Hibernate:映射另一个表列中的值

Question

我有一个域实体看起来像这样:

class Exch{
    private int id;
    private String val1;
    private String val2;

    @Column(name = "val1")        
    public String getVal1(){
        return val1;  
    }
    @Column(name = "val2")
    public String getVal2(){
        return val2;
    }
    @Column(name = "id")
    public int id(){
        return id;
    }
}

和表:

EXCH

---

Exch_ID | VAL1 | VAL2

---

100000 | AAA | BBB

200000 | CCC | DDD

现在我有另一张表,看起来像:

exch_extra

---

Exch_ID | VAL3 | VAL4

---

100000 | ZZZ | YYY

200000 | XXX | UUU

无论如何我可以将exch_extra表中的val3映射到Entity Exch而不创建额外的Exch_extra实体？

所以我可以:

class Exch{
    private int id;
    private String val1;
    private String val2;
    private String val3;


    @Column(name = "val1")        
    public String getVal1(){
        return val1;  
    }
    @Column(name = "val2")
    public String getVal2(){
        return val2;
    }
    @ do something here so i can have val3 from exch_extra table
    public String val3(){
        return val3
    }

    @Column(name = "id")
    public int id(){
        return id;
    }
 }

Answer 1

Hibernate有一个@SecondaryTable注释,可以帮助您将多个表映射到实体.

只需添加辅助表注释,连接列(在辅助表中)注释.

然后映射其他列,如:

@Column(name="val3", table="table2")
private int val3;

这里table2是另一个表的名称.