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我们目前正在增强Spring MVC 中现有的Web 应用程序（我只是在学习框架）。我尝试将另一个属性添加到正在推送到数据库中的对象（我也添加了相应的列），但我不断收到NullValueInNestedPathException错误消息。

我已经尝试过谷歌，建议如下：

1) 显式声明新属性的构造函数（已尝试，未解决）
2) 确保实例化新对象（已尝试，未解决）
3) 仔细检查属性的 getter/setter（它们是好的，不是错误）
4）创建一个serialVersionUID（不！）
5）使用调试功能（我做了，我发现该属性为空）

请帮忙！TT 以下是代码：

新物业的VO：

public class ShiftAssignmentLookupVO implements Serializable{

    ...
    public ShiftAssignmentLookupVO(){}

    public String getShiftAssignmentStringValue(){
     return shiftAssignmentStringValue;
    }
    public void setShiftAssignmentStringValue(String shiftAssignmentStringValue){
     this.shiftAssignmentStringValue = shiftAssignmentStringValue;
    }
    ...
}

包含属性的对象的VO：

public class EmployeeCalendarVO implements Serializable {
    ...
    //the new property:
    private ShiftAssignmentLookupVO shiftAssignmentVO = new ShiftAssignmentLookupVO();

    public void setShiftAssignmentVO(ShiftAssignmentLookupVO shiftAssignmentVO){
      this.shiftAssignmentVO = shiftAssignmentVO;
    }
    public ShiftAssignmentLookupVO getShiftAssignmentVO(){
      return shiftAssignmentVO;
    }
    ...
}

这是休眠映射：

<class name = "EmployeeCalendarVO" table = "EMP_WRK_CDR">
    ...
    <many-to-one name = "shiftAssignmentVO" lazy = "false">
        <column name = "ID_ASSIGNMENT" />
    </many-to-one>
    ...
</class>

我尝试访问该属性的jsp：

<spring:bind path = "employeecalendar.empCalList[${ecl.index}].shiftAssignmentVO.shiftAssignmentID">
   ...
</spring:bind>

最后（哇！）堆栈跟踪：

Aug 8, 2013 10:36:18 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet dtr threw exception
org.springframework.beans.NullValueInNestedPathException: Invalid property     'empCalList[0].shiftAssignmentVO' of bean class     [com.safeway.dtr.employee.vo.EmpCalManager]: Value of nested property     'empCalList[0].shiftAssignmentVO' is null
    at org.springframework.beans.BeanWrapperImpl.getNestedBeanWrapper(BeanWrapperImpl.java:443)
    at org.springframework.beans.BeanWrapperImpl.getBeanWrapperForPropertyPath(BeanWrapperImpl.java:418)
    at org.springframework.beans.BeanWrapperImpl.getBeanWrapperForPropertyPath(BeanWrapperImpl.java:419)
    at org.springframework.beans.BeanWrapperImpl.getPropertyValue(BeanWrapperImpl.java:524)
    at org.springframework.validation.AbstractPropertyBindingResult.getActualFieldValue(AbstractPropertyBindingResult.java:78)
    at org.springframework.validation.AbstractBindingResult.getFieldValue(AbstractBindingResult.java:337)
    at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:119)
at org.springframework.web.servlet.tags.BindTag.doStartTagInternal(BindTag.java:116)
    at org.springframework.web.servlet.tags.RequestContextAwareTag.doStartTag(RequestContextAwareTag.java:77)
    at org.apache.jsp.WEB_002dINF.jsp.employee.employeecalendar_jsp._jspService(employeecalendar_jsp.java:1184)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
    at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:551)
    at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:488)
    at org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:968)
    at org.apache.jasper.runtime.PageContextImpl.include(PageContextImpl.java:624)
    at org.apache.struts.tiles.TilesUtilImpl.doInclude(TilesUtilImpl.java:135)
    at org.apache.struts.tiles.TilesUtil.doInclude(TilesUtil.java:149)
    at org.apache.struts.tiles.taglib.InsertTag.doInclude(InsertTag.java:761)
    at org.apache.struts.tiles.taglib.InsertTag$InsertHandler.doEndTag(InsertTag.java:893)
    at org.apache.struts.tiles.taglib.InsertTag.doEndTag(InsertTag.java:462)
    at org.apache.jsp.WEB_002dINF.jsp.defaultLayout_jsp._jspx_meth_tiles_005finsert_005f1(defaultLayout_jsp.java:286)
    at org.apache.jsp.WEB_002dINF.jsp.defaultLayout_jsp._jspService(defaultLayout_jsp.java:115)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
    at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:145)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:251)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1144)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:880)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:793)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:476)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:431)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    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:127)
    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.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Thread.java:595)

嗨 drurenia，这是根据要求提供的 empCalManager：

public class EmpCalManager {  
    ...
    private List<EmployeeCalendarVO> empCalList = LazyList.decorate(new ArrayList<EmployeeCalendarVO>(),FactoryUtils.instantiateFactory(EmployeeCalendarVO.class));
    public List<EmployeeCalendarVO> getEmpCalList() {
        return empCalList;
    }
    public void setEmpCalList(List<EmployeeCalendarVO> empCalList) {
        this.empCalList = empCalList;
    }
    ...
}

这件作品从桌子上拉下来：

public List<EmployeeCalendarVO> getEmployeeWorkCalendar(int empId, Date from, Date to){
    Session session = sessionFactory.getCurrentSession();
    session.flush();
    Query query = session.createQuery(" from EmployeeCalendarVO as empWrkCdr where " +
            "empWrkCdr.employeeId = ? AND empWrkCdr.workDate between ? AND ? order by empWrkCdr.workDate");

    query.setInteger(0, empId);

    query.setDate(1, from);
    query.setDate(2, to);

    return query.list();
}

有任何想法吗？建议？感谢任何会提供帮助的人！
*PS 如果这篇文章中缺少某些代码/部分代码，请通知我，以便我发布它们。

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1 回答 1

0

我发现出了什么问题：似乎我将新属性的列的默认值设置为null！我希望其他遇到同样错误的人尝试这个解决方案。-__-！感谢您的drurenia兴趣！:D

于 2013-08-08T07:05:14.820 回答