转发、隐藏JSP、URL地址

一、转发参数：

1.将jsp里面的参数通过LoginServlet转到PageSelvert：

@WebServlet(“/login”)public  class  LoginServlet  extends  HttpServlet{protected void dopost(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{   //转发到PageServlet去Request.getRequestDispatcher(“/page”),forword(request,reapomse);  }}@WebServlet(“page”)public  class  PageServlet  extends  HttpServlet{protected void dopost(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{ String usename = request.getParameter(“usename”);String password = request.getParameter(“password”);System.out.pritln(usename);System.out.pritln(passworrd);}}

2.将LoginServlet里面的存放的值带给PageServlet中去：

@WebServlet(“/login”)Public  class  LoginServlet  extends  HttpServlet{Protected  void  dopost(HttpServletRequest  request,HttpServletResponse  response){//在request对象里，设置属性值，只要是同一个request对象才能获得此数据（所以转发可以，重定向不行，重定向是两个）//将email带过去(只能在前面，如是在传的后（getRequestDisPatcher后面），则得不到)Request.setAttribute(“email”,”[e-mail]”);Request.getRequestDisPatcher(“/page”),forword(request,response);}}  @WebServlet(“/page”)Public class PageServlet extends HttpServlet{Protected void dopost(HttpServletRequest  request,HttpServletResponse  response){//得到[e-mail] email = (String)request.getAttribute(“email”);//删除email值Request.removeAttribute(“email”);//拿到所有的名字Request.getAttributeNames();String usename = request.getParameter(“usename”);String password = request.getParameter(“password”);}}

** 转发参数：** removeAttribute 删除 getAttributeNames 拿到所有的名字 setAttribute 设置值 getAttribute 得到值

request response 他们的生命周期，就在请求和响应之间结束。

二、隐藏JSP:

可以将JSP放入WEB-INF目录，以后只能用转发来访问以下的JSP

<welcome-file-list><-- 欢迎页面是转发机制的跳转 --><welcome-file>index.jsp</welcome-file></welcome-file-list>

目的：隐藏jsp 将访问页面改成如下：

<welcome-file-list><welcome-file>/WEB-INF/pages/index.jsp</welcome-file></welcome-file-list>

前面加“/”直接到以其为根目录的地方

//admin为一个虚拟夹子@WebServlet("/admin/test")public class TestServlet entends HttpServlet{protected void deGet(HttpServletQuest req,HttpServletResponse resp)throws ServletException,IOEception{resp.sendRedirect("index.jsp");}}

想访问到的3种方法：

//”..”代表在index.jsp目录下向上跳一个目录resp.sendRedirect("../index.jsp");

System.out.println(req.getContextPath());//servlet7_urlresp.sendRedirect(req.getContextPath()+"/index.jsp");

resp.sendRedirect(req.getContextPath() + "/");

三、乱码问题：

Tomcat7 版本转换乱码需要看方法来转get string类转码 post就直接设置编码就可以了

String s=req.getParament("text");        ↓

<from actoin="lm" method="get">

System.out.println(new String(s.getBytes(ISO-8859),"utf-8"));req,setCharacterEncoding("UTF-8");String s=req.getParamenter("test");        ↓

<from actoin="lm" method="post">

System.out.println(s);

Tomcat8 版本就不需要半段方法，直接设置转码就可

req.setCharacterEncoding("UTF-8");String s=req.getParameter("test");System.out.println(s);

如果不转码，直接打印，就会出现乱码，如下图：

如果想将一个Servlet里面的字符传到另一个Servlet中去，需要进行转码，如：

Request.sendRedirect(text1?name=”狗子”)；

此时应写成：

Text0Servlet:Request.sendRedirect(“text1?name=”+URLEncode.encode(“狗子”));Text1Servlet://tomcat8Request.setCharacterEncoding(“UTF-8”);//tomcat 7String  s=new String(request.getParameter(“name”).getBytes(“ISO-8859-1”),”utf-8”);System.out.println(request.getParameter(“name”));

resp.sendRedirect("test1?name="+URLEncoder.encode("多态","UTF-8"));                           ↓req.setCharacterEncoding("UTF-8");//String s=new String(req.getParameter("name").getBytes("ISO-8859-1"),"UTF-8")System.out.println(req.getParameter);