grails - 无法在Grails中使用类 '[Ljava.lang.Object;@589d360c'异常强制转换对象 '[Ljava.lang.Object;'

Question

当我尝试执行具有多个表的查询时，grails应用程序中出现强制转换异常
UserLogin userList = UserLogin.find(“来自UserLogin为ul，UserDetails为ud，其中ul.id = ud.id”)

UserLogin.groovy

class UserLogin {

    String id
    String userName
    String pwd
    static constraints = {

    }

    static mapping = {
        table '[UserLogin]'
        version false
         id column : 'Id', generator: "assigned"
        userName column: 'UserName'
        pwd column:'Password'
    }
}

UserDetails.groovy

class UserDetails {

    int id
    String name
    String age

    static mapping={
        table '[UserDetails]'
        version false
         id column : 'Id', generator: "assigned"
        name column:'Name'
        age column:'Age'
    }
    static constraints = {
    }
}

完整堆栈跟踪

URI:/LearnGrails/userLogin/show/2Class:org.codehaus.groovy.runtime.typehandling.GroovyCastExceptionMessage:Cannot cast object '[Ljava.lang.Object;@589d360c' with class '[Ljava.lang.Object;' to class 'learngrails.UserLogin' due to: groovy.lang.GroovyRuntimeException: Could not find matching constructor for: learngrails.UserLogin(learngrails.UserLogin, learngrails.UserDetails)

环境-Grails 2.5.0和Jdk1.7

当我使用“find”及其与“findAll” 正常工作时，出现此错误。我是新来的grails，请帮忙-谢谢

Answer 1

您不能将find用于交叉连接。如果要获得单个结果，请使用带有额外参数的findAll:

def userList= UserLogin.findAll("from UserLogin as ul, UserDetails as ud where ul.id=ud.id", [max:1])