问题

使用了两种引用方式
第一种无乱码

<%@ include file="header.htmlf" %> 

第二种乱码

<jsp:include page="header.htmlf" flush="true"/>

解决

在web.xml文件中添加

<jsp-config>
    <jsp-property-group>
    <description>html encoding example</description>
    <display-name>JSPConfiguration</display-name>
    <url-pattern>*.htmlf</url-pattern>
    <el-ignored>true</el-ignored>
    <page-encoding>UTF-8</page-encoding>
    <scripting-invalid>false</scripting-invalid>
    <include-prelude></include-prelude>
    <include-coda></include-coda>
    </jsp-property-group>
</jsp-config>