系统输出如下：
Line183
Line192
sqlbean.executeQuery:[Sybase][ODBC Driver][Adaptive Server Anywhere]Database server rejected connect
ion: too many connections to database
Line194
Line196
in LoginComponent.getComponentData(),catch SQLException.
java.lang.NullPointerException

源码如下：
                            sqlbean con = new sqlbean();
                            String strSql = "select * from dgkt_user where name='" + uid + "'";
                            try{
                                ResultSet rs1 = con.executeQuery(strSql);
                               
                                //表dgkt_user中没有此用户，则新增一条记录。tie（权限）从dgkt_groupTie中取得。
                                if (!rs1.next())
                                {
                                    String group = "";
                                    //insert code here to use uid get group
                                    group = "用户组一";
                                    strSql = "select tie from dgkt_groupTie where groupName='" + group + "'";
                                    System.out.println("Line192");
                                    sqlbean con1 = new sqlbean();
                                    ResultSet rs2 = con1.executeQuery(strSql);
                                    System.out.println("Line194");
                                    String tie = "";
                                    System.out.println("Line196");
                                    if (rs2.next())
                                    {
                                        tie = rs2.getString("tie");
                                    }else{
                                        System.out.println("表dgkt_groupTie中的数据有误，请检查后更正。");
                                    }
                                    System.out.println("Line203");
                                    rs2.close();
                                    con1.close();
                                    //向dgkt_user表中插入该记录
                                    strSql = "Insert into dgkt_user(name,tie,pw,nick,privacy)values('" + uid + "','" + tie + "','" + pwd + "','未知','未知')";
                                    System.out.println("Line207");
                                    sqlbean con2 = new sqlbean();
                                    con2.executeInsert(strSql);
                                    con2.close();
                                    System.out.println("Line209");
                                    //向context中压值
                                    context.setValue("group",group);
                                    context.setValue("tie",tie);
                                }
                                rs1.close();
                                con.close();
                            }
                            catch(Exception esql){
                                System.out.println("in LoginComponent.getComponentData(),catch SQLException.");
                                System.out.println(esql);
                            }

请问这是什么原因？

too many connections to database//连接数太多
java.lang.NullPointerException//有空指针错误

读了你的程序，sqlbean的实例有 con、con1、con2

而在finally中关闭的仅con

也就是说，当空指针例外抛出时，有可能con1、con2的连接并没有正确关闭.