http://blog.csdn.net/u013185616/article/details/52799166
[{"endsyntime":"2017-11-15 16:31:29","id":2,"intervaltime":"指定日期执行一次","sourcecount":15,"sourcedbid":6,"sourcetable":"test2","startsyntime":"2017-11-15 16:44:52","starttime":"2017-11-15 10:10:10","targettable":"test2"},{"$ref":"$[0]"},{"$ref":"$[0]"}]
我的原因是;添加数据时,new对象时,在循环外new的,list添加数据的时候,每次都add这一个obj.JsonSynModel synm = new JsonSynModel(); //错误的原由,循环添加同一个objfor (synmodel s : list) {synm = new JsonSynModel();synm.setId(s.getId());synm.setWeek(week);synm.setComment(s.getComment());reList.add(synm);}return JSON.toJSONString(reList);原因 : (多表查询,死循环)
循环引用：当一个对象包含另一个对象时，fastjson就会把该对象解析成引用。引用是通过$ref标示的，下面介绍一些引用的描述
"$ref":".." 上一级
"$ref":"@" 当前对象，也就是自引用
"$ref":"$" 根对象
"$ref":"$.children.0" 基于路径的引用，相当于 root.getChildren().get(0)
(解除引用;ssh一对多，多对多维护一端关系，防止多表关联查询出现死循环)
解决办法 : 采用禁止循环引用的方案.
return JSON.toJSONString(reList,SerializerFeature.DisableCircularReferenceDetect);
其中：SerializerFeature.DisableCircularReferenceDetect就是禁止循环引用的方案，我们可以通过枚举类SerializerFeature来查看到底有多少种方式：
public enum SerializerFeature {QuoteFieldNames,UseSingleQuotes,WriteMapNullValue,WriteEnumUsingToString,UseISO8601DateFormat,/*** @since 1.1*/WriteNullListAsEmpty,/*** @since 1.1*/WriteNullStringAsEmpty,/*** @since 1.1*/WriteNullNumberAsZero,/*** @since 1.1*/WriteNullBooleanAsFalse,/*** @since 1.1*/SkipTransientField,/*** @since 1.1*/SortField,/*** @since 1.1.1*/@DeprecatedWriteTabAsSpecial,/*** @since 1.1.2*/PrettyFormat,/*** @since 1.1.2*/WriteClassName,
​/*** @since 1.1.6*/DisableCircularReferenceDetect,
​/*** @since 1.1.9*/WriteSlashAsSpecial,/*** @since 1.1.10*/BrowserCompatible,/*** @since 1.1.14*/WriteDateUseDateFormat,/*** @since 1.1.15*/NotWriteRootClassName,/*** @since 1.1.19*/DisableCheckSpecialChar,/*** @since 1.1.35*/BeanToArray;
​private SerializerFeature(){mask = (1 << ordinal());}
​private final int mask;
​public final int getMask() {return mask;}
​public static boolean isEnabled(int features, SerializerFeature feature) {return (features & feature.getMask()) != 0;}
​public static int config(int features, SerializerFeature feature, boolean state) {if (state) {features |= feature.getMask();} else {features &= ~feature.getMask();}
​return features;}
}
​