当手动分配ID时，Spring Data MongoDB注释@CreatedDate不起作用

Question

我正在尝试使用审核在对象中保存dateCreated和保存dateUpdated，但是由于我是ID手动设置的，因此还有一些其他工作。

遵循Oliver
Gierke在DATAMONGO-946中的建议，
我试图弄清楚如何正确实现它。

作为上述Jira任务中的原始海报，我从此处https://github.com/spring-guides/gs-accessing-data-
mongodb.git下载了示例，并对其进行了一些修改：

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();
    }
}

执行的结果是：

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``null在对象更新后变为。

我在这里想念什么？以及如何正确实施Persistable以使审核工作正常进行？

Answer 1

您的代码按预期工作。实施后，Persistable您可以看到@CreatedDate注释正在工作。

确定createdDate是null第二次调用，save因为该对象已存在于数据库中，并且已使用进行了更新createdDate = null。从文档中可以看到@CreatedDate：

@CreatedDate批注。该字段标识当实体首次持久存储到数据库时其值已设置的字段。

因此createdDate，null在第二次调用时不要覆盖您的，您应该使用从数据库中检索客户c = repository.findOne("test_id");，然后对其进行更新。