org.hibernate.MappingException： 無法確定 type for ： java.util.Set

虽然这个问题问了很多次，我已经用了所有的建议，但我仍然得到这个错误。

用户.java是

@Entity
@Table(name = "USER")
public class User implements UserDetails, Serializable {

    private static final long serialVersionUID = 2L;

    @Id
    @Column(name = "USER_ID")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;
    @Column(name = "USERNAME")
    private String username;
    @Column(name = "PASSWORD")
    private String password;
    @Column(name = "NAME")
    private String name;
    @Column(name = "EMAIL")
    private String email;
    @Column(name = "LOCKED")
    private boolean locked;
    @OneToMany(cascade=CascadeType.ALL, fetch = FetchType.EAGER)
    @ElementCollection(targetClass=Role.class)
    @Column(name = "ROLE_ID")
    private Set<Role> roles;

    @Override
    public GrantedAuthority[] getAuthorities() {
        List<GrantedAuthorityImpl> list = new ArrayList<GrantedAuthorityImpl>(0);
        for (Role role : roles) {
            list.add(new GrantedAuthorityImpl(role.getRole()));
        }
        return (GrantedAuthority[]) list.toArray(new GrantedAuthority[list.size()]);
    }

    @Override
    public boolean isAccountNonExpired() {
        return true;
    }

    @Override
    public boolean isAccountNonLocked() {
        return !isLocked();
    }

    @Override
    public boolean isCredentialsNonExpired() {
        return true;
    }

    @Override
    public boolean isEnabled() {
        return true;
    }

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public boolean isLocked() {
        return locked;
    }

    public void setLocked(boolean locked) {
        this.locked = locked;
    }

    @Override
    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Override
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }

    public Set<Role> getRoles() {
        return roles;
    }
}

而角色.java是

@Entity
@Table(name="ROLE")
public class Role implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="ROLE_ID")
    private long id;
    @Column(name="USERNAME")
    private String username;
    @Column(name="ROLE")
    private String role;


    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getRole() {
        return role;
    }

    public void setRole(String role) {
        this.role = role;
    }
}

这是我第一次尝试使用 JPA 进行休眠注释。因此，任何建议都将非常有帮助。

对于休眠，pom.xml的依赖项是：

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate</artifactId>
        <version>3.5.4-Final</version>
        <type>pom</type>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-annotations</artifactId>
        <version>3.5.4-Final</version>
        <type>jar</type>
        <scope>compile</scope>
    </dependency>

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>3.5.4-Final</version>
        <type>jar</type>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>3.1.0.GA</version>
        <type>jar</type>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>3.5.4-Final</version>
        <type>jar</type>
        <scope>compile</scope>
    </dependency>

我不知道这个错误。

谢谢。