Grails：动态findBy方法抛出没有方法签名...适用于参数类型

Question

在我的Player域类中，我试图在自定义验证器中使用动态生成的findByNumber方法来查找具有相同编号的现有Player实例。完整的域类如下。

当我运行我的Grails应用程序并有目的地尝试使用生成的脚手架网页创建新播放器时，会抛出以下异常：

Class: groovy.lang.MissingMethodException
Message: No signature of method: com.sciotofootball.Player.findByNumber() is applicable for argument types: (java.lang.Integer) values: [15]

是否允许在自定义验证器中使用动态生成的findBy方法？

class Player {
    // Min and max values
    static final MIN_GRADE  = Holders.config.player.grade.min.toInteger()
    static final MAX_GRADE  = Holders.config.player.grade.max.toInteger()
    static final MIN_NUMBER = Holders.config.player.number.min.toInteger()
    static final MAX_NUMBER = Holders.config.player.number.max.toInteger()
    static final MIN_WEIGHT = Holders.config.player.weight.min.toInteger()
    static final MAX_WEIGHT = Holders.config.player.weight.max.toInteger()

    // This pattern matches as follows
    // Feet (5 or 6)-Inches (0-12)
    static final HEIGHT_PATTERN = "[56]\\-(([0-9]{1})|([12]{1}[0-1]{1}))"

    // Valid football positions
    static final VALID_POSITIONS = [
        // Offense
        "QB", "RB", "WR", "TE", "OL",
        // Defense
        "DL", "LB", "DB",
        // Special teams
        "P", "K"
    ]

    Integer number;
    String firstName;
    String lastName;
    Integer grade;
    String position1;
    String position2;
    String height;
    Integer weight;

    static constraints = {
        // unique: true adds unique index to the player table
        // number nullable: false, unique: true, min: MIN_NUMBER, max: MAX_NUMBER
        number nullable: false, min: MIN_NUMBER, max: MAX_NUMBER, validator: { numberValue ->
            Player existingPlayer = findByNumber( numberValue )
            return ( existingPlayer == null ?: [ 'unique', existingPlayer.firstName, existingPlayer.lastName ] )
        }
        firstName blank: false
        lastName blank: false
        grade nullable: false, range: MIN_GRADE..MAX_GRADE
        position1 blank: false, inList: VALID_POSITIONS
        position2 nullable: true, inList: VALID_POSITIONS, validator: { position2Value, player ->
            // Position 2 cannot be equal to position 1
            return ( player.position1 != position2Value ?: [ 'duplicate' ] )
        }
        height blank: false, matches: HEIGHT_PATTERN
        weight nullable: false, min: MIN_WEIGHT, max: MAX_WEIGHT
    }
}