2020-03-24

JSP

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"

    pageEncoding="UTF-8"%>

Insert title here

<%

  pageContext.setAttribute("name","张三");

  request.setAttribute("name","李四");

  session.setAttribute("name","王五");

  application.setAttribute("name", "赵六");

%>

当前页面获取值

<%= pageContext.getAttribute("name") %>

<%= request.getAttribute("name") %>

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

<%= application.getAttribute("name")%>

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"

    pageEncoding="ISO-8859-1"%>

Insert title here

 

获取四个范围的数据

  <%= pageContext.getAttribute("name") %>

  <%= request.getAttribute("name") %>

  <%= pageContext.getAttribute("name",pageContext.REQUEST_SCOPE) %>

  <%= session.getAttribute("name") %>

  <%= pageContext.getAttribute("name",pageContext.REQUEST_SCOPE) %>

  <%= application.getAttribute("name") %>

  <%= pageContext.getAttribute("name",pageContext.APPLICATION_SCOPE) %>

<%

  pageContext.setAttribute("name","张三");

  pageContext.setAttribute("name","李四", pageContext.REQUEST_SCOPE);

  pageContext.setAttribute("name","李四", pageContext.REQUEST_SCOPE);

  pageContext.setAttribute("name","李四", pageContext.AALICATION_SCOPE);

%>

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"

    pageEncoding="ISO-8859-1"%>

Insert title here

 

JSP的动作标签;转发

 

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"

    pageEncoding="ISO-8859-1"%>

Insert title here

demo4.jsp

<%= request.getParameter("name") %>

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"

    pageEncoding="ISO-8859-1"%>

Insert title here

EL执行运算

<%

  pageContext.setAttribute("n1",10);

  pageContext.setAttribute("n2",20);

%>

${ n1 + n2 + n3 }

执行算数运算

${ n1 < n2 } -- ${ n1 lt n2 }

${ n1 > n2 } -- ${ n1 gt n2 }

${ n1 == n2 } -- ${ n1 eq n2 }

${ n1 >= n2 } -- ${ n1 ge n2 }

${ n1 <= n2 } -- ${ n1 le n2 }

${ n1 != n2 } -- ${ n1 ne n2 }

执行逻辑运算

<%

  pageContext.setAttribute("n3","30");

  pageContext.setAttribute("n4","40");

%>

${ (n1 < n2) && (n3 < n4) -- ${ (n1 < n2) and (n3 < n4) }

${ (n1 < n2) || (n3 < n4) -- ${ (n1 < n2) or (n3 < n4) }

${ !(n1 < n2) } -- ${ not (n1 < n2) }

执行三元算

${ n1 < n2 ? "n1小于n2" : "n1不小于n2" }

空运算符

${ empty user }

${ not empty user }

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