hibernate基于注解的组件映射

基于注解的组件映射

在此以person和name为例：
Name实体类

public class Name {
    private String firstName;
    private String lastName;
    //...省略构造方法和getter，setter方法
}

Person实体类

@Entity//声明该类要在表中映射
public class Person {
    private int id;
    private Name name;
    private Date birthday;
    //无参构造
    @Id          // 声明该属性是主键字段
    @GeneratedValue        //声明主键生成策略是自增长
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    /*
        @Embedded:声明该属性组件映射,如果不需要更改name属性在表中字段的默认值，只写该注解即可，如果需要修改name属性在表中字段的默认值，则还需以下配置；
        column = @Column(name = "first_name", length = 10):将组件相应的属性修改为什么值;
         name = "firstName":对组件的那个属性进行修改
    */
    @Embedded
    @AttributeOverrides(value = {
            @AttributeOverride(column = @Column(name = "first_name", length = 10), name = "firstName"),
            @AttributeOverride(column = @Column(name = "last_name", length = 10), name = "lastName") })
    public Name getName() {
        return name;
    }
    public void setName(Name name) {
        this.name = name;
    }
    @Temporal(TemporalType.DATE)
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
}