Hibernate中使用原生的sql语句进行查询操作

1. 在Hibernate中使用原生的sql语句进行查询操作

2. 使用HQL查询的一般步骤

2.1 一般的用法 addEntity(Student.class)将查询结果转换为实体类

String sql = "";
session.createSQLQuery(sql).addEntity(Student.class).list();

2.2 使用原生SQL语句，查询Student表里面的记录

public void test03() {
		Session session = HibernateUtils.openSession();
		String sql = "select * from student where id = ?";
		List<Student> stus = session.createSQLQuery(sql)//
				.addEntity(Student.class)//
				.setParameter(0, 1)//
				.list();
		for (Student stu : stus) {
			System.out.println(stu);
		}
	}

3. 在原生sql语句中，使用DTO的方法

3.1 DTO的定义

package com.hibernate.dto;

import java.math.BigInteger;

public class AgeGroup {
	private int age;
	private BigInteger count;

	public AgeGroup() {
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public BigInteger getCount() {
		return count;
	}

	public void setCount(BigInteger count) {
		this.count = count;
	}

	@Override
	public String toString() {
		return "AgeGroup [age=" + age + ", count=" + count + "]";
	}

}

public void test12() {
		Session session = HibernateUtils.openSession();
		// 按照年龄的分组查询
		List<AgeGroup> stus = session
				.createSQLQuery(//
						"select stu.age , count(*) as count  from student stu group by stu.age")//
				.setResultTransformer(Transformers.aliasToBean(AgeGroup.class))//
				.list();
		// 输出查询结果
		for (AgeGroup stu : stus) {
			System.out.println("年龄:" + stu.getAge() + " 的人数为:" + stu.getCount());
		}
	}

4、原生sql语句的连接查询

@Test
	public void test14() {
		Session session = HibernateUtils.openSession();
		// 按照年龄的分组查询
		List<Student> stus = session
				.createSQLQuery(//
						"select stu.*   from student stu join classroom  cla where stu.classid = cla.id and cla.id = ?")//
				.addEntity(Student.class).setParameter(0, 1).list();
		// 输出查询结果
		for (Student stu : stus) {
			System.out.println(stu);
		}
	}