本文为博主原创，未经允许，不得转载：
先还原错误：
org.apache.jasper.JasperException: /WEB-INF/view/../../../../common/common1.jsp (line: 7, column: 1) Page directive must not have multiple occurrences of pageencoding
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:41)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:275)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:107)
org.apache.jasper.compiler.Validator$DirectiveVisitor.visit(Validator.java:196)
org.apache.jasper.compiler.Node$PageDirective.accept(Node.java:571)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2376)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2428)
org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2434)
org.apache.jasper.compiler.Node$Root.accept(Node.java:464)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2376)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2428)
org.apache.jasper.compiler.Validator$DirectiveVisitor.visit(Validator.java:101)
org.apache.jasper.compiler.Node$IncludeDirective.accept(Node.java:635)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2376)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2428)
org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2434)
org.apache.jasper.compiler.Node$Root.accept(Node.java:464)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2376)
org.apache.jasper.compiler.Validator.validateDirectives(Validator.java:1813)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:196)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:336)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:323)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:585)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:363)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168)
org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303)
org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1286)
org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1041)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:984)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
com.allcam.rss.system.filter.SystemFilter.doFilter(SystemFilter.java:102)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
解决及分析：
页面使用了多次页面编码。
问题所在：
页面引用公用的头，两个都使用了：pageEncoding="UTF-8"，
即：<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
去掉其他页面的pageEncoding="UTF-8",只留下一个就可以解决问题。