Hibernate学习10——Hibernate 查询方式

Posted 2020-09-30 有点懒惰的大青年

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本章主要是以查询Student的例子：

Student.java:

package com.cy.model;

public class Student {
    private int id;
    private String name;
    private int age;
    
    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";
    }
    
    
    
}

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Student.hbm.xml:

<hibernate-mapping package="com.cy.model">

    <class name="Student" table="t_student">
        <id name="id" column="stuId">
            <generator class="native"></generator>
        </id>
        <property name="name" column="stuName"></property>
        <property name="age" column="stuAge"></property>
    </class>

</hibernate-mapping>

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数据库中student数据：

第一节：Hibernate 查询方式简介　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

导航对象图是说from Student s where s.name = xxx and s.age = xxx这样可以对象.属性这样子；

OID查询方式：比如Session.get(Student.class, 1);根据ID查询这样子;

第二节：本地SQL 查询方式　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

/**
     * 本地sql查询，不带参数
     */
    @Test
    public void testSQLQuery(){
        String sql = "select * from t_student";
        Query query = session.createSQLQuery(sql).addEntity(Student.class);    //查询student，绑定Student实体
        List<Student> studentList = query.list();
        for(Student s: studentList){
            System.out.println(s);
        }
        
        /**
         *  Hibernate: select * from t_student
            Student [id=1, name=张三, age=10]
            Student [id=2, name=李四, age=15]
            Student [id=3, name=王五, age=13]
         */
    }

    /**
     * 本地sql查询，带参数
     * 查询姓名张开头，且10岁
     */
    @Test
    public void testSQLQuery2(){
        String sql = "select * from t_student where stuName like :stuName and stuAge = :stuAge";
        Query query = session.createSQLQuery(sql).addEntity(Student.class);    //查询student，绑定Student实体
        query.setString("stuName", "张%");
        query.setInteger("stuAge", 10);
        List<Student> studentList = query.list();
        for(Student s: studentList){
            System.out.println(s);
        }
        
        /*
         *  Hibernate: select * from t_student where stuName like ? and stuAge = ?
            Student [id=1, name=张三, age=10]
         */
    }

View Code

第三节：HQL 查询方式　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

package com.cy.service;

import java.util.List;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.cy.model.Student;
import com.cy.util.HibernateUtil;

public class StudentTest {

    private SessionFactory sessionFactory=HibernateUtil.getSessionFactory();
    private Session session;
    
    @Before
    public void setUp() throws Exception {
        session=sessionFactory.openSession(); 
        session.beginTransaction();
    }

    @After
    public void tearDown() throws Exception {
         session.getTransaction().commit();
         session.close();
    }
    
    /**
     * 本地sql查询，不带参数
     */
    @Test
    public void testSQLQuery(){
        String sql = "select * from t_student";
        Query query = session.createSQLQuery(sql).addEntity(Student.class);    //查询student，绑定Student实体
        List<Student> studentList = query.list();
        for(Student s: studentList){
            System.out.println(s);
        }
        
        /**
         *  Hibernate: select * from t_student
            Student [id=1, name=张三, age=10]
            Student [id=2, name=李四, age=15]
            Student [id=3, name=王五, age=13]
         */
    }

    /**
     * 本地sql查询，带参数
     * 查询姓名张开头，且10岁
     */
    @Test
    public void testSQLQuery2(){
        String sql = "select * from t_student where stuName like :stuName and stuAge = :stuAge";
        Query query = session.createSQLQuery(sql).addEntity(Student.class);    //查询student，绑定Student实体
        query.setString("stuName", "张%");
        query.setInteger("stuAge", 10);
        List<Student> studentList = query.list();
        for(Student s: studentList){
            System.out.println(s);
        }
        
        /*
         *  Hibernate: select * from t_student where stuName like ? and stuAge = ?
            Student [id=1, name=张三, age=10]
         */
    }
    
    
    /**
     * HQL查询
     */
    @Test
    public void testHQLQuery(){
        String hql = "from Student";
        Query query = session.createQuery(hql);
        List<Student> studentList = query.list();
        for(Student s : studentList){
            System.out.println(s);
        }
        
