使用hibernate创建视图对应的entity时，一直报 No identifier specified for entity 错。查询发现，hibernate映射表的时候entity必须有主键。

但是视图没有主键。解决办法：

给视图创建联合主键，具体操作如下：

1）创建一个包含联合主键的类，并在类上注释@Embeddable

/*** user_role视图的联合主键*/@Embeddablepublic class UserRoleCompositeId implements Serializable{    private static final long serialVersionUID = -3304319243957837925L;    @Column(name = "userid")    int userid;    @Column(name = "sysid")    int sysid;    @Column(name = "sysname")    String sysname;    public int getUserid() {        return userid;    }    public void setUserid(int userid) {        this.userid = userid;    }    public int getSysid() {        return sysid;    }    public void setSysid(int sysid) {        this.sysid = sysid;    }    public String getSysname() {        return sysname;    }    public void setSysname(String sysname) {        this.sysname = sysname;    }    @Override    public boolean equals(Object o) {        if(o instanceof UserRoleCompositeId){            UserRoleCompositeId key = (UserRoleCompositeId)o ;            if(this.userid == key.userid && this.sysname.equals(key.sysname) && this.sysid==key.sysid){                return true ;            }        }        return false ;    }    @Override    public int hashCode() {        return this.sysname.hashCode();    }}

2）在entity类中引用联合主键，并在引用上注解

@Entity@Table(name = "user_role")public class UserRoleView {    @Column(name = "systype")    String systype;    @Column(name = "perkey")    String perkey;    @Id    private UserRoleCompositeId userRoleCompositeId;    public UserRoleCompositeId getUserRoleCompositeId() {        return userRoleCompositeId;    }    public void setUserRoleCompositeId(UserRoleCompositeId userRoleCompositeId) {        this.userRoleCompositeId = userRoleCompositeId;    }    public String getSystype() {        return systype;    }    public void setSystype(String systype) {        this.systype = systype;    }    public String getPerkey() {        return perkey;    }    public void setPerkey(String perkey) {        this.perkey = perkey;    }}

问题即可得到完美解决