问在JPA NamedQuery中使用HashSet作为参数抛出IllegalArgumentException

EN

@Entity
@Table(name = "channel")
@NamedQuery(name = "Channel.getPrivateChannel", query = "SELECT pvt from Channel pvt WHERE pvt.state = 3 AND pvt.channelOwnerWorkspace = :channelOwnerWorkspace AND pvt.channelSubscribers = :channelSubscribers")
public class Channel implements Serializable {

...

@Column(nullable = false)
    private int type;

@ManyToOne
    @JoinColumn(name = "workspaceId")
    private Workspace channelOwnerWorkspace;

@ManyToMany(mappedBy = "subscribedChannels", fetch = FetchType.EAGER)
    private Set<User> channelSubscribers;

Parameter value [pt.project.entity.User@4125ce40] did not match expected type [java.util.Set (n/a)]

public Channel findPrivateChannel1(String workspace, Set<User> channelSubscribers) {


///

        Workspace selectedWorkspace = workspaceDAO.findByTitle(workspace);

        try {
            Channel pvtChannel = em.createNamedQuery("Channel.getPrivateChannel", Channel.class)
                    .setParameter("channelOwnerWorkspace", selectedWorkspace)
                    .setParameter("channelSubscribers", channelSubscribers).getSingleResult();