        /*
         *  Hibernate: select student0_.stuId as stuId1_0_, student0_.stuName as stuName2_0_, student0_.stuAge as stuAge3_0_ from t_student student0_
            Student [id=1, name=张三, age=10]
            Student [id=2, name=李四, age=15]
            Student [id=3, name=王五, age=13]
         */
    }
    
    /**
     * HQL 带条件查询
     */
    @Test
    public void testHQLQuery2(){
        String hql = "from Student where name like :stuName and age = :stuAge ";
        Query query = session.createQuery(hql);
        query.setString("stuName", "张%");
        query.setInteger("stuAge", 10);
        List<Student> studentList = query.list();
        for(Student s : studentList){
            System.out.println(s);
        }
        
        /*
         *  Hibernate: select student0_.stuId as stuId1_0_, student0_.stuName as stuName2_0_, student0_.stuAge as stuAge3_0_ from t_student student0_ where (student0_.stuName like ?) and student0_.stuAge=?
            Student [id=1, name=张三, age=10]
         */
    }
    
    /**
     * HQL 使用别名
     * from Student as s 
     * 或者
     * from Student s
     */
    @Test
    public void testHQLQuery3(){
        String hql="from Student as s where s.name like :stuName and s.age=:stuAge";
        Query query=session.createQuery(hql);
        query.setString("stuName", "张%");
        query.setInteger("stuAge", 10);
        List<Student> studentList= query.list();
        for(Student s : studentList){
            System.out.println(s);
        }
    }
    
    /**
     * HQL查询 对结果排序
     * 按照年龄降序排列
     */
    @Test
    public void testHQLQuery4(){
        String hql = "from Student order by age desc";
        Query query = session.createQuery(hql);
        List<Student> studentList = query.list();
        for(Student s : studentList){
            System.out.println(s);
        }
        
        /*
         *  Hibernate: select student0_.stuId as stuId1_0_, student0_.stuName as stuName2_0_, student0_.stuAge as stuAge3_0_ from t_student student0_ order by student0_.stuAge desc
            Student [id=2, name=李四, age=15]
            Student [id=3, name=王五, age=13]
            Student [id=1, name=张三, age=10]
         */
    }
    
    /**
     * HQL查询  分页查询
     */
    @Test
    public void testHQLQuery5(){
        String hql="from Student";
        Query query=session.createQuery(hql);
        //第1条记录开始，取2条；
        query.setFirstResult(1);        
        query.setMaxResults(2);            
        List<Student> studentList = query.list();
        for(Student s : studentList){
            System.out.println(s);
        }
        
        /*
         *  Hibernate: select student0_.stuId as stuId1_0_, student0_.stuName as stuName2_0_, student0_.stuAge as stuAge3_0_ from t_student student0_ limit ?, ?
            Student [id=2, name=李四, age=15]
            Student [id=3, name=王五, age=13]
         */
    }
    
    /**
     * HQL查询  查询单个对象
     * 查询出一条记录，完全能确定是一条记录，这里就不是list了，uniqueResult
     * 比如查询总记录数，就可以用uniqueResult
     */
    @Test
    public void testHQLQuery6() {
        String hql="from Student";
        Query query=session.createQuery(hql);
        query.setFirstResult(1);
        query.setMaxResults(1);
        Student s = (Student) query.uniqueResult();
        System.out.println(s);    
        
        /*
         *  Hibernate: select student0_.stuId as stuId1_0_, student0_.stuName as stuName2_0_, student0_.stuAge as stuAge3_0_ from t_student student0_ limit ?, ?
            Student [id=2, name=李四, age=15]
         */
    }
    
    /**
     * HQL  链式写法
     */
    @SuppressWarnings("unchecked")
    @Test
    public void testHQLQuery7() {
        String hql = "from Student s where s.name like :stuName and s.age = :stuAge";
        List<Student> studentList = session.createQuery(hql)
                                           .setString("stuName", "李%")
                                           .setInteger("stuAge", 15)
                                           .list();
        for(Student s : studentList){
            System.out.println(s);
        }
        
