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”,”123456@163.com”); Request.getRequestDisPatcher(“/page”),forword(request,response); } } @WebServlet(“/page”) Public class PageServlet extends HttpServlet{ Protected void dopost(HttpServletRequest request,HttpServletResponse response){ //得到[email protected] String 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_url resp.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: //tomcat8 Request.setCharacterEncoding(“UTF-8”); //tomcat 7 String 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);
时间: 2024-08-24 16:03:21