HQL查询：hibernate独有的查询语言
适用于不复杂的多表查询
示例：
实体类：
package domain;public class Customer { ???????private Long cust_id; ???private String cust_name; ???private String cust_source; ???private String cust_industry; ???private String cust_level; ???private String cust_linkman; ???private String cust_phone; ???private String cust_mobile; ???public Long getCust_id() { ???????return cust_id; ???} ???public void setCust_id(Long cust_id) { ???????this.cust_id = cust_id; ???} ???public String getCust_name() { ???????return cust_name; ???} ???public void setCust_name(String cust_name) { ???????this.cust_name = cust_name; ???} ???public String getCust_source() { ???????return cust_source; ???} ???public void setCust_source(String cust_source) { ???????this.cust_source = cust_source; ???} ???public String getCust_industry() { ???????return cust_industry; ???} ???public void setCust_industry(String cust_industry) { ???????this.cust_industry = cust_industry; ???} ???public String getCust_level() { ???????return cust_level; ???} ???public void setCust_level(String cust_level) { ???????this.cust_level = cust_level; ???} ???public String getCust_linkman() { ???????return cust_linkman; ???} ???public void setCust_linkman(String cust_linkman) { ???????this.cust_linkman = cust_linkman; ???} ???public String getCust_phone() { ???????return cust_phone; ???} ???public void setCust_phone(String cust_phone) { ???????this.cust_phone = cust_phone; ???} ???public String getCust_mobile() { ???????return cust_mobile; ???} ???public void setCust_mobile(String cust_mobile) { ???????this.cust_mobile = cust_mobile; ???} ???@Override ???public String toString() { ???????return "Customer [cust_id=" + cust_id + ", cust_name=" + cust_name + "]"; ???}}自定义工具类：
package utils;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;public class HibernateUtils { ???private static SessionFactory sf; ???????static{ ???????//1 创建,调用空参构造 ???????Configuration conf = new Configuration().configure(); ???????//2 根据配置信息,创建 SessionFactory对象 ????????sf = conf.buildSessionFactory(); ???} ???????//获得session => 获得全新session ???public static Session openSession(){ ???????????????//3 获得session ???????????????Session session = sf.openSession(); ???????????????????????????????return session; ???????????} ???//获得session => 获得与线程绑定的session ???public static Session getCurrentSession(){ ???????//3 获得session ???????Session session = sf.getCurrentSession(); ???????????????return session; ???} ???}测试类：
package hql;import java.util.List;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.Transaction;import org.junit.Test;import domain.Customer;import utils.HibernateUtils;//测试HQL语句public class Demo { ???@Test ???//基本查询 ???public void fun1(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//1> 书写HQL语句 ???????//String hql = " from domain.Customer "; ???????String hql = " from Customer "; // 如果查询所有Customer对象，可省略全名 ???????//2> 根据HQL语句创建查询对象 ???????Query query = session.createQuery(hql); ???????//3> 根据查询对象获得查询结果 ???????List<Customer> list = query.list(); ???// 返回list结果 ???????//query.uniqueResult();//接收唯一的查询结果 ???????????????System.out.println(list); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???} ???????@Test ???//条件查询 ???//HQL语句中,不可能出现任何数据库相关的信息的 ???//不会出现数据库的表名类名字段名，使用的是实体类的属性名 ???public void fun2(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//1> 书写HQL语句 ???????String hql = " from Customer where cust_id = 1 "; // 查询所有Customer对象 ???????//2> 根据HQL语句创建查询对象 ???????Query query = session.createQuery(hql); ???????//3> 根据查询对象获得查询结果 ???????Customer c = (Customer) query.uniqueResult(); ???????????????System.out.println(c); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????} ???????@Test ???//条件查询 ???//问号占位符 ???public void fun3(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//1> 书写HQL语句 ???????String hql = " from Customer where cust_id = ? "; // 查询所有Customer对象 ???????//2> 根据HQL语句创建查询对象 ???????Query query = session.createQuery(hql); ???????//设置参数 ???????//query.setLong(0, 1l); ???????query.setParameter(0, 1l); ???????//3> 根据查询对象获得查询结果 ???????Customer c = (Customer) query.uniqueResult(); ???????????????System.out.println(c); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????} ???????@Test ???//条件查询 ???//命名占位符 ???public void fun4(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//1> 书写HQL语句 ???????String hql = " from Customer where cust_id = :cust_id "; // 查询所有Customer对象 ???????//2> 根据HQL语句创建查询对象 ???????Query query = session.createQuery(hql); ???????//设置参数 ???????query.setParameter("cust_id", 1l); ???????//3> 根据查询对象获得查询结果 ???????Customer c = (Customer) query.uniqueResult(); ???????????????System.out.println(c); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????} ???????@Test ???//分页查询 ???public void fun5(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//1> 书写HQL语句 ???????String hql = " from Customer ?"; // 查询所有Customer对象 ???????//2> 根据HQL语句创建查询对象 ???????Query query = session.createQuery(hql); ???????//设置分页信息 limit ?,? ???????query.setFirstResult(0); ???????query.setMaxResults(1); ???????//3> 根据查询对象获得查询结果 ???????List<Customer> list = ?query.list(); ???????????????System.out.println(list); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????}}Criteria查询：
