执行列表查询(Subarea)打印的SQL语句:
Hibernate:
select
region0_.id as id1_1_,
region0_.province as province2_1_,
region0_.city as city3_1_,
region0_.district as district4_1_,
region0_.postcode as postcode5_1_,
region0_.shortcode as shortcod6_1_,
region0_.citycode as citycode7_1_
from
bc_region region0_
Hibernate:
select
count(*) as y0_
from
bc_subarea this_
Hibernate:
select
this_.id as id1_3_0_,
this_.decidedzone_id as decidedz2_3_0_,
this_.region_id as region_i3_3_0_,
this_.addresskey as addressk4_3_0_,
this_.startnum as startnum5_3_0_,
this_.endnum as endnum6_3_0_,
this_.single as single7_3_0_,
this_.position as position8_3_0_
from
bc_subarea this_ limit ?
Hibernate:
select
region0_.id as id1_1_0_,
region0_.province as province2_1_0_,
region0_.city as city3_1_0_,
region0_.district as district4_1_0_,
region0_.postcode as postcode5_1_0_,
region0_.shortcode as shortcod6_1_0_,
region0_.citycode as citycode7_1_0_
from
bc_region region0_
where
region0_.id=?
控制台打印出来了4条SQL语句,其中查询了两次Region类对应的表,可能是错误所指的循环。
Region类和Subarea类是一对多的关系,两个类属性如下图:
错误信息:
22:20:56,738 INFO JSONObject:769 - Property 'autoClear' of class org.hibernate.internal.SessionImpl has no read method. SKIPPED
22:20:59,961 ERROR DefaultDispatcherErrorHandler:42 -
Exception occurred during processing request: There is a cycle in the hierarchy!
net.sf.json.JSONException: There is a cycle in the hierarchy!
at net.sf.json.util.CycleDetectionStrategy$StrictCycleDetectionStrategy.handleRepeatedReferenceAsObject(CycleDetectionStrategy.java:97)
at net.sf.json.JSONObject._fromBean(JSONObject.java:657)
at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:765)
at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
at net.sf.json.JSONArray._processValue(JSONArray.java:2513)
at net.sf.json.JSONArray.processValue(JSONArray.java:2538)
at net.sf.json.JSONArray.addValue(JSONArray.java:2525)
at net.sf.json.JSONArray._fromCollection(JSONArray.java:1056)
at net.sf.json.JSONArray.fromObject(JSONArray.java:123)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:240)
at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:765)
at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
at net.sf.json.JSONObject._fromMap(JSONObject.java:1168)
at net.sf.json.JSONObject.fromObject(JSONObject.java:163)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:765)
at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:765)
at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:765)
at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:765)
at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:765)
at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
at net.sf.json.JSONArray._processValue(JSONArray.java:2513)
at net.sf.json.JSONArray.processValue(JSONArray.java:2538)
at net.sf.json.JSONArray.addValue(JSONArray.java:2525)
at net.sf.json.JSONArray._fromCollection(JSONArray.java:1056)
at net.sf.json.JSONArray.fromObject(JSONArray.java:123)
at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:240)
at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:765)
at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
at com.dengtuzi.bos.web.action.base.BaseAction.object2Json(BaseAction.java:67)
at com.dengtuzi.bos.web.action.SubareaAction.pageQuery(SubareaAction.java:69)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:891)
at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1293)
at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)
at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117)
at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108)
at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369)
at ognl.ASTMethod.getValueBody(ASTMethod.java:90)
at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
at ognl.SimpleNode.getValue(SimpleNode.java:258)
at ognl.Ognl.getValue(Ognl.java:494)
at ognl.Ognl.getValue(Ognl.java:458)
at com.opensymphony.xwork2.ognl.OgnlUtil$2.execute(OgnlUtil.java:309)
at com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecute(OgnlUtil.java:340)
at com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:307)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:423)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:287)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:250)
at org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at com.dengtuzi.bos.web.interceptor.BOSLoginIntercepter.doIntercept(BOSLoginIntercepter.java:28)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564)
at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.orm.hibernate5.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:151)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
分析错误信息,发现查询到分区信息后,将数据转成JSON的时候发生。
调用方法代码:
//转json数据写回前端
object2Json(pageBean, new String[]{"currentPage","detachedCriteria","pageSize","subareas","decidedzone"});
object2Json方法:
public void object2Json(Object object,String[] excludes){
//设置忽略字段,将pageBean转为json对象写回给前端
JsonConfig config = new JsonConfig();
config.setExcludes(excludes);
//静态方法转换成json对象
String json = JSONObject.fromObject(object, config).toString();
//设置文本格式
ServletActionContext.getResponse().setContentType("text/json;charset=utf-8");
try {
//将数据返回给前端
ServletActionContext.getResponse().getWriter().println(json);
} catch (IOException e) {
e.printStackTrace();
}
}
在调用object2Json方法处下断点,开始调试。发现pageBean中Rows中Region的值是代理对象,根据Hibernate默认的延迟加载机制,Subarea关联的Region属性在查询时并没有真正获取Region对象的数据,只有在Region对象的数据使用时(执行object2Json方法时)才真正从数据库中加载它的数据。
展开region发现下面有一个名为handler的值,这个属性值并不属于定义的Region实体类,看值的名字应该是Hibernate用来实现延迟加载的,继续展开可以看到handler下面还有很多与Region实体类不相关的属性。各种矛头指向延迟加载...
为了验证是否关联的Region对象数据的延迟加载导致的异常,在转JSON数据时把region设置为忽略的字段,然后重新调试。
object2Json(pageBean, new String[]{"region","currentPage","detachedCriteria","pageSize","subareas","decidedzone"});
这时程序已经正常运行,控制台打印的SQL语句变为3条:
Hibernate:
select
region0_.id as id1_1_,
region0_.province as province2_1_,
region0_.city as city3_1_,
region0_.district as district4_1_,
region0_.postcode as postcode5_1_,
region0_.shortcode as shortcod6_1_,
region0_.citycode as citycode7_1_
from
bc_region region0_
Hibernate:
select
count(*) as y0_
from
bc_subarea this_
Hibernate:
select
this_.id as id1_3_0_,
this_.decidedzone_id as decidedz2_3_0_,
this_.region_id as region_i3_3_0_,
this_.addresskey as addressk4_3_0_,
this_.startnum as startnum5_3_0_,
this_.endnum as endnum6_3_0_,
this_.single as single7_3_0_,
this_.position as position8_3_0_
from
bc_subarea this_ limit ?
既然是Subarea单向关联关联的Region类延迟加载导致的问题,那问题就很好解决了,在Subarea的映射文件中,名为"region"的多对一(many-to-one)标签中设置关闭延迟加载(lazy="false"),问题解决。
<many-to-one lazy="false" name="region" class="Region" >
<column name="region_id" length="32" />
</many-to-one>