        /*
         * Student [id=2, name=李四, age=15]
         */
    }
    
    
}

View Code

第四节：QBC 查询方式　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

package com.cy.service;

import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.Restrictions;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.cy.model.Student;
import com.cy.util.HibernateUtil;

public class StudentTest {

    private SessionFactory sessionFactory=HibernateUtil.getSessionFactory();
    private Session session;
    
    @Before
    public void setUp() throws Exception {
        session=sessionFactory.openSession(); 
        session.beginTransaction();
    }

    @After
    public void tearDown() throws Exception {
         session.getTransaction().commit();
         session.close();
    }
    
    
    
    /**
     * QBC查询
     */
    @Test
    public void testQBCQuery(){
        Criteria criteria = session.createCriteria(Student.class);
        List<Student> stuList = criteria.list();
        for(Student s : stuList){
            System.out.println(s);
        }
        
        /*
         *  Hibernate: select this_.stuId as stuId1_0_0_, this_.stuName as stuName2_0_0_, this_.stuAge as stuAge3_0_0_ from t_student this_
            Student [id=1, name=张三, age=10]
            Student [id=2, name=李四, age=15]
            Student [id=3, name=王五, age=13]
         */
    }
    
    /**
     * QBC 带条件查询
     */
    @Test
    public void testQBCQuery2(){
        Criteria criteria = session.createCriteria(Student.class);
        Criterion c1 = Restrictions.like("name", "李%");
        Criterion c2 = Restrictions.eq("age", 15);
        criteria.add(c1);
        criteria.add(c2);
        List<Student> stuList = criteria.list();
        for(Student s : stuList){
            System.out.println(s);
        }
        /*
         *  Hibernate: select this_.stuId as stuId1_0_0_, this_.stuName as stuName2_0_0_, this_.stuAge as stuAge3_0_0_ from t_student this_ where this_.stuName like ? and this_.stuAge=?
            Student [id=2, name=李四, age=15]
         */
    }
    
    /**
     * QBC 对结果排序
     */
    @Test
    public void testQBCQuery3(){
        Criteria criteria = session.createCriteria(Student.class);
        criteria.addOrder(Order.desc("age"));
        List<Student> stuList = criteria.list();
        for(Student s : stuList){
            System.out.println(s);
        }
        
        /*
         *  Student [id=2, name=李四, age=15]
            Student [id=3, name=王五, age=13]
            Student [id=1, name=张三, age=10]
         */
    }
    
    /**
     * QBC 分页查询
     */
    @Test
    public void testQBCQuery4(){
        Criteria criteria = session.createCriteria(Student.class);
        criteria.setFirstResult(0);    //从第0条记录开始
        criteria.setMaxResults(2);    //查询2条
        List<Student> stuList = criteria.list();
        for(Student s : stuList){
            System.out.println(s);
        }
        
        /*
         *  Hibernate: select this_.stuId as stuId1_0_0_, this_.stuName as stuName2_0_0_, this_.stuAge as stuAge3_0_0_ from t_student this_ limit ?
            Student [id=1, name=张三, age=10]
            Student [id=2, name=李四, age=15]
         */
    }
    
    /**
     * QBC 查询单个对象
     * 因为这里只取一条记录，uniqueResult
     */
    @Test
    public void testQBCQuery5(){
        Criteria criteria = session.createCriteria(Student.class);
        criteria.setFirstResult(2);    
        criteria.setMaxResults(1);    
        Student    s = (Student) criteria.uniqueResult();
        System.out.println(s);
        
        /*
         *  Hibernate: select this_.stuId as stuId1_0_0_, this_.stuName as stuName2_0_0_, this_.stuAge as stuAge3_0_0_ from t_student this_ limit ?, ?
            Student [id=3, name=王五, age=13]
         */
    }
    
    /**
     * QBC 链式写法
     */
    @SuppressWarnings("unchecked")
    @Test
    public void testQBCQuery6(){
        Criterion c1 = Restrictions.like("name", "李%");
        Criterion c2 = Restrictions.eq("age", 15);
        List<Student> stuList = session.createCriteria(Student.class)
                                       .add(c1)
                                       .add(c2)
                                       .list();
        for(Student s : stuList){
            System.out.println(s);
        }
    }
    
}

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