Question

严重: Servlet.service() for servlet UserServlet threw exception

java.lang.NumberFormatException: null
at java.lang.Integer.parseInt(Integer.java:415)
at java.lang.Integer.parseInt(Integer.java:497)
at servlet.UserServlet.doPost(UserServlet.java:29)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:859)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:574)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1527)
at java.lang.Thread.run(Thread.java:619)
拜托

Answer 1

UserServlet.java:29
在你的UserServlet.java程序的29行（doPost方法），你format了一个空值，可能前台传值没过来吧

追问

那怎么办

追答

如果你熟练使用eclipse的话，可以debug看看传过来了一些什么参数
不行的话，System.out.println看看相关变量呗，又没你源码，也说不上什么

追问

试试吧，谢了

追答

这种情况，一般是前台传参数的时候，参数名写错了，比如acad写成accd什么的造成的

Answer 2

(UserServlet.java:29)
单这样看是，servlet中getP取值中为有一个null，而转变不了Integer类型所以报错