当手动分配ID时，Spring Data MongoDB Annotation @CreatedDate不起作用 [英] Spring Data MongoDB Annotation @CreatedDate isn't working, when ID is assigned manually

问题描述

我正在尝试使用审核在我的对象中保存 dateCreated 和 dateUpdated ，但是因为我设置了 ID 手动，还有一些额外的工作。

I'm trying to use auditing to save dateCreated and dateUpdated in my objects, but since I set ID manually, there's some additional work.

遵循Oliver Gierke在 DATAMONGO-946
我正在试图弄清楚如何正确实现它。

Following Oliver Gierke's suggestion in DATAMONGO-946 I'm trying to figure out how to correctly implement it.

作为上面Jira任务的原始海报，我从这里下载了示例 https://github.com/spring-guides/gs-accessing-data-mongodb.git 并对其进行了一些修改：

As original poster in Jira task above, I've downloaded example from here https://github.com/spring-guides/gs-accessing-data-mongodb.git and modified it a bit:

package hello;

import org.springframework.data.annotation.CreatedDate;
import org.springframework.data.annotation.Id;
import org.springframework.data.annotation.LastModifiedDate;
import org.springframework.data.domain.Persistable;

import java.util.Date;

public class Customer implements Persistable<String> {
    @Id
    private String id;
    @CreatedDate
    private Date createdDate;
    @LastModifiedDate
    private Date lastModifiedDate;
    private String firstName;
    private String lastName;
    private boolean persisted;

    public Customer() {
    }

    public Customer(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public void setPersisted(boolean persisted) {
        this.persisted = persisted;
    }

    @Override
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    @Override
    public boolean isNew() {
        return !persisted;
    }

    @Override
    public String toString() {
        return String.format(
                "Customer[id=%s, createdDate=%s, lastModifiedDate=%s, firstName='%s', lastName='%s']",
                id, createdDate, lastModifiedDate, firstName, lastName);
    }
}

和

package hello;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.mongodb.config.EnableMongoAuditing;

@SpringBootApplication
@EnableMongoAuditing
public class Application implements CommandLineRunner {

    @Autowired
    private CustomerRepository repository;

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Override
    public void run(String... args) throws Exception {

        repository.deleteAll();

        // create a customer
        Customer c = new Customer("Alice", "Smith");
        c.setId("test_id");

        // save a customer
        repository.save(c);

        // fetch all customers
        System.out.println("Customers found with findAll():");
        System.out.println("-------------------------------");
        for (Customer customer : repository.findAll()) {
            System.out.println(customer);
        }
        System.out.println();

        // create another customer with same id
        c = new Customer("Bob", "Smith");
        c.setId("test_id");
        c.setPersisted(true);
        repository.save(c);

        // fetch all customers
        System.out.println("Customers found with findAll():");
        System.out.println("-------------------------------");
        for (Customer customer : repository.findAll()) {
            System.out.println(customer);
        }
        System.out.println();
    }
}

执行的结果如下：

Customers found with findAll():
-------------------------------
Customer[id=test_id, createdDate=Wed Feb 24 00:43:47 WITA 2016, lastModifiedDate=Wed Feb 24 00:43:47 WITA 2016, firstName='Alice', lastName='Smith']

Customers found with findAll():
-------------------------------
Customer[id=test_id, createdDate=null, lastModifiedDate=Wed Feb 24 00:43:47 WITA 2016, firstName='Bob', lastName='Smith']

createdDate 变为对象更新后为null 。

我在这里缺少什么？如何正确实现 Persistable 以使审核工作正常？

What am I missing here? And how to correctly implement Persistable to make auditing work properly?

推荐答案

您的代码按预期工作。在您实现 Persistable 后，您可以看到 @CreatedDate 注释正在运行。

Your code is working as expected. After you've implemented Persistable you can see that @CreatedDate annotation is working.

第二次调用时，确保 createdDate null 因为该对象已存在于数据库中，并且您使用 createdDate = null 更新了该对象。正如您从 @CreatedDate 的文档中看到的那样：

Sure that createdDate is null on the second call of save because the object already exists in the database and you updated it with createdDate = null. As you can see from the documentation for @CreatedDate:

@CreatedDate注释。这标识了当实体第一次持久保存到数据库时其值设置为
的字段。

@CreatedDate annotation. This identifies the field whose value is set when the entity is persisted to the database for the first time.

所以不是要在第二次调用时用 null 覆盖 createdDate ，您应该使用 c = repository.findOne（test_id）; 然后更新它。

So not to overwrite your createdDate with null on the second call you should retrieve your customer from the database with c = repository.findOne("test_id"); and then update it.

这篇关于当手动分配ID时，Spring Data MongoDB Annotation @CreatedDate不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！