grails：不能使用现有的mysql字段作为不是auto_generated的id

Question

我的问题与我已经得到答案的问题略有不同：link

我有以下域类：

@ToString(includeNames = true, includeFields = true, excludes = 'dateCreated,lastUpdated,metaClass')
@EqualsAndHashCode
class Users {

    Integer userId
    Integer roleId
    String username
    String email

    static constraints = {
        roleId blank:false, nullable:false
        username blank:false, nullable:false
        email blank:true, nullable:true
    }

    static mapping = {
        table 'users'
        version false
        id name:'userId', column:'user_id', sqlType:'int'
        roleId name:'roleId', column:'role_id', sqlType:'int'
    }
}

MySql数据库表： 列：

user_id int(11) PK 
role_id int(11) 
username varchar(32) 
email varchar(255)

修改后的默认生成的控制器来执行JSON CRUD：

@Transactional
class UsersController extends RestfulController {
    static responseFormats = ['json', 'xml']

GET工作正常，但是当我发布POST时，我收到错误：

curl -i -X POST -H "Content-Type: application/json" -d "{userId:2, roleId:1, username:'testId1', email:'test.id@test.com'}" http://test.xxx.com:8090/test/Users

错误：

2014-06-16 15:46:49,458 [http-bio-8090-exec-5] ERROR errors.GrailsExceptionResolver  - StaleObjectStateException occurred when processing request: [POST] /test/Users
Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) : [com.xxx.Users#2]. Stacktrace follows:
Message: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) : [com.xxx.Users#2]
    Line | Method
->>   44 | $tt__save in com.xxx.UsersController$$EOhNaqPu
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|    198 | doFilter  in grails.plugin.cache.web.filter.PageFragmentCachingFilter
|     63 | doFilter  in grails.plugin.cache.web.filter.AbstractFilter
|   1145 | runWorker in java.util.concurrent.ThreadPoolExecutor
|    615 | run . . . in java.util.concurrent.ThreadPoolExecutor$Worker
^    724 | run       in java.lang.Thread

编辑： 控制器代码：

import static org.springframework.http.HttpStatus.*

import com.xxx.domain.Users;

import grails.rest.RestfulController;
import grails.transaction.Transactional

@Transactional
class UsersController extends RestfulController {
    static responseFormats = ['json', 'xml']

    static allowedMethods = [save: "POST", update: "PUT", delete: "DELETE"]

    def index(Integer max) {
        params.max = Math.min(max ?: 10, 100)
        response.setHeader("Access-Control-Allow-Origin", "*")
        respond Users.list(params), model:[usersInstanceCount: Users.count()]
    }

    def show(Users usersInstance) {
        respond usersInstance
    }

    def create() {
        respond new Users(params)
    }

    @Transactional
    def save(Users usersInstance) {
        if (usersInstance == null) {
            notFound()
            return
        }

        if (usersInstance.hasErrors()) {
            respond usersInstance.errors, view:'create'
            return
        }

        usersInstance.save flush:true

        request.withFormat {
            form multipartForm {
                flash.message = message(code: 'default.created.message', args: [message(code: 'users.label', default: 'Users'), usersInstance.id])
                redirect usersInstance
            }
            '*' { respond usersInstance, [status: CREATED] }
        }

    }

    def edit(Users usersInstance) {
        respond usersInstance
    }

    @Transactional
    def update(Users usersInstance) {
        if (usersInstance == null) {
            notFound()
            return
        }

        if (usersInstance.hasErrors()) {
            respond usersInstance.errors, view:'edit'
            return
        }

        usersInstance.save flush:true

        request.withFormat {
            form multipartForm {
                flash.message = message(code: 'default.updated.message', args: [message(code: 'Users.label', default: 'Users'), usersInstance.id])
                redirect usersInstance
            }
            '*'{ respond usersInstance, [status: OK] }
        }
    }

    @Transactional
    def delete(Users usersInstance) {

        if (usersInstance == null) {
            notFound()
            return
        }

        usersInstance.delete flush:true

        request.withFormat {
            form multipartForm {
                flash.message = message(code: 'default.deleted.message', args: [message(code: 'Users.label', default: 'Users'), usersInstance.id])
                redirect action:"index", method:"GET"
            }
            '*'{ render status: NO_CONTENT }
        }
    }

    protected void notFound() {
        request.withFormat {
            form multipartForm {
                flash.message = message(code: 'default.not.found.message', args: [message(code: 'users.label', default: 'Users'), params.id])
                redirect action: "index", method: "GET"
            }
            '*'{ render status: NOT_FOUND }
        }
    }
}