使用3列执行连接表映射的最佳方法是什么？

Question

请查看附件中的实体关系图，请为我提供最佳解决方案。

我希望我的ERD关系对这种情况有好处。

在这里，到目前为止我做了什么？随后：Giannigar’s blog

执行此类映射的最佳方法是什么？这些是我的实体类

@Entity
@Table(name = "t")
public class T
{
    //… other fields

    @OneToMany(mappedBy = "t", targetEntity = TMJoin.class, cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    @JsonManagedReference
    private List<TMJoin> tmJoins = new ArrayList<TMJoin>();

//… setter/getter methods
}

@Entity
@Table(name = "m")
public class M
{
    //… other fields 

    @OneToMany(mappedBy = "m", targetEntity = TMJoin.class)
    @JsonBackReference
    private List<TMJoin> tmJoins = new ArrayList<TMJoin>();

    //… setter/getter methods
}

@Entity
@Table(name = "u")
public class U {

    //… other fields 

    @OneToMany(mappedBy = "u", targetEntity = TMJoin.class)
    @JsonBackReference
    private List<TMJoin> tmJoins = new ArrayList<TMJoin>();

    //… setter/getter methods
}


@Entity
@Table(name= "t_m_join")
public class TMJoin
{
    @Id
    @SequenceGenerator(name = "tMJoinSeq", sequenceName = "seq_t_m_join_id", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.IDENTITY, generator = "tMJoinSeq")
    private long id;

    @ManyToOne(targetEntity=T.class, fetch=FetchType.LAZY)      
    @JoinColumns({ @JoinColumn(name="t_id", referencedColumnName="id", nullable=false) })   
    @JsonBackReference
    private T t;

    @ManyToOne(targetEntity=U.class, fetch=FetchType.EAGER)     
    @JoinColumns({ @JoinColumn(name="u_id", referencedColumnName="id", nullable=false) })
    @JsonManagedReference
    private U u;

    @ManyToOne(targetEntity=M.class, fetch=FetchType.EAGER)     
    @JoinColumns({ @JoinColumn(name="m_id", referencedColumnName="id", nullable=false) })
    @JsonManagedReference
    @JsonProperty("m")
    private M m;

//… setter/getter methods
}

也许有更好的方法可以使用额外的参考列进行此类连接表映射？

编辑： 我在保存T对象时遇到错误。

web_1 | ERROR [2016-04-13 15:54:09,619] io.dropwizard.jersey.errors.LoggingExceptionMapper: Error handling a request: 2270a7a8addbc3e7
web_1 | ! java.lang.IllegalArgumentException: Can not handle managed/back reference 'defaultReference': back reference type (java.util.List) not compatible with managed type (com.core.TMJoin)