【 jsp】页面传递

最新推荐文章于 2023-08-18 09:26:49 发布

Jason_xcj

最新推荐文章于 2023-08-18 09:26:49 发布

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分类专栏： JavaWeb

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首先介绍一下request共享：
test1.classTest:

package test1;

public class classTest {

private String name = null;

public classTest(){}

public void setName(String strName_p){

this.name=strName_p;

}

public String getName(){

return this.name;

}

MyJsp.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>

<%@page import="test1.classTest"%>

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>

<title>My JSP 'MyJsp.jsp' starting page</title>

<!--

-->

</head>

<body>

<jsp:useBean id="stringBean" class="test1.classTest" scope="request"/>

<jsp:setProperty name="stringBean" property="name" value="request"/>

<%request.setAttribute("aa","aa"); %>

<jsp:include page="MyJsp1.jsp"></jsp:include>

</body>

</html>

MyJsp1.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>

<%@page import="test1.classTest"%>

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>

<title>My JSP 'MyJsp1.jsp' starting page</title>

<!--

-->

</head>

<body>

<%classTest aa= (classTest)request.getAttribute("stringBean") ;%>

<%=aa.getName() %>

</body>

</html>

如果用request，要注意request的范围仅限于同一个request对象；如果使用了form的"action"或者response.sendRedirect("xxx.jsp")等调转，则不再是同一个request对象，即用request.getAttribute("name")将取不到值。
换成request.getRequestDispatcher("xxx.jsp").forward(request,response);
才能共享request中数据

所以关于request的传递必须是<jsp:include或者<jsp:forward以及
 RequestDispatcher dispatcher=request.getRequestDispatcher("../test1/MyJsp.jsp");
 dispatcher.forward(request, response);
 的形式

二session共享：

MyJsp.jsp:

<jsp:useBean id="stringBean" class="test1.classTest" scope="session"/>

<jsp:setProperty name="stringBean" property="name" value="session"/>

<%session.setAttribute("aa","aa"); %>

<a href="test2/MyJsp1.jsp">MyJsp1.jsp</a>

MyJsp1.jsp:

<%classTest aa= (classTest)session.getAttribute("stringBean") ;%>

<%=aa.getName() %>

<%=session.getAttribute("aa") %>

三application共享：

MyJsp.jsp:

<jsp:useBean id="stringBean" class="test1.classTest" scope="application"/>

<jsp:setProperty name="stringBean" property="name" value="application"/>

<%getServletContext().setAttribute("aa","aa"); %>

<a href="test2/MyJsp1.jsp">MyJsp1.jsp</a>

MyJsp1.jsp:

<%classTest aa= (classTest)getServletContext().getAttribute("stringBean") ;%>

<%=aa.getName() %>

<%=getServletContext().getAttribute("aa") %>

再介绍一下servlet和jsp页面的共享：

servlet1:

package test1;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.*;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class servlet1 extends HttpServlet {

/**

* Constructor of the object.

public servlet1() {

super();

}

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

PrintWriter out = response.getWriter();

out.println("Aa");

classTest value=new classTest();

String[] string={"aa","bb"};

value.setName("Request");

request.setAttribute("keyRequest", value);

request.setAttribute("aaa", "aaaa");

request.setAttribute("string", string);

classTest valueSession=new classTest();

valueSession.setName("Session");

HttpSession session=request.getSession();

session.setAttribute("keySession", valueSession);

session.setAttribute("bbb", "bbbb");

//session.setAttribute("string", string);

classTest valueApplication=new classTest();

valueApplication.setName("Application");

getServletContext().setAttribute("valueApplication", valueApplication);

getServletContext().setAttribute("ccc", "cccc");

RequestDispatcher dispatcher=request.getRequestDispatcher("../test1/MyJsp.jsp");

dispatcher.forward(request, response);

}

MyJsp.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>

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>

<title>My JSP 'MyJsp.jsp' starting page</title>

<!--

-->

</head>

<body>

<jsp:useBean id="keyRequest" type="test1.classTest" scope="request"></jsp:useBean>

<jsp:getProperty name="keyRequest" property="name"/>

<jsp:useBean id="valueApplication" type="test1.classTest" scope="application"></jsp:useBean>

<jsp:getProperty name="valueApplication" property="name"/>

${aaa}

${bbb}

${ccc}

${keyRequest.name}

${string[0]}

<% test1.classTest aa=(test1.classTest)session.getAttribute("keySession"); %>

<%=aa.getName() %>

<%=keyRequest.getName() %>

</body>

</html>

稍改一下serlvet
替换成：

out.println("<a href='../test1/MyJsp.jsp'>MyJsp.jsp</a>");

再看MyJsp.jsp

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>

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>

<title>My JSP 'MyJsp.jsp' starting page</title>

<!--

-->

</head>

<body>

<jsp:useBean id="keyRequest" type="test1.classTest" scope="request"/>//注意type与class的区别

<jsp:getProperty name="keyRequest" property="name"/>

<jsp:useBean id="valueApplication" type="test1.classTest" scope="application"/>

<jsp:getProperty name="valueApplication" property="name"/>//必须引入userBean

${aaa} //这样的写法简练，可以不需要前面的userBean，直接得到结果

${bbb}

${ccc}

${keyRequest.name}

${string[0]}

<% test1.classTest aa=(test1.classTest)session.getAttribute("keySession"); %>//这种形式不需要userBean但是较为麻烦

<%=aa.getName() %>

<%=keyRequest.getName() %>//这种形式引入上面的userBean

</body>

</html>

null Application

bbbb
cccc

Session
null
很明显request的结果就为null，session和application没有影响，和我们所说的jsp间的传递一样，
其实jsp也是sevlet。