从网上down了一个jsp的源码,安装之后想要点击servlet的链接,出现如下错误!
servlet的配置应该没有问题,是这样配的<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>PageSearchServlet</servlet-name>
<servlet-class>com.lovo.cq.shopping10_1.servlet.PageSearchServlet</servlet-class>
</servlet><servlet-mapping>
<servlet-name>PageSearchServlet</servlet-name>
<url-pattern>/pageSearchServlet</url-pattern>
</servlet-mapping>请求:
<form action="pageSearchServlet" method="post" id="searchForm">
。
</form>出现如下错误:HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception java.lang.NullPointerException
com.lovo.cq.shopping10_1.daoimpl.BookDaoImpl.searchBooks(BookDaoImpl.java:267)
com.lovo.cq.shopping10_1.daoimpl.BookDaoImpl.doPage(BookDaoImpl.java:294)
com.lovo.cq.shopping10_1.model.Model.doPage(Model.java:131)
com.lovo.cq.shopping10_1.servlet.PageSearchServlet.doGet(PageSearchServlet.java:38)
com.lovo.cq.shopping10_1.servlet.PageSearchServlet.doPost(PageSearchServlet.java:49)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.lovo.cq.shopping10_1.filter.UnicodeFilter.doFilter(UnicodeFilter.java:27)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.13 logs.
--------------------------------------------------------------------------------Apache Tomcat/6.0.13
servlet的配置应该没有问题,是这样配的<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>PageSearchServlet</servlet-name>
<servlet-class>com.lovo.cq.shopping10_1.servlet.PageSearchServlet</servlet-class>
</servlet><servlet-mapping>
<servlet-name>PageSearchServlet</servlet-name>
<url-pattern>/pageSearchServlet</url-pattern>
</servlet-mapping>请求:
<form action="pageSearchServlet" method="post" id="searchForm">
。
</form>出现如下错误:HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception java.lang.NullPointerException
com.lovo.cq.shopping10_1.daoimpl.BookDaoImpl.searchBooks(BookDaoImpl.java:267)
com.lovo.cq.shopping10_1.daoimpl.BookDaoImpl.doPage(BookDaoImpl.java:294)
com.lovo.cq.shopping10_1.model.Model.doPage(Model.java:131)
com.lovo.cq.shopping10_1.servlet.PageSearchServlet.doGet(PageSearchServlet.java:38)
com.lovo.cq.shopping10_1.servlet.PageSearchServlet.doPost(PageSearchServlet.java:49)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.lovo.cq.shopping10_1.filter.UnicodeFilter.doFilter(UnicodeFilter.java:27)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.13 logs.
--------------------------------------------------------------------------------Apache Tomcat/6.0.13
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空指针错误
一步一步的检查值是否传过来。
希望对你有帮助
估计是没有注入进来
java.lang.NullPointerException
com.lovo.cq.shopping10_1.daoimpl.BookDaoImpl.searchBooks(BookDaoImpl.java:267)可以看出,是BookDaoImpl.java文件里的searchBooks方法里抛出来了空指针。从方法名可以猜测,这个方法应该是连接了数据库取数据,那么很可能是数据库没有准备好而造成的。