input  type = "text"  name = "username" /></ td >        </ tr >        < tr >          < td > 爱好: </ td >          < td >             < input  type = "checkbox"  name = "favorite"  value = "read" > 读书             < input  type = "checkbox"  name = "favorite"  value = "music" > 音乐             < input  type = "checkbox"  name = "favorite"  value = "movie" > 电影             < input  type = "checkbox"  name = "favorite"  value = "internet" > 上网          </ td >        </ tr >        < tr >           < td  colspan = "2" >< input  type = "submit"  value = "提交" /></ td >        </ tr >      </ table >      </ form >      < br >      < br >      < a  href = "request.jsp?username=李四" > 测试URL传参数 </ a >          < br >      < br >      < center >              您是第 <%= number  %> 位访问本页面的用户。      </ center >    </ body > </ html > 2、response.jsp <%@  page  language = "java"  import = "java.util.*,java.io.*"  contentType = "text/html; charset=utf-8" %> <%     response.setContentType( "text/html;charset=utf-8" );  //设置响应的MIMI类型         out.println( "<h1>response内置对象</h1>" );     out.println( "<hr>" );      //out.flush();  //解决PrintWrite对象的浏览器输出总是先于out对象输出这一问题         PrintWriter outer = response.getWriter();  //获得输出流对象     outer.println( "大家好,我是response对象生成的输出流outer对象" );      //response.sendRedirect("reg.jsp");//请求重定向      //请求重定向      //response.sendRedirect("request.jsp");      //请求转发     request.getRequestDispatcher( "request.jsp" ).forward(request, response); %> 3、request .jsp <%@   page   language = "java"   import = "java.util.*"   contentType = "text/html; charset=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 >      < h1 > request内置对象 </ h1 >      <%        request.setCharacterEncoding( "utf-8" );  //解决中文乱码问题,无法解决URL传递中文出现的乱码问题。        request.setAttribute( "password" ,  "123456" );          %>         用户名: <%= request.getParameter( "username" )  %> < br >            爱好 : <%             if (request.getParameterValues( "favorite" )!= null )            {                    String[] favorites = request.getParameterValues( "favorite" );                     for ( int  i=0;i<favorites.length;i++)                    {                       out.println(favorites[i]+ "  " );                    }                 }          %>  < br >          密码: <%= request.getAttribute( "password" )  %> < br >          请求体的MIME类型: <%= request.getContentType()  %> < br >          协议类型及版本号:   <%= request.getProtocol()  %> < br >          服务器主机名 : <%= request.getServerName()  %> < br >          服务器端口号: <%= request.getServerPort()  %> < BR >          请求文件的长度 : <%= request.getContentLength()  %> < BR >          请求客户端的IP地址: <%= request.getRemoteAddr()  %> < BR >          请求的真实路径: <%= request. getRealPath( "request.jsp" )  %> < br >          请求的上下文路径: <%= request.getContextPath()  %> < BR >                              </ body > </ html >   四 运行结果     大小: 183.4 KB 大小: 168.8 KB 大小: 58.4 KB 查看图片附件
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