[Hibernate]多个字段共同构成主键

表SWPBusinessToDo 拥有2个字段，一起构成主键。

//表的主体映射
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "TB_SWP_BusinessToDo")
@SuppressWarnings("serial")
public class SWPBusinessToDo implements java.io.Serializable{
	@Id
	private SWPBusinessToDoPK id;

	public SWPBusinessToDoPK getId() {
		return id;
	}
	public void setId(SWPBusinessToDoPK id) {
		this.id = id;
	}
}
//将形成主键的字段抽取出来，单独做一个嵌套映射。
//要求重写了equals 跟 hashCode 方法。
import javax.persistence.Column;
import javax.persistence.Embeddable;

@Embeddable
public class SWPBusinessToDoPK implements java.io.Serializable{

	private static final long serialVersionUID = 1L;

	private Long businessId;

	private String operator;

	@Column(name = "businessId", nullable = true, unique = false, insertable = true, updatable = true)
	public Long getBusinessId() {
		return businessId;
	}

	public void setBusinessId(Long businessId) {
		this.businessId = businessId;
	}
	@Column(name = "operator", nullable = true, unique = false, insertable = true, updatable = true)
	public String getOperator() {
		return operator;
	}

	public void setOperator(String operator) {
		this.operator = operator;
	}
        
	@Override
	public boolean equals(Object obj) {
		if(obj instanceof SWPBusinessToDoPK){
			SWPBusinessToDoPK pk = (SWPBusinessToDoPK)obj;
			if(pk.getBusinessId() == this.businessId && 
					pk.getOperator().equals(this.operator)){
				return true;
			}
		}
		return false;
	}

	@Override
	public int hashCode() {
		return (this.operator + this.businessId).hashCode();
	}
	
}

使用的时候，例如：

    SWPBusiness  = new SWPBusinessToDo();
    SWPBusinessToDoPK pk = new SWPBusinessToDoPK();
    pk.setBusinessId( businessId);
    pk.setOperator(operatorId);
    
    SWPBusiness.setId(pk);