1.Annotation

 

Husband class: @JoinColumns ({@JoinColumn(name="",referencedColumnName="") , @JoinColumn(name="",referencedColumnName="")})

 

@Entity public class Husband {        private int id;        private String name;        private Wife wife;                @Id        @GeneratedValue        public int getId() {            return id;        }        public void setId(int id) {            this.id = id;        }                @OneToOne        //name of the column; By default is (wife_id)        @JoinColumns(           {              　@JoinColumn(name="wifeId",referencedColumnName="id"),                                             @JoinColumn(name="wifeName",referencedColumnName="name")             }        )        public Wife getWife() {            return wife;        }        public void setWife(Wife wife) {            this.wife = wife;        }                public String getName() {            return name;        }        public void setName(String name) {            this.name = name;        }}      @Entity@IdClass(value=WifePK.class)public class Wife {    private int id;    private String name;    private int age;    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    @Id    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    @Id    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }}public class WifePK implements java.io.Serializable{    private int id;    private String name;        public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }        public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }        public boolean equal(Object o){        if(o instanceof WifePK){            WifePK p=(WifePK)o;            if(this.name.equals(p.getName())&&this.id==p.getId()){                return true;            }        }        return false;    }    public int hashCode(){        return this.name.hashCode();    }}

 

2.XML

Student class: under <many-to-one name="xx"> tag, we should name each column of  composite primary key of xx as <column name="xx">