合并一对多对象

Question

我有2个实体块和子块，其中sql FOREIGN KEY（id_block）REFERENCES块（id_block），

@Entity
@Table(name = "block")
public class Block {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column
    private long id_block;
    @Column
    private String name;

    @OneToMany(mappedBy = "block",cascade = CascadeType.ALL,fetch = FetchType.EAGER)
    private List<Subblock> subblock = new ArrayList<>();

    public Block() {

    }
    public long getId_block() {
        return id_block;
    }
    public void setId_block(long id_block) {
        this.id_block = id_block;
    }
    public Block(String name) {
        this.name = name;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public List<Subblock> getSubblock() {
        return subblock;
    }
    public void setSubblock(List<Subblock> subblock) {
        this.subblock = subblock;
    }
}
@Entity
@Table(name = "subblock")
public class Subblock {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column
    private long id_subblock;

    @ManyToOne
    @JoinColumn(name="id_block")
    private Block block;

    @Column
    String name;

    public Subblock() {
    }

    public long getId_subblock() {
        return id_subblock;
    }

    public void setId_subblock(long id_subblock) {
        this.id_subblock = id_subblock;
    }


    public Block getBlock() {
        return block;
    }

    public void setBlock(Block block) {
        this.block = block;
    }


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

使用服务将Block对象合并到DB的主要方法。

Block block = new Block();
        Subblock subblock = new Subblock();

        List<Subblock>subblockList= new ArrayList();

        subblock.setName(messageSource.getMessage("block_1.1",new String[]{},locale));
        subblockList.add(subblock);

        block.setName(messageSource.getMessage("block_1",new String[]{},locale));
        block.setSubblock(subblockList);
        try {
                ratingService.add(block);
        }
        catch (NullPointerException e){
            e.printStackTrace();
        }
    }

我如何合并id_block出现在子块表中的对象？虽然在mappedBY的帮助下我连接了类。或者我必须使用双向通信来唤醒它吗？