插入mysql数据库时 报500

数据都能插入数据库,也都是中文,但我设置的是插入成功跳转到成功页面,但去报500错,什么原因~~??

HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /pages/answer.jsp at line 17

14:    String name=request.getParameter("userName");
15:    String them=request.getParameter("userThem");
16:    String user=request.getParameter("user");
17:    name=new String(name.getBytes("ISO_8859_1"),"GBK");
18:    them=new String(them.getBytes("ISO_8859_1"),"GBK");
19:    user=new String(user.getBytes("ISO_8859_1"),"GBK");
20:    %>


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.