@CreatedDate注释不适用于mysql

问题描述：

我是Spring的新手，我对@CreatedDate注释在实体中的工作方式感到困惑.

I am new to spring and I am confused how @CreatedDate annotation works in an entity.

我做了一个google搜索，有很多解决方案，但是除了一个解决方案外，没有一个对我有用.我很困惑为什么?

I did a google search and there were many solutions, but none of them worked for me except one. I am confused why?

这是我首先尝试的

@Entity
@EntityListeners(AuditingEntityListener.class)
public class User implements Serializable {

    @Id
    @GeneratedValue
    private Long id;
    private String name;

    @CreatedDate
    private Date created;

    public User(String name) {

        this.name = name;
    }

    public User() {
    }

它没有用.我在created列中的值为NULL.

It did not work. I got NULL for the value in created column.

然后我做到了.

@Entity
@EntityListeners(AuditingEntityListener.class)
public class User implements Serializable {

    @Id
    @GeneratedValue
    private Long id;
    private String name;

    @CreatedDate
    private Date created = new Date();

    public User(String name) {

        this.name = name;
    }

    public User() {
    }

这实际上将时间戳存储在db中.我的问题是我遵循的大多数教程都建议我不需要new Date()即可获取当前时间戳.看起来我确实需要那个.有什么我想念的吗?

This actually stored the time stamp in the db. My question is most of the tutorials I followed suggested that I do not need new Date() to get the current time stamp. Looks like I do need that. Is there anything I am missing?

答

如果仅将@EntityListeners(AuditingEntityListener.class)放在实体上，则@CreatedDate本身将无法工作.为了工作，您必须做一些更多的配置.

The @CreatedDate won't work by itself if you just put @EntityListeners(AuditingEntityListener.class) on your entities. In order, it'll work you have to do a little more configuration.

假设在您的数据库中，@CreatedDate的字段为String类型，并且您想返回当前登录的用户作为@CreatedDate的值，然后执行以下操作:

Let's say that in your DB the field of @CreatedDate is String type, and you want to return the user that is currently logged in as a value for @CreatedDate, then do this:

public class CustomAuditorAware implements AuditorAware<String> {

    @Override
    public String getCurrentAuditor() {
        String loggedName = SecurityContextHolder.getContext().getAuthentication().getName();
        return loggedName;
    }

}

您可以在此处编写任何适合您需求的功能，但是您肯定必须有一个引用实现AuditorAware

You can write there any functionality that fits your needs, but you certainly must have a bean that reference to a class that implements `AuditorAware

同样重要的是，第二部分是创建一个返回带有@EnableJpaAuditing注释的类的Bean，如下所示:

The second part and equally important, is to create a bean that returns that class with annotation of @EnableJpaAuditing, like this:

@Configuration
@EnableJpaAuditing
public class AuditorConfig {

    @Bean
    public CustomAuditorAware auditorProvider(){
        return new CustomAuditorAware();
    }
}

如果您的毒药是XML配置，请执行以下操作:

if your poison is XML configuration then do this:

<bean id="customAuditorAware" class="org.moshe.arad.general.CustomAuditorAware" />
    <jpa:auditing auditor-aware-ref="customAuditorAware"/>

@CreatedDate注释不适用于mysql

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