String sql="select * from user where name='test'";
ResultSet rs = RegisterBean.executeQuery(sql);
if(rs.next()) {
rs.close();
out.println("<CENTER>用户存在!</CENTER>");
java.lang.IllegalStateException: Response has already been committed
at org.apache.tomcat.core.HttpServletResponseFacade.sendError(HttpServletResponseFacade.java:157)
at org.apache.jasper.runtime.JspServlet.unknownException(JspServlet.java:299)
at org.apache.jasper.runtime.JspServlet.service(JspServlet.java:377)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.tomcat.core.ServletWrapper.handleRequest(ServletWrapper.java:503)
at org.apache.tomcat.core.ContextManager.service(ContextManager.java:559)
at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:160)
at org.apache.tomcat.service.TcpConnectionThread.run(SimpleTcpEndpoint.java:338)
at java.lang.Thread.run(Thread.java:484)