The GORM 约束介绍

import grails.persistence.Entity;
import org.grails.datastore.gorm.GormEntity
@Entity
class User implements GormEntity<User>{
    ...

    static constraints = {
        login size: 5..15, blank: false, unique: true
        password size: 5..15, blank: false
        email email: true, blank: false
        age min: 18
    }
}

grails.gorm.default.constraints = {
    '*'(nullable: true, size: 1..20)
}

grails.gorm.default.constraints = {
    myShared(nullable: true, size: 1..20)
}

import grails.persistence.Entity;
import org.grails.datastore.gorm.GormEntity
@Entity
class User implements GormEntity<User>{
    ...

    static constraints = {
        login(shared: "myShared")
    }
}

import grails.persistence.Entity;
import org.grails.datastore.gorm.GormEntity
@Entity
class User implements GormEntity<User>{
    String firstName
    String middleName

    static constraints = {
        firstName blank: false, nullable: false
        middleName blank: true, nullable: true
    }
}

login blank: false

cardNumber creditCard: true

homeEmail email: true

name inList: ["Joe", "Fred", "Bob"]

login matches: "[a-zA-Z]+"

age max: new Date()
price max: 999F

class User {
    ...

    static constraints = {
        //此日期对象在评估约束执行时创建，而不是每次验证用户类的实例时创建
        birthDate max: new Date()
    }
}

children maxSize: 25

age min: new Date()
price min: 0F

class User {
    ...

    static constraints = {
        //此日期对象在评估约束执行时创建，而不是每次验证用户类的实例时创建
        age min: new Date()
    }
}

children minSize: 25

username notEqual: "Bob"

age nullable: true

age range: 18..65

salary scale: 2

children size: 5..15

username unique: true

group unique: 'department'

username(unique: ['group', 'department'])

homePage url: true

even validator: {
    return (it % 2) == 0
}

// is equivalent to
even validator: { val ->
    return (val % 2) == 0
}

// 闭包的两个参数,第一个是属性值，第二个是实例对象
password1 validator: { val, obj ->
    obj.password2 == val
}

//闭包的三个参数,第一个是属性值，第二个是实例对象 ，第三个是errors错误对象
password1 validator: { val, obj, errors ->
    if (!(obj.password2 == val)) errors.rejectValue('password1', 'noMatch')
}

// Examples 传递参数到i18n的消息中 message.properties
// Example 1: 使用隐式的参数 0 (属性名称)

class Person {

    String name

    static constraints = {
        name validator: {
          if (!it) return ['entryMissing']
       }
}

// 上述例子将调用如下消息:
// person.name.entryMissing=Please enter a name in the field {0}

// Example 2: 使用隐式的参数 0 (属性名称) and 参数2 (属性值)

class Person {

    Integer yearOfBirth

    static constraints = {
        yearOfBirth validator: {
          if (yearOfBirth>2013) return ['yearTooBig']
       }
}

// 上述例子将调用如下消息:
// person.yearOfBirth.yearTooBig=The value {2} entered in the field {0} is not valid because it lies in the future.

// Example 3: 复杂

class Astronaut {

    Integer yearOfBirth
    Integer yearOfFirstSpaceTravel

        yearOfFirstSpaceTravel validator: { val, obj ->
                if (val < obj.yearOfBirth) ['datePriorTo', val.toString(), obj.yearOfBirth]
                else if (val < (obj.yearOfBirth+18)) ['maybeABitTooYoung', val-obj.yearOfBirth]
        }
}

// 各自的消息
// 注意，参数3是属性值转换toString方法，以避免不必要的格式，如前所述.
astronaut.yearOfFirstSpaceTravel.datePriorTo=The value {3} entered for the year of the first space travel is prior to the year of birth ({4}). Please correct the value.
astronaut.yearOfFirstSpaceTravel.maybeABitTooYoung={3} years seems a bit young for travelling to space, dude!