02.基本查询
package com.gordon.test;import java.text.DecimalFormat;import java.util.Arrays;import java.util.List;import org.hibernate.Session;import org.hibernate.Transaction;import org.junit.Test;import com.gordon.domain.Book;import com.gordon.utils.HibernateUtil;public class TestDemo1 { /** * 分组查询 * 查询结果： Hibernate: select publisher1_.name as col_0_0_, count(*) as col_1_0_ from t_book book0_, t_publisher publisher1_ where book0_.publisher_id=publisher1_.id group by book0_.publisher_id [电子工业出版社, 3] [北京大学出版社, 2] [人民邮电出版社, 2] */ @Test public void run5() { Session session = HibernateUtil.getCurrentSession(); Transaction transaction = session.beginTransaction(); List list = session.createQuery("select b.publisher.name, count(*) from Book b group by b.publisher").list(); for (Object[] book : list) { System.out.println(Arrays.toString(book)); } transaction.commit(); } /** * 聚合函数 * 查询结果： Hibernate: select count(*) as col_0_0_ from t_book book0_ Hibernate: select sum(book0_.price) as col_0_0_ from t_book book0_ Hibernate: select max(book0_.price) as col_0_0_, min(book0_.price) as col_1_0_ from t_book book0_ Hibernate: select avg(book0_.price) as col_0_0_ from t_book book0_ count: 7 sum: 330.04 Max:70.00 Min:31.00 avg: 47.15 */ @Test public void run4() { Session session = HibernateUtil.getCurrentSession(); Transaction transaction = session.beginTransaction(); String count = "select count(*) from Book"; Long c = (Long) session.createQuery(count).uniqueResult(); String sum = "select sum(b.price) from Book b"; Double s = (Double) session.createQuery(sum).uniqueResult(); String maxmin = "select max(b.price), min(b.price) from Book b"; Object[] mm = (Object[]) session.createQuery(maxmin).uniqueResult(); String avg = "select avg(b.price) from Book b"; Double a = (Double) session.createQuery(avg).uniqueResult(); DecimalFormat df = new DecimalFormat("00.00"); System.out.println("count: " + c); System.out.println("sum: " + df.format(s)); System.out.println("Max:" + df.format(mm[0]) + " Min:" + df.format(mm[1])); System.out.println("avg: " + df.format(a)); transaction.commit(); } /** * 检索图书对象的部分属性 * 查询结果 Hibernate: select book0_.name as col_0_0_, book0_.price as col_1_0_ from t_book book0_ order by book0_.price desc [云计算技术及性能优化, 70.0] [架构探险：轻量级微服务架构（下册）, 63.2] [中国冰雪梦, 54.0] [生产微服务 , 44.0] [VisualBasic2015实践教程 , 36.0] [Photoshop图形图像处理, 31.84] [C语言程序设计, 31.0] */ @Test public void run3() { Session session = HibernateUtil.getCurrentSession(); Transaction transaction = session.beginTransaction(); List list = session.createQuery("select b.name, b.price from Book b order by b.price desc").list(); for (Object[] book : list) { System.out.println(Arrays.toString(book)); } transaction.commit(); } /** * 对查询结果进行排序 * 查询结果： Hibernate: select book0_.id as id1_0_, book0_.name as name2_0_, book0_.price as price3_0_, book0_.publisher_id as publishe4_0_ from t_book book0_ order by book0_.price desc 70.0, 云计算技术及性能优化 63.2, 架构探险：轻量级微服务架构（下册） 54.0, 中国冰雪梦 44.0, 生产微服务 36.0, VisualBasic2015实践教程 31.84, Photoshop图形图像处理 31.0, C语言程序设计 */ @Test public void run2() { Session session = HibernateUtil.getCurrentSession(); Transaction transaction = session.beginTransaction(); List list = session.createQuery("from Book b order by b.price desc").list(); for (Book book : list) { System.out.println(book.getPrice() + ", " + book.getName()); } transaction.commit(); } /** * 查询所有图书 * 查询结果： Hibernate: select book0_.id as id1_0_, book0_.name as name2_0_, book0_.price as price3_0_, book0_.publisher_id as publishe4_0_ from t_book book0_ 云计算技术及性能优化 C语言程序设计 中国冰雪梦 Photoshop图形图像处理 VisualBasic2015实践教程 生产微服务 架构探险：轻量级微服务架构（下册） */ @Test public void run1() { Session session = HibernateUtil.getCurrentSession(); Transaction transaction = session.beginTransaction(); List list = session.createQuery("from Book").list(); for (Book book : list) { System.out.println(book.getName()); } transaction.commit(); }}