trim()后报异常,好像不是这个原因 警告: Unhandled Exception thrown: class java.lang.NullPointerExceptionStandardWrapperValve[action]: Servlet.service() for servlet action threw exceptionjava.lang.NullPointerExceptionjava.lang.NullPointerException at mylogin.MyAction.yanzhen(MyAction.java:36) at mylogin.MyAction.execute(MyAction.java:21)
先把myActionForm.getId(),myActionForm.getPassword() 用System.out.println(myActionForm.getId()); 用System.out.println(myActionForm.getPassword()); 打印出来看看有不有结果.以确实是不是界面没有获取到数据再把myActionForm.getId()和myActionForm.getPassword(). 同理打印,以确定是不是数据库里获取的值错了.SQL语句写错了: 原: String sql="select * from liuyanban where id='"+s+"' and passwod='"+t+"'" 改: String sql = "select * from liuyanban where id='"+s+"' "+"and password='"+t+"'"; 还有最好是使用PreparedStatement 来传递参数 你试试看可以了不?
警告: Unhandled Exception thrown: class java.lang.NullPointerExceptionStandardWrapperValve[action]: Servlet.service() for servlet action threw exceptionjava.lang.NullPointerExceptionjava.lang.NullPointerException at mylogin.MyAction.yanzhen(MyAction.java:36) at mylogin.MyAction.execute(MyAction.java:21)
用System.out.println(myActionForm.getId());
用System.out.println(myActionForm.getPassword());
打印出来看看有不有结果.以确实是不是界面没有获取到数据再把myActionForm.getId()和myActionForm.getPassword().
同理打印,以确定是不是数据库里获取的值错了.SQL语句写错了:
原: String sql="select * from liuyanban where id='"+s+"' and passwod='"+t+"'"
改: String sql = "select * from liuyanban where id='"+s+"' "+"and password='"+t+"'";
还有最好是使用PreparedStatement 来传递参数
你试试看可以了不?