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  • Jsp内置对象和EL隐藏(内置)对象

      JSP中的内置对象一共有九个, 由于有的不太常用, 所以总是记不住, 从Sun公司的网站上找到的PDF文档, 把这一部分放在这里, 以备随时查用:
        JSP九个内置对象:
    Implicit Objects for Scriptlets
    (JSP Scriplets中的隐含对象)
    Type
    (对应类型)
    Scope
    (范围)
     Some Useful Methods (see class or interface for others)
    (常用的方法)
    1 request Subclass of javax.servlet.ServletRequest Request getAttribute, getParameter, getParameterNames, getParameterValues, setAttribute
    2 response Subclass of javax.servlet.ServletResponse Page Not typically used by JSP page authors
    3 pageContext javax.servlet.jsp.PageContext Page findAttribute, getAttribute, getAttributesScope, getAttributeNamesInScope, setAttribute
    4 session javax.servlet.http.HttpSession Session getAttribute, getId, setAttribute
    5 application javax.servlet.ServletContext Application getAttribute, getMimeType, getRealPath, setAttribute
    6 out javax.servlet.jsp.JspWriter Page clear, clearBuffer, flush, getBufferSize, getRemaining
    7 config javax.servlet.ServletConfig Page getInitParameter, getInitParameterNames
    8 page java.lang.Object Page Not typically used by JSP page authors
    9 exception java.lang.Throwable Page getMessage, getLocalizedMessage, printStackTrace, toString
     
    JSP十一个用于EL表达式的隐含(内置)对象:
    Implicit Objects for EL
    Expressions
    用于EL表达式的隐含对象
    Type
    类型
    Description
    具体说明
    pageContext javax.servlet.jsp.PageContext The context for the JSP page. Provides access to various objects, including servletContext, session, request, and response.
    pageScope java.util.Map Maps page-scoped variable names to their values.
    requestScope java.util.Map Maps request-scoped variable names to their values.
    sessionScope java.util.Map Maps session-scoped variable names to their values.
    applicationScope java.util.Map Maps application-scoped variable names to their values.
    param java.util.Map Maps a request parameter to a single String parameter value (obtained by calling ServletReqwuest.getParameter(String name)).
    paramValues java.util.Map Maps a request parameter name to an array of String values for that parameter name (obtained by calling ServletRequest.getParameterValues(String name)).
    header java.util.Map Maps a request header name to a single String header value (obtained by calling ServletRequest.getHeader(String name)).
    headerValues java.util.Map Maps a request header name to an array of String values for that header (obtained by calling ServletRequest.getHeaders(String)).
    coookie java.util.Map Maps a cookie name to a single Cookie object. Cookies are retrieved according to the semantics of HttpServletRequest.getCookies(). If the same name is shared by multiple cookies, an implementation must use the first one encountered in the array of Cookie objects returned by the getCookies() method. However, the ordering of cookies is currently unsspecified in the Servlet specification.
    initParam java.util.Map Maps a context initialization parameter name to a String parameter value (obtained by calling ServletContext.getInitparameter(String name)).
     
     
    EL表达式: ${requestScope.product.productId }
    可换成Jsp: <%= request.getParamenter("product").productId %>
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  • 原文地址:https://www.cnblogs.com/hhls/p/5817688.html
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