实际开发常见错误

实际开发常见错误

1、  绑定错了对象导致attempted to delete null:

现象:在页面中删除对象失败

原因:在DAO的remove方法中

public void reomveSight(Long[] sightid) throws SightException

{

      for(int i=0;i<sightid.length;i++)

       super.removeObject(TtourInfo***.class,sightid[i]);

}

绑定错了对象,导致attempted to delete null错误。



2、  在一对多的前提下删除的时候不能级联删除子表中的数据:

现象:删除的时候不能级联删除子表中的数据导致报外键引用的错误。

解决方法:sight景点与image图片是一对多的关系，sight的hbm.xml配置文件原来在配置图片时是：

<!-- bi-directional one-to-many association to TtourInfoImage -->

    <set

        name="ttourInfoImages"

        lazy="true"

        inverse="true"

        cascade="none"

    >

        <meta attribute="field-description">

           @hibernate.set

            lazy="true"

            inverse="true"

            cascade="none"

           @hibernate.collection-key

            column="COMPANY"

           @hibernate.collection-one-to-many

            class="com.strongit.tour.bo.TtourInfoImage"

        </meta>

        <key>

            <column name="SIGHTID" />

        </key>

        <one-to-many

            class="com.strongit.tour.bo.TtourInfoImage"

        />

    </set>

现在改成

<!-- bi-directional one-to-many association to TtourInfoImage -->

    <set

        name="ttourInfoImages"

        lazy="true"

        inverse="true"

        cascade="all"

    >

        <meta attribute="field-description">

           @hibernate.set

            lazy="true"

            inverse="true"

            cascade="all"

           @hibernate.collection-key

            column="COMPANY"

           @hibernate.collection-one-to-many

            class="com.strongit.tour.bo.TtourInfoImage"

        </meta>

        <key>

            <column name="SIGHTID" />

        </key>

        <one-to-many

            class="com.strongit.tour.bo.TtourInfoImage"

        />

    </set>

就可以了。



3、  景区dao配置文件错误

错误描述：

Error registering

bean with name

'tour.scenicArea.sceneryAreaDao'

defined in ServletContext resource

[/WEB-INF/config_ext/applicationContext-tour-sceneryarea-dao.xml]:

Bean class

[import com.strongit.tour.scenicArea.dao.impl.SceneryAreaDaoImpl]

not found;

nested exception is java.lang.ClassNotFoundException:

import com.strongit.tour.scenicArea.dao.impl.SceneryAreaDaoImpl

解决方法:

applicationContext-tour-sceneryarea-dao.xml   中

class="com.strongit.tour.scenicArea.dao.impl.SceneryAreaDaoImpl"

写成了

class="import com.strongit.tour.scenicArea.dao.impl.SceneryAreaDaoImpl"



4、  景点配置文件错误

org.springframework.beans.factory.BeanCreationException:

Error creating bean with name

'tour.service.isightService'

defined in ServletContext resource

[/WEB-INF/config_ext/applicationContext-tour-sight-service.xml]:

Can't resolve reference to bean

'tour.service.sightService'

while setting property 'target';

nested exception is org.springframework.beans.factory.BeanCreationException:

Error creating bean with name 'tour.service.sightService'

defined in ServletContext resource [/WEB-INF/config_ext/applicationContext-tour-sight-service.xml]:

Error setting property values; nested exception is org.springframework.beans.NotWritablePropertyException:

Invalid property 'sightDao' of bean class [com.strongit.tour.scenicArea.service.impl.SightServiceImpl]:

Bean property 'sightDao' is not writable or has an invalid setter method:

Does the parameter type of the setter match the return type of the getter?

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'tour.service.sightService' defined in ServletContext resource [/WEB-INF/config_ext/applicationContext-tour-sight-service.xml]: Error setting property values; nested exception is org.springframework.beans.NotWritablePropertyException: Invalid property 'sightDao' of bean class [com.strongit.tour.scenicArea.service.impl.SightServiceImpl]: Bean property 'sightDao' is not writable or has an invalid setter method: Does the parameter type of the setter match the return type of the getter?

org.springframework.beans.NotWritablePropertyException: Invalid property 'sightDao' of bean class [com.strongit.tour.scenicArea.service.impl.SightServiceImpl]: Bean property 'sightDao' is not writable or has an invalid setter method: Does the parameter type of the setter match the return type of the getter?

错误原因:

在com.strongit.tour.scenicArea.service.impl.SightServiceImpl类中没有对sightDao添加set属性。



5、  修改时没有提交值

缺少<html:hidden property="sceneryareaid"></html:hidden>来绑定id的值。



6、  初始化景点信息出错

org.apache.jasper.JasperException:

/member/tour/sceneryareamanage/sight_edit.jsp(121,7)

According to the TLD attribute property is mandatory for tag text

错误原因：htmltext标记与input标记的属性混用



7、  删除景点报500错

javax.servlet.ServletException:

No bean named '/tour/scenicArea/deleteSightAction' is defined:

错误原因：

在applicationcontext-tour-sight-action中删除的action配置的path

与struts-config-tour-sight中相应的删除配置不相同



8、  加载FORM表单的上传的文件数组元素时报参数错误

错误提示：

IllegalArgumentException          --argument type mismatch

解决方法：

在<html:form中加入enctype="multipart/form-data"



