JAVA对象转化JSON出现死循环问题-白红宇

JAVA对象转化JSON出现死循环问题

阅读量：5325 次

发布时间：2019-06-14

本文共 15806 字，大约阅读时间需要 52 分钟。

主要是解决JSON因Hibernate映射生成的集合的转化出现的死循环问题。

这个方法很重要

1     public String ajaxJsonByObjectDirecdt(Object obj, String[] filterNames){ 2         JsonConfig jsonConfig = new JsonConfig(); 3         jsonConfig.setIgnoreDefaultExcludes(false);     4         jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);    //防止自包含 5          6         if(filterNames != null){ 7             //这里是核心，过滤掉不想使用的属性 8             jsonConfig .setExcludes(filterNames) ; 9         }10         JSONObject jsonObj = JSONObject.fromObject(obj, jsonConfig);11         //ajax()方法主要功能是将数据通过输出流输出到Client12         return ajax(jsonObj.toString(), "text/html");13         14     }

对于参数，String[] filterNames，这个字符串数组中存放的是变量的名字(句柄)，而不是变量的类型。

1     public String getUserLoginInfo(){ 2         User user = (User)getSession().getAttribute(USER); 3                 //要过滤的属性集合 4         String[] filterNames =  5                 new String[]{"role", "operatingHistories", "helpInfoBoards", "replyInfos", 6                 "helpInfos", "credits", "users", "user",   7                 "helpInfoBoard"}; 8          9         return ajaxJsonByObjectDirecdt(user, filterNames);10     }

其中User类含有以下属性：

1 public class User implements java.io.Serializable { 2  3     // Fields 4  5     private String id; 6     private Role role; 7     private String username; 8     private String studentNum; 9     private String address;10     private Integer age;11     private String nickname;12     private String sex;13     private String qq;14     private String phonenumber;15     private String fixedTelephone;16     private String password;17     private Timestamp registerDate;18     private String imgUrl;19     private String email;20     private String question;21     private String answer;22     private Timestamp totalOnlineDate;23     private Set
     
