java.lang.NullPointerException哪里不对啊

来源：百度知道 编辑：UC知道 时间：2024/05/15 06:35:08
错误提示为:
java.lang.NullPointerException
at org.apache.jsp.add$jsp._jspService(add$jsp.java:66)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:201)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:381)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:473)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
-------------------------------------------------------------
jsp页面代码：
<%
ArrayList units=new ArrayList();
units=ZbiaoBean.getInstance().getUnit();

for(int i=0;i<=units.size();i++){
ArrayList unit=(ArrayList)units.get(i);
if(unit!=null)
{
%>
<input type="checkbox" name="checkbox" va

求救！出现java.lang.NullPointerException问题怎么解决？
悬赏分：10 - 离问题结束还有 6 天 22 小时
提示错误如下：
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
com.MembBean.addUser(MembBean.java:19)
org.apache.jsp.regiester.addmemb_jsp._jspService(addmemb_jsp.java:95)
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)