我正在尝试运行以下简单示例，但出现错误。

我正在使用@CreatedDate。但是，当我使用Rest端点保存Student对象时，它不会创建日期并抛出给定的异常。

在我的休息终点，我有

 @PostMapping("/students")
 public Student createStudent(@Valid @RequestBody Student student){
    return studentRepository.save(student);
 }

这是我的实体…

@Entity
@Table(name = "students")
@EntityListeners(AuditingEntityListener.class)
@JsonIgnoreProperties(value = {"createdAt", "updatedAt"}, allowGetters = true)
public class Student implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @NotBlank
    private String name;
    @NotBlank
    private String surname;

    @Column(nullable = false, updatable = false)
    @Temporal(TemporalType.TIMESTAMP)
    @CreatedDate
    private Date createdAt;

    @Column(nullable = false)
    @Temporal(TemporalType.TIMESTAMP)
    @LastModifiedDate
    private Date updatedAt;

错误：

2018-06-20 21:43:40.821 DEBUG 8844 --- [nio-8080-exec-1] org.hibernate.SQL

    : select next_val as id_val from hibernate_sequence for update
2018-06-20 21:43:40.874 DEBUG 8844 --- [nio-8080-exec-1] org.hibernate.SQL                        : update hibernate_sequence set next_val= ? where next_val=?
2018-06-20 21:43:40.971 DEBUG 8844 --- [nio-8080-exec-1] org.hibernate.SQL                        : insert into students (created_at, name, surname, updated_at, id) values (?, ?, ?, ?, ?)
2018-06-20 21:43:40.978 TRACE 8844 --- [nio-8080-exec-1] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [TIMESTAMP] - [null]
2018-06-20 21:43:40.979 TRACE 8844 --- [nio-8080-exec-1] o.h.type.descriptor.sql.BasicBinder      : binding parameter [2] as [VARCHAR] - [Shilpa]
2018-06-20 21:43:40.980 TRACE 8844 --- [nio-8080-exec-1] o.h.type.descriptor.sql.BasicBinder      : binding parameter [3] as [VARCHAR] - [Manware]
2018-06-20 21:43:40.980 TRACE 8844 --- [nio-8080-exec-1] o.h.type.descriptor.sql.BasicBinder      : binding parameter [4] as [TIMESTAMP] - [null]
2018-06-20 21:43:40.981 TRACE 8844 --- [nio-8080-exec-1] o.h.type.descriptor.sql.BasicBinder      : binding parameter [5] as [BIGINT] - [3]
2018-06-20 21:43:41.003  WARN 8844 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper   : SQL Error: 1048, SQLState: 23000
2018-06-20 21:43:41.003 ERROR 8844 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper   : Column 'created_at' cannot be null
2018-06-20 21:43:41.006  INFO 8844 --- [nio-8080-exec-1] o.h.e.j.b.internal.AbstractBatchImpl     : HHH000010: On release of batch it still contained JDBC statements
2018-06-20 21:43:41.009 ERROR 8844 --- [nio-8080-exec-1] o.h.i.ExceptionMapperStandardImpl        : HHH000346: Error during managed flush [org.hibernate.exception.ConstraintViolationException: could not execute statement]
2018-06-20 21:43:41.041 ERROR 8844 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement] with root cause

com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column 'created_at' cannot be null
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_112]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_112]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_112]
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_112]
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) ~[mysql-connector-java-5.1.45.jar:5.1.45]
    at com.mysql.jdbc.Util.getInstance(Util.java:408) ~[mysql-connector-java-5.1.45.jar:5.1.45]
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:936) ~[mysql-connector-java-5.1.45.jar:5.1.45]
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973) ~[mysql-connector-java-5.1.45.jar:5.1.45]
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909) ~[mysql-connector-java-5.1.45.jar:5.1.45]
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527) ~[mysql-connector-java-5.1.45.jar:5.1.45]