JSTL的fmt标签完成的国际化，后面使用框架提供的标签完成
实现中文、英文切换：
》提供两个超简洁，携带不同的变量值
》根据变量值确定对应的Locale对象
》把Locale对象放入到session中
》绑定Locale对应的资源文件。
<%@ page import="java.util.Locale" %>
<%@ page import="java.util.Date" %><%--
Created by IntelliJ IDEA.
User: dell
Date: 2019/7/23
Time: 16:36
To change this template use File | Settings | File Templates.
--%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>c
</head>
<body>
<%
Date date = new Date();
request.setAttribute("date",date);
request.setAttribute("salary",12345.67);
%>
<%
String code = request.getParameter("code");
if (code != null){
if ("en".equals(code)){
session.setAttribute("locale", Locale.US);
}else if ("zh".equals(code)){
session.setAttribute("locale",Locale.CHINA);
}
}
%>
<c:if test="${sessionScope.locale != null}">
<fmt:setLocale value="${sessionScope.locale}"/>
</c:if>
<fmt:setBundle basename="i18n"/>
<fmt:message key="key"/>:
<fmt:formatDate value="${date }" dateStyle="FULL" />
<fmt:message key="salary"/>:
<fmt:formatNumber value="${salary }" type="currency"/>
<br><br>
<a href="xxx.jsp?code=en">English</a>
<a href="xxx.jsp?code=zh">中文</a>
</body>
</html>