Base-Jsp-12-Jsp翻译为servlet

最新推荐文章于 2021-07-07 10:36:48 发布

翻译最新推荐文章于 2021-07-07 10:36:48 发布 · 911 阅读

文章标签：

#null #import #string #scripting #application #jsp

博客给出了一个JSP示例代码，包含页面设置、方法定义等内容。同时展示了将该JSP转化后的Servlet代码，涉及类定义、方法实现、JSP隐含变量处理等，体现了JSP与Servlet之间的转换关系。

ª 事例：

<%@ page language=”java” contentType=”text/html”%>

<%@ page import=”java.util.Date”%>

<%!

Private String getGreeting()

{

Date now = new Date();

String greeting = null;

If( now.getHours()<12)

{

greeting = “Good morning”;

}

else if(now.getHours()<18)

{

gretting = “Good day”;

}

else

{

greeting = “good evening”;

}

Return greeting;

}

<html>

<head>

<title>All Scripting Elements</title>

</head>

<%=ge tGreeting()%>

<%if (request.g etParameter(“name”) = = null) {%>

Stranger!

<%} else {%>

Partner

<%}%>

How are you?

</body>

</html>

ª 转化后的servlet

import java.util.Date;

import javax.servlet.*;

import javax.servlet.http.*;

import javax.servlet.jsp.*;

public class allinone$jsp extends HttpJspBase

{

//声明元素原封不动的插入到了类的顶级

//声明元素中的方法没有访问JSP隐式变量的权限，如果要访问，必须作为参数传给该方法

Private String getGreeting()

{

Date now = new Date();

String greeting = null;

If( now.getHours()<12)

{

greeting = “Good morning”;

}

else if(now.getHours()<18)

{

gretting = “Good day”;

}

else

{

greeting = “good evening”;

}

return greeting;

}

public void _jspService(HttpServletRequest request,

HttpServletResponse response)

throws java.io.IOException,ServletException

{

//JSP隐含变量都是局部变量

JspFactory _jspxFactory = null;

PageCOntext pageCOntext = null;

HttpSession session = null;

ServletContext application = null;

ServletConfig config = null;

JspWriter out = null;

Object page = this;

String _value = null;

try

{

_jspFactory = JspFactory.getDefaultFactory();

response.setContentType("text/html");

pageContext =

_jspxFactory.getPageContext(this,request,response,

"",true,8129,true);

application =pageContext.getServletContext();

config = pageContext.getServletConfig()l

session =pageContext.getSession();

out = pageContext.getOut();

out.write("/r/n");

out.write("/r/n<html>/r/n<head>/r/n");

out.write("<title>all scription Elements<title>/r/n");

out.write("</head>/r/n<body bgcolor=/"white/">/r/n");

//表达式元素也原封不动的插入，所以不应该在JSP表达式末尾使用分号的原因

out.print(getGreeting());

out.write("/r/n");

if(request.getParameter("name") ==null)

{

out.write("/r/n stranger! /r/n");

}

else

{

out.write("/r/n partner! /r/n");

}

out.write("/r/n How are you? /r/n");

out.write("</body>/r/n</html>/r/n");

}

catch(Throwable t)

{

if(out !== null & out.getBufferSize() !=0)

{

out.clearBuffer();

}

if(pageContext != null)

{

pageContext.handlePageException(t);

}

finally

{

if(_jspxFactory != null)

_jspxFactory.releasePageCOntext(pageContext);

}