当我尝试在我的域类上使用 Groovy 的 JsonBuilder 类时，我的 Grails 应用程序及其集成测试抛出 StackOverflowError。我的代码如下所示:
String result = new JsonBuilder(new MyDomainClass())
因为我发现了关于 JsonBuilder 在自引用上循环的文章，所以我将领域类精简到几乎没有:
package com.mycompany.myapp.myarea
class MyDomainClass { }
但堆栈溢出仍然重现。这是踢球者。如果我将 MyDomainClass 的声明移出它的正常位置并移到单元测试所在的文件中(即，将其从包中取出)，JsonBuilder 就会工作。
下面的堆栈跟踪。有什么帮助吗？
谢谢， BGU
java.lang.StackOverflowError
at java.security.AccessController.doPrivileged(Native Method)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallStaticSite(CallSiteArray.java:62)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallSite(CallSiteArray.java:159)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
at java_lang_Class$isArray.call(Unknown Source)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:135)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure2.doCall(JsonOutput.groovy:158)
at sun.reflect.GeneratedMethodAccessor974.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.callClosureForMapEntry(DefaultGroovyMethods.java:3870)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2426)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2443)
at org.codehaus.groovy.runtime.dgm$61.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:154)
at groovy.json.JsonOutput$toJson$0.callStatic(Unknown Source)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:146)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure1.doCall(JsonOutput.groovy:138)
at sun.reflect.GeneratedMethodAccessor978.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at groovy.lang.Closure.call(Closure.java:425)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2157)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2128)
at org.codehaus.groovy.runtime.dgm$59.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:138)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure2.doCall(JsonOutput.groovy:158)
at sun.reflect.GeneratedMethodAccessor974.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.callClosureForMapEntry(DefaultGroovyMethods.java:3870)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2426)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2443)
at org.codehaus.groovy.runtime.dgm$61.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:154)
at groovy.json.JsonOutput$toJson$0.callStatic(Unknown Source)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:146)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure1.doCall(JsonOutput.groovy:138)
at sun.reflect.GeneratedMethodAccessor978.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at groovy.lang.Closure.call(Closure.java:425)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2157)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2128)
at org.codehaus.groovy.runtime.dgm$59.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:138)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure2.doCall(JsonOutput.groovy:158)
at sun.reflect.GeneratedMethodAccessor974.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.callClosureForMapEntry(DefaultGroovyMethods.java:3870)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2426)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2443)
at org.codehaus.groovy.runtime.dgm$61.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:154)
at groovy.json.JsonOutput$toJson$0.callStatic(Unknown Source)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:146)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure1.doCall(JsonOutput.groovy:138)
at sun.reflect.GeneratedMethodAccessor978.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at groovy.lang.Closure.call(Closure.java:425)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2157)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2128)
at org.codehaus.groovy.runtime.dgm$59.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:138)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure2.doCall(JsonOutput.groovy:158)
at sun.reflect.GeneratedMethodAccessor974.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.callClosureForMapEntry(DefaultGroovyMethods.java:3870)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2426)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2443)
at org.codehaus.groovy.runtime.dgm$61.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)...
最佳答案
我稍微进入了代码，JsonBuilder有很多类型检查来决定对象应该怎么写。对于域类，它匹配 Iterable。然后它会尝试遍历它并写入每个项目等。
奇怪的是，在将对象转换为 Iterable 之后，next 返回对象本身....导致无限循环。
如果我写以下内容它会起作用(如果没有显式转换仍然会失败):
String result = new JsonBuilder((Map)(new MyDomainClass().properties))
关于grails - 使用 Groovy 的 JsonBuilder 时 java_lang_Class$isArray.call() 中的 StackOverflowError，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25457501/