How to write java in jsp

How to write java in jsp

You can write Java code in jsp. The specific writing method is introduced below. I hope it will help You guys are helpful.

Writing

● JSP declaration statement: <%!Declaration statement%>, usually declares global variables, constants, Methods, classes, note: the variables declared here are global

● JSP Scriptlet: <%java code%>, which can include local variables and java statements

● JSP expression: <%=java code%>, <%=variable%> is the abbreviation of <% out.println(variable) %>, please note : The expression here cannot be followed by a semicolon

(recommended tutorial: java tutorial)

Three instructions are defined in jsp2.0: page instruction, include instruction, and taglib instruction.

1. Regarding the page command, what we usually see most is this:

<%@page contentType="text/html;charset=gb2312" import="java.util.Date"%>

Mainly used for: setting encoding and importing jar packages

2. About The include directive is used to introduce other jsp pages. The jsp engine will translate two jsps into one servlet, so it is also called static introduction

3. Regarding the taglib directive, it defines a tag library and its customization The prefix of the label. For example, we commonly use c:foreach. First import the jstl package, and then add this tag to the jsp:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

Then you can use c:foreach

Example:

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%  
	 String M=session.getAttribute("sysname").toString(); //从session里把值拿出来，并赋值给M  
%> <
div class = "navbar-header pull-left" >
    <
    a href = "javascript:;"
class = "navbar-brand" >
    <
    small >
    <
    i class = "fa fa-leaf" > < /i>
<%=M%> <
/small> <
/a> <
/div>

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