1.标签描述：
package javax.persistence;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* Specifies that the property or field is not persistent. It is used
* to annotate a property or field of an entity class, mapped
* superclass, or embeddable class.
*
* <pre>
* Example:
*
* @Entity
* public class Employee {
* @Id int id;
* @Transient User currentUser;
* ...
* }
* </pre>
*
* @since Java Persistence 1.0
*/
@Target({ METHOD, FIELD })
@Retention(RUNTIME)
public @interface Transient {
}
核心点：这个标签是用来指定属性或字段，是瞬时状态，不持久化到数据库中。
2.标签放置位置：亲测只有放置到属性的GET方法上，才会起作用!
@Entity
public class Books {
private Integer id;
private String name;
private String author;
private Integer price;
private String description;
private Date createTime;
private Date updateTime;
private String newParameter;
@Transient
public String getNewParameter() {
return newParameter;
}
public void setNewParameter(String newParameter) {
this.newParameter = newParameter;
}
...
控制台Hibernate底层执行的SQL语句：可以看到在String newParameter;对应的GET方法上加上@Transient标签，插入SQL语句将自动排除这个字段。
Hibernate:
insert
into
books
(author, create_time, description, name, price, update_time)
values
(?, ?, ?, ?, ?, ?)
{"description":"好好学习，承担医学传承","id":21,"name":"神农本草经"}
