Jsonexception:there is a cycle in the hierarchy solution

This problem is easy to use with Hibernate, mainly due to the cascading relationship of Pojo class attributes. For example, employees and departments, which have departmental attributes in the employee table, and a collection of employees in the departmental table, will throw this exception if there is a problem with nested references.

The workaround is simple, when you convert each object to a JSON object, use the Setexcludes function to remove the cascading properties, as follows:

Get all Departments    //Return JSON object string public string    getalldep () {        list list = Deptdao.findall ();        Jsonconfig config = new Jsonconfig ();        Config.setexcludes (New string[]{"Emps"});//Remove the Emps attribute        String json = jsonarray.fromobject (list, config). toString () ;        return JSON;    }        Get all employees public    String getallemp (int id) {        list list = Empdao.findbyproperty ("Dept.deptid", id);        Jsonconfig config = new Jsonconfig ();        Config.setexcludes (New string[]{"dept"});//Remove the Dept attribute        String JSON = jsonarray.fromobject (list, config). toString ( );        return JSON;    }

The exception code is as follows:

Severity: Servlet.service () forservlet Springmvc threw Exceptionnet.sf.json.JSONException:There is a cycle in the hierarchy!At Net.sf.json.util.cycledetectionstrategy$strictcycledetectionstrategy.handlerepeatedreferenceasobject ( Cycledetectionstrategy.java:97) at Net.sf.json.jsonobject._frombean (Jsonobject.java:857) at Net.sf.json.JSONObject.fromObject (Jsonobject.java:192) at Net.sf.json.jsonobject._processvalue (Jsonobject.java:2774) at Net.sf.json.jsonobject._setinternal (Jsonobject.java:2798) at Net.sf.json.JSONObject.setValue (Jsonobject.java:1507) at Net.sf.json.jsonobject._frombean (Jsonobject.java:940) at Net.sf.json.JSONObject.fromObject (Jsonobject.java:192) at Net.sf.json.jsonarray._processvalue (Jsonarray.java:2557) at Net.sf.json.JSONArray.processValue (Jsonarray.java:2588) at Net.sf.json.JSONArray.addValue (Jsonarray.java:2575) at Net.sf.json.jsonarray._fromcollection (Jsonarray.java:1082) at Net.sf.json.JSONArray.fromObject (Jsonarray.java:145) at Net.sf.json.jsonobject._processvalue (Jsonobject.java:2749) at Net.sf.json.jsonobject._setinternal (Jsonobject.java:2798) at Net.sf.json.JSONObject.setValue (Jsonobject.java:1507) at Net.sf.json.jsonobject._frombean (Jsonobject.java:940) at Net.sf.json.JSONObject.fromObject (Jsonobject.java:192) at Net.sf.json.jsonarray._processvalue (Jsonarray.java:2557) at Net.sf.json.JSONArray.processValue (Jsonarray.java:2588) at Net.sf.json.JSONArray.addValue (Jsonarray.java:2575) at Net.sf.json.jsonarray._fromcollection (Jsonarray.java:1082) at Net.sf.json.JSONArray.fromObject (Jsonarray.java:145) at Com.service.EmpService.getAllDep (Empservice.java:31) at com.service.empservice$ $FastClassByCGLIB $ $fef 4bb53.invoke (<generated>) at Net.sf.cglib.proxy.MethodProxy.invoke (Methodproxy.java:149) at Org.springframework.aop.framework.cglib2aopproxy$cglibmethodinvocation.invokejoinpoint ( Cglib2aopproxy.java:700) at Org.springframework.aop.framework.ReflectiveMethodInvocation.proceed (Reflectivemethodinvocation.java: 149) at Org.springframework.transaction.interceptor.TransactionInterceptor.invoke (Transactioninterceptor.java: 106) at Org.springframework.aop.framework.ReflectiveMethodInvocation.proceed (Reflectivemethodinvocation.java: 171) at Org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke (Exposeinvocationinterceptor.java :89) at Org.springframework.aop.framework.ReflectiveMethodInvocation.proceed (Reflectivemethodinvocation.java: 171) at Org.springframework.aop.framework.cglib2aopproxy$dynamicadvisedinterceptor.intercept ( Cglib2aopproxy.java:635) at com.service.empservice$ $EnhancerByCGLIB $$8FCE1D77.GETALLDEP (<generated>) at Com.action.DepAction.getAllDept (Depaction.java:22) 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:40s) at Org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doInvokeMethod ( Handlermethodinvoker.java:413) at Org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod ( Handlermethodinvoker.java:134) at Org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod ( Annotationmethodhandleradapter.java:310) at Org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle ( Annotationmethodhandleradapter.java:297) at Org.springframework.web.servlet.DispatcherServlet.doDispatch (Dispatcherservlet.java:875) at Org.springframework.web.servlet.DispatcherServlet.doService (Dispatcherservlet.java:809) at Org.springframework.web.servlet.FrameworkServlet.processRequest (Frameworkservlet.java:571) at Org.springframework.web.servlet.FrameworkServlet.doGet (Frameworkservlet.java:30w) at Javax.servlet.http.HttpServlet.service (Httpservlet.java:690) at Javax.servlet.http.HttpServlet.service (Httpservlet.java:803) at Org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (Applicationfilterchain.java:290) at Org.apache.catalina.core.ApplicationFilterChain.doFilter (Applicationfilterchain.java:206) at Org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal ( Opensessioninviewfilter.java:198) at Org.springframework.web.filter.OncePerRequestFilter.doFilter (Onceperrequestfilter.java:76) 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:230) at Org.apache.catalina.core.StandardContextValve.invoke (Standardcontextvalve.java:175) at Org.apache.catalina.core.StandardHostValve.invoke (Standardhostvalve.java:128) at Org.apache.catalina.valves.ErrorReportValve.invoke (Errorreportvalve.java:104) at Org.apache.catalina.core.StandardEngineValve.invoke (Standardenginevalve.java:109) at Org.apache.catalina.connector.CoyoteAdapter.service (Coyoteadapter.java:261) at Org.apache.coyote.http11.Http11Processor.process (Http11processor.java:844) at Org.apache.coyote.http11.http11protocol$http11connectionhandler.process (Http11protocol.java:581) at Org.apache.tomcat.util.net.jioendpoint$worker.run (Jioendpoint.java:447) at Java.lang.Thread.run (Thread.java:722)

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Jsonexception:there is a cycle in the hierarchy solution