spring +springmvc+mybatis，service中调用dao接口报空

搭建ssm，启动项目没问题，但是在service实现类中调用dao接口时，对象loginDao对象是空的，错误信息如下

log4j:ERROR Error occured while converting date.
java.lang.NullPointerException
at java.lang.System.arraycopy(Native Method)
at java.lang.AbstractStringBuilder.getChars(Unknown Source)
at java.lang.StringBuffer.getChars(Unknown Source)
at org.apache.log4j.helpers.ISO8601DateFormat.format(ISO8601DateFormat.java:130)
at java.text.DateFormat.format(Unknown Source)
at org.apache.log4j.helpers.PatternParser$DatePatternConverter.convert(PatternParser.java:443)
at org.apache.log4j.helpers.PatternConverter.format(PatternConverter.java:65)
at org.apache.log4j.PatternLayout.format(PatternLayout.java:506)
at org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:310)
at org.apache.log4j.WriterAppender.append(WriterAppender.java:162)
at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251)
at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66)
at org.apache.log4j.Category.callAppenders(Category.java:206)
at org.apache.log4j.Category.forcedLog(Category.java:391)
at org.apache.log4j.Category.log(Category.java:856)
at org.apache.commons.logging.impl.Log4JLogger.debug(Log4JLogger.java:177)
at org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:132)
at org.springframework.web.servlet.DispatcherServlet.processHandlerException(DispatcherServlet.java:1148)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:985)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:939)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:917)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:824)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:643)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:798)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
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.Http11Processor.process(Http11Processor.java:861)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:620)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)

这是控制台报的错误信息，指向的就是service实现类中调用dao接口的方法

2015-12-27 18:28:40,374 [http-8080-2] DEBUG org.springframework.web.servlet.DispatcherServlet - Could not complete request
java.lang.NullPointerException
at com.zj.service.impl.LoginServiceImpl.find(LoginServiceImpl.java:27)
at com.zj.controller.LoginController.testLogin2(LoginController.java:45)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:440)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:428)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:917)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:824)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:643)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:798)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
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.Http11Processor.process(Http11Processor.java:861)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:620)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)

http://ask.csdn.net/questions/228070
这个地址可以看见其他配置文件的内容

建议楼主逐层向下排查，看一下在哪个位置没有获取到id的值

估计配置文件的问题。发个看看

估计配置文件的问题。发个看看

楼主你的service中的dao是通过配置文件注入的么。。看你贴的图里没有@autowired啊。。

你要是用注解方式注入，那就是缺少@autowired，如果是通过xml配置文件配置，那就贴下配置文件~~~~

loginDao要用注解赋值。

看你的spring配置文件中使用了注解注入的方式，但是在service中loginDao对象没有加上自动注入的注解即@Autowired