9、  使用HQL语句时出错

景点与图片是一对多的关系,现在要从一的景点中找到相应的图片的所有信息。

在daoimpl中



public List querySQLEx(String SqlStr) throws SightException

{

      return super.getHibernateTemplate().find(SqlStr);

}



public TtourInfoImage getImagePathToSight(Long sightid) throws SightException

{

  return (TtourInfoImage) this.querySQLEx("select TtourInfoImage m where m.ttourInfoSight.sightid="+sightid);

}

在删除的action的调用中

String msg="";

  try

  {

   String [] sightid=request.getParameter("delid").split(",");

   try

   {

    String root = getServletContext().getRealPath("/");

    System.out.println(root);

    Long [] sightID=new Long[sightid.length];

    List fileList=new ArrayList();

    for(int i=0;i<sightid.length;i++)

    {

     sightID[i]=Long.valueOf(sightid[i].trim());

     //把图片对象放入临时保存图片的图片路径数组中

fileList.add(sightService.getImagePathToSight(sightID[i]).getImageFile());

     System.out.println("原图="+sightService.getImagePathToSight(sightID[i]).getImageFile());

     fileList.add(sightService.getImagePathToSight(sightID[i]).getImageBreviry());

     System.out.println("缩略图="+sightService.getImagePathToSight(sightID[i]).getImageBreviry());

    }

    sightService.reomveSight(sightID);//先批量删除景点和与景点有关的图片表的数据

    sightService.delImage(root,fileList);//再删除图片表中，与景点相关的图片

    msg = "景点删除成功!";

   }

   catch (Exception e)

   {

    System.out.println(e.getMessage());

    log.info(e.getMessage());

    msg = "对不起,在您删除的数据中已有数据被使用,无法删除！";

   }

  }

  catch (RuntimeException e)

  {

   e.printStackTrace();

   msg="在删除景点的过程中出现意外错误!";

  }

  request.setAttribute("msg", msg);

     return mapping.findForward("success");



10、  配置文件错误

nested exception is org.springframework.beans.factory.BeanCreationException:

Error creating bean with name 'tour.service.commodityService' defined in ServletContext resource

[/WEB-INF/config_user/applicationContext-tour-commodity-service.xml]:

Error setting property values;

nested exception is org.springframework.beans.PropertyAccessExceptionsException:

PropertyAccessExceptionsException (1 errors);

nested propertyAccessExceptions are:

[org.springframework.beans.TypeMismatchException:

Failed to convert property value of type

[com.strongit.tour.commodityManage.dao.impl.CommodityTypeDAOImpl]

to required type [com.strongit.tour.commodityManage.dao.ICommodityDAO]

for property 'commodityDAO']

org.springframework.beans.factory.BeanCreationException:

Error creating bean with name 'tour.service.commodityService'

defined in ServletContext resource

[/WEB-INF/config_user/applicationContext-tour-commodity-service.xml]:

Error setting property values;

nested exception is org.springframework.beans.PropertyAccessExceptionsException:

PropertyAccessExceptionsException (1 errors); nested propertyAccessExceptions are:

[org.springframework.beans.TypeMismatchException:

Failed to convert property value of type [com.strongit.tour.commodityManage.dao.impl.CommodityTypeDAOImpl]

to required type [com.strongit.tour.commodityManage.dao.ICommodityDAO]

for property 'commodityDAO']

PropertyAccessExceptionsException (1 errors)

org.springframework.beans.TypeMismatchException:

Failed to convert property value of type

[com.strongit.tour.commodityManage.dao.impl.CommodityTypeDAOImpl]

to required type [com.strongit.tour.commodityManage.dao.ICommodityDAO]

for property 'commodityDAO'

错误原因:

在dao配置文件中 class="com.strongit.tour.commodityManage.dao.impl.CommodityDAOImpl"

写成了class="com.strongit.tour.commodityManage.dao.impl.CommodityTypeDAOImpl"



11、  级联删除商品的相关图片时报错

将商品hbm.xml文件中图片的相关链接的cascode="none"改为"all"。



12、  添加商品时没有触发action

在<html:form>里的action写错了。



13、  添加商品时没有找到actoin

javax.servlet.ServletException:

Error creating bean with name

'/tour/commodityManage/addCommodityAction'

defined in ServletContext resource

[/WEB-INF/config_user/applicationContext-tour-commodity-action.xml]:

Error setting property values;

nested exception is org.springframework.beans.NotWritablePropertyException:

Invalid property 'commodityService' of bean class

[com.strongit.tour.commodityManage.action.AddCommodityAction]:

Bean property 'commodityService' is not writable or has an invalid setter method:

Does the parameter type of the setter match the return type of the getter?

在AddCommodityAction.do中少了commodityService的set方法

14、  加载工程时有绔绞欢之类的错误

现象:加载工程时有绔绞欢之类的字样的错误,工程不能启动

解决方法:选中工程,选菜单下的Project下的Properties选项,

把字符编码改为UTF-8。

15、  工程中出现没有编译成的class文件

工程中出现没有编译成class文件时,选eclipe里的project的BuildAutomatically就行。