更新时ValidationException:在AbstractPersistenceEventListener上刷新实体时发生验证错误

在我的环境中，Config.groovy上有grails.gorm.failOnError=true

package org.example

class Book {

    String title
    String author
    String email

    static constraints = {
        title nullable: false, blank: false
        email nullable: false, blank: false, unique: true //apparently this is the problem..
    }
}

在控制器上，我有：

package org.example

class BookController {

def update() {

        def bookInstance = Book.get(params.id)
        if (!bookInstance) {
            flash.message = message(code: 'default.not.found.message', args: [message(code: 'book.label', default: 'Book'), params.id])
            redirect(action: "list")
            return
        }

        if (params.version) {
            def version = params.version.toLong()
            if (bookInstance.version > version) {
                bookInstance.errors.rejectValue("version", "default.optimistic.locking.failure",
                          [message(code: 'book.label', default: 'Book')] as Object[],
                          "Another user has updated this Book while you were editing")
                render(view: "edit", model: [bookInstance: bookInstance])
                return
            }
        }

        bookInstance.properties = params

        bookInstance.validate()

        if(bookInstance.hasErrors()) {

            render(view: "edit", model: [bookInstance: bookInstance])

        } else {

            bookInstance.save(flush: true)
            flash.message = message(code: 'default.updated.message', args: [message(code: 'book.label', default: 'Book'), bookInstance.id])
            redirect(action: "show", id: bookInstance.id)
        }      
    }
}

为了省钱，没关系。但是，在不设置标题字段的情况下进行更新时，我会得到：

Message: Validation error whilst flushing entity [org.example.Book]:
- Field error in object 'org.example.Book' on field 'title': rejected value []; codes [org.example.Book.title.blank.error.org.example.Book.title,org.example.Book.title.blank.error.title,org.example.Book.title.blank.error.java.lang.String,org.example.Book.title.blank.error,book.title.blank.error.org.example.Book.title,book.title.blank.error.title,book.title.blank.error.java.lang.String,book.title.blank.error,org.example.Book.title.blank.org.example.Book.title,org.example.Book.title.blank.title,org.example.Book.title.blank.java.lang.String,org.example.Book.title.blank,book.title.blank.org.example.Book.title,book.title.blank.title,book.title.blank.java.lang.String,book.title.blank,blank.org.example.Book.title,blank.title,blank.java.lang.String,blank]; arguments [title,class org.example.Book]; default message [Property [{0}] of class [{1}] cannot be blank]

   Line | Method
->>  46 | onApplicationEvent in org.grails.datastore.mapping.engine.event.AbstractPersistenceEventListener
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|   895 | runTask            in java.util.concurrent.ThreadPoolExecutor$Worker
|   918 | run . . . . . . .  in     ''
^   680 | run                in java.lang.Thread

据我所知，问题发生在刷新hibernate会话时，hibernate再次尝试保存对象，然后引发异常

再次尝试保存对象时，再次调用book.validate（），它在数据库中进行新查询以确保电子邮件字段的唯一性。现在，将引发验证异常

但是，当我删除电子邮件的唯一验证属性时，更新会正常执行

我的问题是：这种行为正确吗？Hibernate会自动调用book.save吗

这是示例项目，模拟错误的步骤如下：

• 资料来源：
• grails run应用程序
• 导航到http://localhost:8080/book/book/create
• 创建一个填充所有字段的新实例
• 然后在http://localhost:8080/book/book/edit/1中编辑此实例
• 最后，删除“Title”字段并单击Update，然后抛出异常

在我的环境中，grails版本2.0.3和2.2.1上出现了这种行为

---

谢谢你的帮助！对不起，我的英语很差。。rs..

您实际上验证了两次，首先是：

bookInstance.validate()

其次是：

bookInstance.save(flush: true)

调用

bookInstance.save（flush:true）

a

boolean

时返回。Grails在生成控制器时默认会利用这一点，但由于某种原因，您似乎已经更改了默认生成的控制器Grails

只要替换这个：

    bookInstance.validate()

    if(bookInstance.hasErrors()) {

        render(view: "edit", model: [bookInstance: bookInstance])

    } else {

        bookInstance.save(flush: true)
        flash.message = message(code: 'default.updated.message', args: [message(code: 'book.label', default: 'Book'), bookInstance.id])
        redirect(action: "show", id: bookInstance.id)
    }  

为此：

    if( !bookInstance.save( flush: true ) ) {
        render(view: "edit", model: [bookInstance: bookInstance])
        return
    }