我是新手想请各位高手给点帮助
我是新手自己编写个小程序但有错误,请大家帮忙看看
%@ page contentType="text/html;charset=GBK" %> <%@include file="a.html"%> <html> <head> <title>表单和JSP结合</title> </head> <body> <center> <h1>玩具店</h1> <form action="wan.jsp"method="get"> <p><input type="checkbox" name="wan1"value="绒毛熊">绒毛熊 <input type="checkbox" name="wan1"value="米老鼠">米老鼠 <p><input type="checkbox" name="wan1"value="小狗">小狗 <input type="checkbox" name="wan1"value="唐老鸭">唐老鸭 <p><input type="submit"value="购买"></p> </form> <p>现在购买的商品有: <p><% String aa[]=request.getParameterValues("wan1"); if(session.getAttribute("wan2") == null) { session.setAttribute("wan2","ok"); } session.setAttribute("wan2",session.getAttribute("wan2") +aa); out.println(session.getAttribute("wan2") + "<br>"); %> <a href="main.jsp">退出</a> </html> type Exception report message description The server encountered an internal error () that prevented it from fulfilling this request. exception org.apache.jasper.JasperException: Unable to compile class for JSP An error occurred at line: -1 in the jsp file: null Generated servlet error: [javac] Since fork is true, ignoring compiler setting. [javac] Compiling 1 source file [javac] Since fork is true, ignoring compiler setting. [javac] E:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\jsp作业\wan_jsp.java:99: operator + cannot be applied to java.lang.Object,java.lang.String[] [javac] session.setAttribute("wan2",session.getAttribute("wan2") +aa); [javac] ^ [javac] 1 error