求解

[阿使]

2019-6-14 12:34:17 org.apache.catalina.core.ApplicationDispatcher invoke 严重: Servlet.service() for servlet jsp threw exception java.lang.NullPointerException at org.apache.jsp.user.page.detail_jsp._jspService(detail_jsp.java:128) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334) at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:411) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338) at tedu.cn.servlet.DetailBookServlet.doGet(DetailBookServlet.java:27) at javax.servlet.http.HttpServlet.service(HttpServlet.java:620) at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve

[a_b_a_b_a_b_a_b]

初步判断book为空，是否没有给book赋值？

[对梦想的牵挂]

你的book.getTitle()没有获取到值，报了空指针。查看写的返回到页面的方法有没有这个值

[阿使]

我book设为空了，刚改好了，谢谢

[CS_草祭先生]

detail.jsp 60行代码，book为空，查看返回值是否有问题。