为什么 上面那段 代码 当用户名 错误的时候 不是输出 我指定的 错误 而是 系统报错::::type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:372) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236) javax.servlet.http.HttpServlet.service(HttpServlet.java:802) root cause java.lang.NullPointerException org.apache.jsp.news.passinfo_jsp._jspService(passinfo_jsp.java:97) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94) javax.servlet.http.HttpServlet.service(HttpServlet.java:802) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236) javax.servlet.http.HttpServlet.service(HttpServlet.java:802) note The full stack trace of the root cause is available in the Apache Tomcat/5.0.29 logs.
你没截取异常 没看到有try catch
初始化一下就可以了啊,虽然可以输出但是也有可能出现空值的情况,提示不是说了吗“有可能出现空值”啊!variable pass might not have been initial
String name=null;
String sql=null;
try
{
.....}catch(Exception e)
{}
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:372)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause java.lang.NullPointerException
org.apache.jsp.news.passinfo_jsp._jspService(passinfo_jsp.java:97)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.29 logs.
没看到有try catch