hibernate两张表关联查询

很久没用过hibernate了，今天尝试了一下多表连接查询，忘记了怎么配置，然后网上搜到了另一种的联合查询方式。

首先是两个实体类，一个用户表，一个商品表

User类

public class User {
	private Integer id;
	private String userName;
	private String phone;
	private String address;

	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	
	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", userName=" + userName + ", phone=" + phone + ", address=" + address + "]";
	}
	
}

Goods商品类

public class Goods {
	private Integer goodId;
	private String goodName;
	private Integer userId;
	public Integer getGoodId() {
		return goodId;
	}
	public void setGoodId(Integer goodId) {
		this.goodId = goodId;
	}
	public String getGoodName() {
		return goodName;
	}
	public void setGoodName(String goodName) {
		this.goodName = goodName;
	}
	public Integer getUserId() {
		return userId;
	}
	public void setUserId(Integer userId) {
		this.userId = userId;
	}
	@Override
	public String toString() {
		return "Goods [goodId=" + goodId + ", goodName=" + goodName + ", userId=" + userId + "]";
	}
	
}

这里就不上传hibernate的cfg和hbm的映射了。

这时候想要多表连接可以添加一个第三方的类，把需要的属性都封装到第三个整合的实体类中,并且已构造器的方式传入

UserAndGoods整合类

public class UserAndGoods {
	//以下是我们想要查出来的数据
	private String username;
	private String phone;
	private String address;
	private String goodname;
	
	public UserAndGoods() {
		super();
	}
	//想要封装的数据已构造器的方式传入
	public UserAndGoods(String username, String phone, String address, String goodname) {
		super();
		this.username = username;
		this.phone = phone;
		this.address = address;
		this.goodname = goodname;
	}

	public String getUsername() {
		return username;
	}

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

	public String getPhone() {
		return phone;
	}

	public void setPhone(String phone) {
		this.phone = phone;
	}

	public String getAddress() {
		return address;
	}

	public void setAddress(String address) {
		this.address = address;
	}

	public String getGoodname() {
		return goodname;
	}

	public void setGoodname(String goodname) {
		this.goodname = goodname;
	}

	@Override
	public String toString() {
		return "UserAndGoods [username=" + username + ", phone=" + phone + ", address=" + address + ", goodname="
				+ goodname + "]";
	}
	
	
}

测试类

public class Shop {
	@Test
	public void ss(){
		Session session = HibernateUtils.openSession();
		Transaction transaction = session.beginTransaction();
		//在hql语句中直接new我们写好的整合的类，并且用构造器传入
		String hql ="select new com.hbsi.pojo.UserAndGoods(u.userName,u.phone,u.address,g.goodName) from User u,Goods g  where u.id = g.userId and u.id = 1";
		//集合的泛型是整合类
		List list = session.createQuery(hql).list();
		transaction.commit();
		for (UserAndGoods userAndGoods : list) {
			System.out.println(userAndGoods);
		}
		
	}
}

结果：

 这样的方式可以不用写那些复杂的一对多多对一的关系了