       operatingHistories = new HashSet
      
       (24             0);25     private Set
       
         helpInfoBoards = new HashSet
        
         (0);26     private Set
         
           replyInfos = new HashSet
          
           (0);27 private Set
           
             helpInfos = new HashSet
            
             (0);28 private Set
             
               credits = new HashSet
              
               (0);29 30 31 //more methods. 32 }

两端代码参照下，就知道怎么使用了。

后台异常信息：

1 INFO  com.opensymphony.xwork2.config.ConfigurationManager  2 Detected container provider org.apache.struts2.convention.ClasspathConfigurationProvider@67b0eb2c needs to be reloaded.  Reloading all providers.  3 INFO  com.opensymphony.xwork2.config.ConfigurationManager  4 Detected package provider org.apache.struts2.convention.ClasspathConfigurationProvider@67b0eb2c needs to be reloaded.  Reloading all providers.  5 INFO  com.opensymphony.xwork2.config.ConfigurationManager  6 Detected package provider org.apache.struts2.convention.ClasspathConfigurationProvider@31af5c3 needs to be reloaded.  Reloading all providers.  7 INFO  com.opensymphony.xwork2.config.ConfigurationManager  8 Detected package provider org.apache.struts2.convention.ClasspathPackageProvider@5efcd6cc needs to be reloaded.  Reloading all providers.  9 INFO  com.opensymphony.xwork2.config.providers.XmlConfigurationProvider 10 Parsing configuration file [struts-default.xml] 11 INFO  com.opensymphony.xwork2.config.providers.XmlConfigurationProvider 12 Parsing configuration file [struts-plugin.xml] 13 INFO  com.opensymphony.xwork2.config.providers.XmlConfigurationProvider 14 Parsing configuration file [struts.xml] 15 INFO  com.opensymphony.xwork2.config.impl.DefaultConfiguration 16 Overriding property struts.i18n.reload - old value: false new value: true 17 INFO  com.opensymphony.xwork2.config.impl.DefaultConfiguration 18 Overriding property struts.configuration.xml.reload - old value: false new value: true 19 INFO  org.apache.struts2.config.BeanSelectionProvider 20 Loading global messages from i18n 21 INFO  org.apache.struts2.spring.StrutsSpringObjectFactory 22 Initializing Struts-Spring integration... 23 INFO  com.opensymphony.xwork2.spring.SpringObjectFactory 24 Setting autowire strategy to name 25 INFO  org.apache.struts2.spring.StrutsSpringObjectFactory 26 ... initialized Struts-Spring integration successfully 27 2014-06-03 01:07:12 Test: Reloading class 'student.life.support.platform.action.BaseAction'. 28 hql:from student.life.support.platform.model.User as model where model.username = ? 29 Hibernate:  30     select 31         user0_.id as id62_, 32         user0_.address as address62_, 33         user0_.age as age62_, 34         user0_.answer as answer62_, 35         user0_.email as email62_, 36         user0_.fixed_telephone as fixed6_62_, 37         user0_.img_url as img7_62_, 38         user0_.nickname as nickname62_, 39         user0_.password as password62_, 40         user0_.phonenumber as phonenu10_62_, 41         user0_.qq as qq62_, 42         user0_.question as question62_, 43         user0_.register_date as register13_62_, 44         user0_.role_id as role18_62_, 45         user0_.sex as sex62_, 46         user0_.student_num as student15_62_, 47         user0_.total_online_date as total16_62_, 48         user0_.username as username62_  49     from 50         studentlifesupportplatform.user user0_  51     where 52         user0_.username=? 53 WARN  net.sf.json.JSONObject 54 Property 'handler' has no read method. SKIPPED 55 Hibernate:  56     select 57         role0_.id as id61_0_, 58         role0_.role_permissions as role2_61_0_, 59         role0_.role_type as role3_61_0_  60     from 61         studentlifesupportplatform.role role0_  62     where 63         role0_.id=? 64 Hibernate:  65     select 66         users0_.role_id as role18_1_, 67         users0_.id as id1_, 68         users0_.id as id62_0_, 69         users0_.address as address62_0_, 70         users0_.age as age62_0_, 71         users0_.answer as answer62_0_, 72         users0_.email as email62_0_, 73         users0_.fixed_telephone as fixed6_62_0_, 74         users0_.img_url as img7_62_0_, 75         users0_.nickname as nickname62_0_, 76         users0_.password as password62_0_, 77         users0_.phonenumber as phonenu10_62_0_, 78         users0_.qq as qq62_0_, 79         users0_.question as question62_0_, 80         users0_.register_date as register13_62_0_, 81         users0_.role_id as role18_62_0_, 82         users0_.sex as sex62_0_, 83         users0_.student_num as student15_62_0_, 84         users0_.total_online_date as total16_62_0_, 85         users0_.username as username62_0_  86     from 87         studentlifesupportplatform.user users0_  88     where 89         users0_.role_id=? 90 WARN  net.sf.json.JSONObject 91 Property 'transactionTimeout' has no read method. SKIPPED 92 WARN  net.sf.json.JSONObject 93 Property 'URL' has no read method. SKIPPED 94 WARN  net.sf.json.JSONObject 95 Property 'array' has no read method. SKIPPED 96 WARN  net.sf.json.JSONObject 97 Property 'asciiStream' has no read method. SKIPPED 98 WARN  net.sf.json.JSONObject 99 Property 'bigDecimal' has no read method. SKIPPED100 WARN  net.sf.json.JSONObject101 Property 'binaryStream' has no read method. SKIPPED102 WARN  net.sf.json.JSONObject103 Property 'blob' has no read method. SKIPPED104 WARN  net.sf.json.JSONObject105 Property 'boolean' has no read method. SKIPPED106 WARN  net.sf.json.JSONObject107 Property 'byte' has no read method. SKIPPED108 WARN  net.sf.json.JSONObject109 Property 'bytes' has no read method. SKIPPED110 WARN  net.sf.json.JSONObject111 Property 'characterStream' has no read method. SKIPPED112 WARN  net.sf.json.JSONObject113 Property 'clob' has no read method. SKIPPED114 ERROR  freemarker.runtime115 Method public java.lang.String org.apache.commons.lang.exception.NestableRuntimeException.getMessage(int) threw an exception when invoked on net.sf.json.JSONException: java.lang.reflect.InvocationTargetException116 Method public java.lang.String org.apache.commons.lang.exception.NestableRuntimeException.getMessage(int) threw an exception when invoked on net.sf.json.JSONException: