Go语言视频零基础入门到精通

javalearner

假如说要取一个保存在session中的Integer类型的数channelId：
String channel = null;
  if(session.getAttribute("channelId") != null)
   channel = session.getAttribute("channelId").toString();
  int channelId = 1;
  if(channel != null){
   Integer bb = Integer.parseInt(channel);
   channelId = bb.intValue();
  }
常用方法：
int channelId = Integer.parseInt((String)session.getAttribute("channelId"));
会报如下错误：
java.lang.ClassCastException: java.lang.Integer
at org.apache.jsp.admin.articleList_jsp._jspService(articleList_jsp.java:123)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.Servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at mathmodel.admin.filter.AdminLoginFilter.doFilter(AdminLoginFilter.java:39)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:595)