一对多关联在groovy中出现堆栈溢出错误，并使用grails.Please检查类下方，记录是否存在任何关联错误

Question

在使用grails的groovy中，一对多的关联会导致堆栈覆盖流错误。请检查下面的类，错误日志，看看是否有任何关联。错误。

这就是我到目前为止所尝试的：

之前的关联是从B到C类，现在我们在进行此关联更改后将其修改为A到B类。更改对我来说很好，但是当从A类访问b的时候，它抛出了来自A.groovy的堆栈溢出错误getBs方法。如果我删除getBs方法，它会给出null作为B，即使b在db中可用于合约。此外，调用B.findAllByContract动态查找器方法时，它的抛出无法解析属性'a‘，即使它在类级别可用。你能带我到这里吗？

class A implements Serializable {
    static stampable = true
    static auditable = true
    static hasMany = [
        bs: B]
    static mapping = {
        bs joinTable: [column: "a_id"]
    }
    static mappedBy = [ bs: "a"]
    def getBs() {
        println "calling ..."
        return bs
    }
}
class B implements Serializable { 
    A a
    static constraints = {
        a nullable:true
    }
    static mapping = {
        sort title: "asc"
        a column: "a_id"
    }
    static transients = ['BValue']
}

错误日志：

2021-03-28 13:06:10,825 {yyyy-MM-dd HH:mm:ss} admin ERROR org.apache.catalina.core.ContainerBase.[Tomcat].[localhost].[/app].[grailsDispatcherServlet] - Servlet.service() for servlet [grailsDispatcherServlet] in context with path [/app] threw exception [Handler processing failed; nested exception is java.lang.StackOverflowError] with root cause
java.lang.StackOverflowError: null
        at org.codehaus.groovy.runtime.InvokerHelper.format(InvokerHelper.java:583)
        at org.codehaus.groovy.runtime.InvokerHelper.format(InvokerHelper.java:575)
        at org.codehaus.groovy.runtime.InvokerHelper.toString(InvokerHelper.java:130)
        at org.codehaus.groovy.runtime.DefaultGroovyMethods.println(DefaultGroovyMethods.java:642)
        at org.codehaus.groovy.runtime.dgm$504.invoke(Unknown Source)
        at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoMetaMethodSiteNoUnwrapNoCoerce.invoke(PogoMetaMethodSite.java:251)
        at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.callCurrent(PogoMetaMethodSite.java:59)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:166)
        at app.A.getBs(A.groovy:245)
        at sun.reflect.GeneratedMethodAccessor878.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springsource.loaded.ri.ReflectiveInterceptor.jlrMethodInvoke(ReflectiveInterceptor.java:1426)
        at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
        at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
        at groovy.lang.MetaClassImpl.getProperty(MetaClassImpl.java:1852)
        at groovy.lang.ExpandoMetaClass.getProperty(ExpandoMetaClass.java:1155)
        at groovy.lang.MetaClassImpl.getProperty(MetaClassImpl.java:3735)
        at groovy.lang.ExpandoMetaClass.getProperty(ExpandoMetaClass.java:1167)
        at org.codehaus.groovy.runtime.callsite.PogoMetaClassGetPropertySite.getProperty(PogoMetaClassGetPropertySite.java:51)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGroovyObjectGetProperty(AbstractCallSite.java:307)
        at app.A.getBs(A.groovy:246)
        at sun.reflect.GeneratedMethodAccessor878.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springsource.loaded.ri.ReflectiveInterceptor.jlrMethodInvoke(ReflectiveInterceptor.java:1426)
        at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
        at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
        at groovy.lang.MetaClassImpl.getProperty(MetaClassImpl.java:1852)
        at groovy.lang.ExpandoMetaClass.getProperty(ExpandoMetaClass.java:1155)
        at groovy.lang.MetaClassImpl.getProperty(MetaClassImpl.java:3735)
        at groovy.lang.ExpandoMetaClass.getProperty(ExpandoMetaClass.java:1167)
        at org.codehaus.groovy.runtime.callsite.PogoMetaClassGetPropertySite.getProperty(PogoMetaClassGetPropertySite.java:51)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGroovyObjectGetProperty(AbstractCallSite.java:307)
        at app.A.getBs(A.groovy:246)
        at sun.reflect.GeneratedMethodAccessor878.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)

Answer 1

尝试更新getBs方法，如下所示：

def getBs() {
    println "calling ..."
    return this.bs
}

我认为引用bs可能是递归地调用getBs()。