java.lang.reflect.InvocationTargetException117 The problematic instruction:118 ----------119 ==> ${msg[0]} [on line 68, column 29 in org/apache/struts2/dispatcher/error.ftl]120 ----------121 122 Java backtrace for programmers:123 ----------124 freemarker.template.TemplateModelException: Method public java.lang.String org.apache.commons.lang.exception.NestableRuntimeException.getMessage(int) threw an exception when invoked on net.sf.json.JSONException: java.lang.reflect.InvocationTargetException125     at freemarker.ext.beans.SimpleMethodModel.exec(SimpleMethodModel.java:130)126     at freemarker.ext.beans.SimpleMethodModel.get(SimpleMethodModel.java:138)127     at freemarker.core.DynamicKeyName.dealWithNumericalKey(DynamicKeyName.java:111)128     at freemarker.core.DynamicKeyName._getAsTemplateModel(DynamicKeyName.java:90)129     at freemarker.core.Expression.getAsTemplateModel(Expression.java:89)130     at freemarker.core.Expression.getStringValue(Expression.java:93)131     at freemarker.core.DollarVariable.accept(DollarVariable.java:76)132     at freemarker.core.Environment.visit(Environment.java:210)133     at freemarker.core.MixedContent.accept(MixedContent.java:92)134     at freemarker.core.Environment.visit(Environment.java:210)135     at freemarker.core.IfBlock.accept(IfBlock.java:82)136     at freemarker.core.Environment.visit(Environment.java:210)137     at freemarker.core.IteratorBlock$Context.runLoop(IteratorBlock.java:179)138     at freemarker.core.Environment.visit(Environment.java:417)139     at freemarker.core.IteratorBlock.accept(IteratorBlock.java:102)140     at freemarker.core.Environment.visit(Environment.java:210)141     at freemarker.core.MixedContent.accept(MixedContent.java:92)142     at freemarker.core.Environment.visit(Environment.java:210)143     at freemarker.core.IfBlock.accept(IfBlock.java:82)144     at freemarker.core.Environment.visit(Environment.java:210)145     at freemarker.core.MixedContent.accept(MixedContent.java:92)146     at freemarker.core.Environment.visit(Environment.java:210)147     at freemarker.core.Environment.process(Environment.java:190)148     at freemarker.template.Template.process(Template.java:237)149     at org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:797)150     at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:519)151     at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)152     at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)153     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)154     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)155     at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)156     at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)157     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)158     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)159     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)160     at org.apache.catalina.core.StandardContextValve.__invoke(StandardContextValve.java:123)161     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java)162     at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)163     at org.apache.catalina.core.StandardHostValve.__invoke(StandardHostValve.java:171)164     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java)165     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)166     at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)167     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)168     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)169     at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)170     at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)171     at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)172     at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)173     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)174     at java.lang.Thread.run(Thread.java:662)175 Caused by: java.lang.NullPointerException176     at freemarker.ext.beans.SimpleMemberModel.unwrapArguments(SimpleMemberModel.java:85)177     at freemarker.ext.beans.SimpleMethodModel.exec(SimpleMethodModel.java:106)178     ... 49 more179 2014-6-3 1:07:12 org.apache.catalina.core.StandardWrapperValve invoke180 严重: Servlet.service() for servlet [default] in context with path [/StudentLifeSupportPlatformSystem] threw exception181 java.lang.IllegalStateException: Cannot call sendError() after the response has been committed182     at org.apache.catalina.connector.ResponseFacade.sendError(ResponseFacade.java:451)183     at org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:801)184     at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:519)185     at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)186     at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)187     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)188     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)189     at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)190     at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)191     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)192     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)193     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)194     at org.apache.catalina.core.StandardContextValve.__invoke(StandardContextValve.java:123)195     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java)196     at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)197     at org.apache.catalina.core.StandardHostValve.__invoke(StandardHostValve.java:171)198     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java)199     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)200     at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)201     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)202     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)203     at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)204     at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)205     at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)206     at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)207     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)208     at java.lang.Thread.run(Thread.java:662)

欢迎讨论交流，

我的邮箱：zone.technology.exchange@gmail.com