spring jpa 中如何在插入和更新时使用数据库表的默认值？

spring jpa 中如何在插入和更新时使用数据库表的默认值？

使用springside4.2.1，h2数据库，数据库部分脚本：

reate table ss_nodetype (
        id bigint generated by default as identity,
        type varchar(32) not null unique,
        name varchar(255) not null unique,
        poll_period int not null default '60',
        offline_counts tinyint not null default '5',
        description varchar(255) not null default '',
        create_date timestamp not null default CURRENT_TIMESTAMP,
        primary key (id)
    );
里面有些属性自带默认值。
Entity中 NodeType.java 的部分属性：

@Entity
@Table(name = "ss_nodetype")
// 默认的缓存策略.
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class NodeType extends IdEntity {
 
    private String type;
    private String name;
    private int pollPeriod;
    private byte offlineCounts;
    private String description;
    private Date createDate;
 
    public NodeType() {
 
    }
 
    public NodeType(String type, String name) {
        this.type = type;
        this.name = name;
    }
 
    @NotBlank
    @Column(name = "type", updatable = false)
    public String getType() {
        return type;
    }
 
    public void setType(String type) {
        this.type = type;
    }
 
    @NotBlank
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    @NotNull
    @Column(name = "poll_period", insertable = false)
    public int getPollPeriod() {
        return pollPeriod;
    }
 
    public void setPollPeriod(int pollPeriod) {
        this.pollPeriod = pollPeriod;
    }
 
    @NotNull
    @Column(name = "offline_counts", insertable = false)
    public byte getOfflineCounts() {
        return offlineCounts;
    }
 
    public void setOfflineCounts(byte offlineCounts) {
        this.offlineCounts = offlineCounts;
    }
 
    @Column(name = "description", insertable = false)
    public String getDescription() {
        return description;
    }
 
    public void setDescription(String description) {
        this.description = description;
    }
 
    @Column(name = "create_date", updatable = false, insertable = false)
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+08:00")
    public Date getCreateDate() {
        return createDate;
    }
 
    public void setCreateDate(Date createDate) {
        this.createDate = createDate;
    }
}

再进行DAO单元测试时，查询都正常，就插入和更新时（New了一个NodeType），在验证时，不能自动用数据库表的默认值写入，比如对pollPeriod属性，数据库表的默认值是60，验证的却是0，不想在NodeType CLASS中另设默认值。
有没有办法使JPA在SAVE时使用数据库表的默认值？