hibernate 迫切左外连接

非迫切：返回list中每部分是数组(不牵手)

迫切:返回list每部分是对象（牵手，只需将左表放入集合中）

//dept业务层

package com.kgc.biz;

import java.util.List;

import org.hibernate.HibernateException;
import org.hibernate.Transaction;

import com.kgc.common.HibernateSessionFactory;
import com.kgc.dao.DeptDao;
import com.kgc.po.Dept;

public class DeptBiz {
	private DeptDao dao = new DeptDao();
	//查询
	public void findTest(){
		Transaction tx = null;
		try {
			tx=HibernateSessionFactory.getSession().beginTransaction();
			String hql = "from Dept d left join fetch d.emps";
			List<Dept> result = dao.find(hql);
			
			for (Dept dept : result) {
				System.out.println(dept);
			}
			tx.commit();
		} catch (HibernateException e) {
			e.printStackTrace();
			if(tx!=null){
				tx.rollback();
			}
		}
	}
	
}

//test

package com.kgc.test;

import com.kgc.biz.DeptBiz;
import com.kgc.biz.EmpBiz;
import com.kgc.po.Dept;
import com.kgc.po.Emp;

public class DeptTest {
	public static void main(String[] args) {
		DeptBiz biz = new DeptBiz(); 
		biz.findTest();
	}

}

//运行结果

  select
        dept0_.DEPTNO as DEPTNO1_0_,
        emps1_.EMPNO as EMPNO0_1_,
        dept0_.DNAME as DNAME1_0_,
        dept0_.LOC as LOC1_0_,
        emps1_.ENAME as ENAME0_1_,
        emps1_.JOB as JOB0_1_,
        emps1_.MGR as MGR0_1_,
        emps1_.HIREDATE as HIREDATE0_1_,
        emps1_.SAL as SAL0_1_,
        emps1_.COMM as COMM0_1_,
        emps1_.DEPTNO as DEPTNO0_1_,
        emps1_.DEPTNO as DEPTNO1_0__,
        emps1_.EMPNO as EMPNO0__ 
    from
        DEPT dept0_ 
    left outer join
        EMP emps1_ 
            on dept0_.DEPTNO=emps1_.DEPTNO
com.kgc.po.Dept@3b35b1f3
com.kgc.po.Dept@3b35b1f3
com.kgc.po.Dept@3b35b1f3
com.kgc.po.Dept@61672bbb
com.kgc.po.Dept@61672bbb
com.kgc.po.Dept@61672bbb
com.kgc.po.Dept@61672bbb
com.kgc.po.Dept@61672bbb
com.kgc.po.Dept@38d30fb
com.kgc.po.Dept@38d30fb
com.kgc.po.Dept@38d30fb
com.kgc.po.Dept@38d30fb
com.kgc.po.Dept@38d30fb
com.kgc.po.Dept@38d30fb
com.kgc.po.Dept@275e538e

--------------------------------------------------打印部门id name size----------------------------------------------------------------------------

	for (Dept dept : result) {
				System.out.println(dept.getDeptno()+"\t"+dept.getDname()+"\t"+dept.getEmps().size());
			}

-----------------运行结果--------------------

10	ACCOUNTING	3
10	ACCOUNTING	3
10	ACCOUNTING	3
20	RESEARCH	5
20	RESEARCH	5
20	RESEARCH	5
20	RESEARCH	5
20	RESEARCH	5
30	SALES	6
30	SALES	6
30	SALES	6
30	SALES	6
30	SALES	6
30	SALES	6
40	OPERATIONS	0

hibernate 迫切左外连接

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