The server encountered an internal error () that prevented it from fulfilling this request.

Question

HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: An exception occurred processing JSP page /ShowArticleDetail.jsp at line 7
4:
5: <%
6: String ID = request.getParameter("id");
7: int id = Integer.parseInt(ID);
8:
9: Class.forName("com.mysql.jdbc.Driver");
10: String url = "jdbc:mysql://localhost/bbs?user=root&password=";
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause
java.lang.NumberFormatException: null
java.lang.Integer.parseInt(Integer.java:415)
java.lang.Integer.parseInt(Integer.java:497)
org.apache.jsp.ShowArticleDetail_jsp._jspService(ShowArticleDetail_jsp.java:60)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.18 logs.

Apache Tomcat/6.0.18

哪位高手帮忙看下哪里出错了，mysql已经连接上去了，ShowArticleTree页面可以显示,但点击链接的时候出现上面的异常。

Answer 1

6: String ID = request.getParameter("id");
7: int id = Integer.parseInt(ID);
是这句报错了
你获取的ID可能是null
把他转发为 整形（int）就会报错

Answer 2

肯定是ID为null或者不是数字类型的字符串，检查 request.getParameter("id"); 返回的值