hibernate独创的，无语句面向对象查询
适用于单表查询
示例：
package criteria;import java.util.List;import org.hibernate.Criteria;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.Transaction;import org.hibernate.criterion.Projections;import org.hibernate.criterion.Restrictions;import org.junit.Test;import domain.Customer;import utils.HibernateUtils;//测试Criteria查询public class Demo { ???@Test ???//基本查询 ???public void fun1(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????????????//查询所有的Customer对象 ???????Criteria criteria = session.createCriteria(Customer.class); ???????????????List<Customer> list = criteria.list(); ???????????????System.out.println(list); ???????// ???????Customer c = (Customer) criteria.uniqueResult(); ???????????????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????} ???????@Test ???//条件查询 ???//HQL语句中,不可能出现任何数据库相关的信息的 ???// > ????????????????gt ???// >= ???????????????ge ???// < ???????????????lt ???// <= ???????????????le ???// == ???????????????eq ???// != ???????????????ne ???// in ???????????????in ???// between and ???????between ???// like ????????????like ???// is not null ????????isNotNull ???// is null ???????????isNull ???// or ???????????????or ???// and ???????????????and ???public void fun2(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//创建criteria查询对象 ???????Criteria criteria = session.createCriteria(Customer.class); ???????//添加查询参数 => 查询cust_id为1的Customer对象 ???????criteria.add(Restrictions.gt("cust_id", 1l)); ???????//执行查询获得结果 ???????Customer c = (Customer) criteria.uniqueResult(); ???????System.out.println(c); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????} ???????????????@Test ???//分页查询 ???public void fun3(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//创建criteria查询对象 ???????Criteria criteria = session.createCriteria(Customer.class); ???????//设置分页信息 limit ?,? ???????criteria.setFirstResult(1); ???????criteria.setMaxResults(2); ???????//执行查询 ???????List<Customer> list = criteria.list(); ???????????????System.out.println(list); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????} ???????@Test ???//查询总记录数 ???public void fun4(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//创建criteria查询对象 ???????Criteria criteria = session.createCriteria(Customer.class); ???????//设置查询的聚合函数 => 总行数 ???????criteria.setProjection(Projections.rowCount()); ???????//执行查询 ???????Long count = (Long) criteria.uniqueResult(); ???????????????System.out.println(count); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????}}原生SQL查询：
适用于相当复杂的业务
package sql;import java.util.Arrays;import java.util.List;import org.hibernate.SQLQuery;import org.hibernate.Session;import org.hibernate.Transaction;import org.junit.Test;import domain.Customer;import utils.HibernateUtils;//测试原生SQL查询public class Demo { ???@Test ???//基本查询 ???public void fun1(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//1 书写sql语句 ???????String sql = "select * from cst_customer"; ???????????????//2 创建sql查询对象 ???????SQLQuery query = session.createSQLQuery(sql); ???????????????//3 调用方法查询结果 ???????List<Object[]> list = query.list(); ???????//query.uniqueResult(); ???????????????for(Object[] objs : list){ ???????????System.out.println(Arrays.toString(objs)); ???????} ???????????????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????} ???????@Test ???//基本查询 ???public void fun2(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//1 书写sql语句 ???????String sql = "select * from cst_customer"; ???????????????//2 创建sql查询对象 ???????SQLQuery query = session.createSQLQuery(sql); ???????//指定将结果集封装到哪个对象中 ???????query.addEntity(Customer.class); ???????????????//3 调用方法查询结果 ???????List<Customer> list = query.list(); ???????????????System.out.println(list); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????} ???????@Test ???//条件查询 ???public void fun3(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//1 书写sql语句 ???????String sql = "select * from cst_customer where cust_id = ? "; ???????????????//2 创建sql查询对象 ???????SQLQuery query = session.createSQLQuery(sql); ???????????????query.setParameter(0, 1l); ???????//指定将结果集封装到哪个对象中 ???????query.addEntity(Customer.class); ???????????????//3 调用方法查询结果 ???????List<Customer> list = query.list(); ???????????????System.out.println(list); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????} ???????@Test ???//分页查询 ???public void fun4(){ ???????//1 获得session ???????Session session = HibernateUtils.openSession(); ???????//2 控制事务 ???????Transaction tx = session.beginTransaction(); ???????//3执行操作 ???????//------------------------------------------- ???????//1 书写sql语句 ???????String sql = "select * from cst_customer ?limit ?,? "; ???????????????//2 创建sql查询对象 ???????SQLQuery query = session.createSQLQuery(sql); ???????????????query.setParameter(0, 0); ???????query.setParameter(1, 1); ???????//指定将结果集封装到哪个对象中 ???????query.addEntity(Customer.class); ???????????????//3 调用方法查询结果 ???????List<Customer> list = query.list(); ???????????????System.out.println(list); ???????//------------------------------------------- ???????//4提交事务.关闭资源 ???????tx.commit(); ???????session.close(); ???????????????????}}hibernate框架学习笔记7：HQL查询、Criteria查询
原文地址：https://www.cnblogs.com/xuyiqing/p/8452954.html