Criteria是面向物件的無語句查詢

Demo.java

package com.legend.b_criteria;

import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Restrictions;
import org.junit.jupiter.api.Test;

import com.legend.domain.Customer;
import com.legend.utils.HibernateUtils;

/**
 * 學習Criteria語法
 * @author qichunlin
 *
 */
public class Demo {
    //基本語法
    @Test 
    public void fun1() {
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();
        //--------------
        Criteria criteria = session.createCriteria(Customer.class);
        
        
        List<Customer> list = criteria.list();
        System.out.println(list);
        //--------------
        
        tx.commit();
        session.close();
        
    }
    
    //條件查詢
    @Test
    public void fun2(){
        //
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();
        //--------------
        //建立Criteria 物件
        Criteria criteria = session.createCriteria(Customer.class);
        
        //新增Criteria的查詢引數
        criteria.add(Restrictions.eq("cust_id", 1l));
        
        //獲取查詢的結果
        Customer c = (Customer) criteria.uniqueResult();
        System.out.println(c);
        //--------------
        
        //事務的提交
        tx.commit();
        session.close();
        
    
    }
    
    //分頁查詢
    //(當前頁數-1)*每頁條數
    @Test
    public void fun3() {
        //
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();
        //--------------
        //編寫HQL語句
        Criteria criteria = session.createCriteria(Customer.class);
        
        criteria.setFirstResult(1);
        criteria.setMaxResults(2);
        
        List<Customer> list = criteria.list();
        System.out.println(list);
        //--------------
        
        tx.commit();
        session.close();
        
    }
    
    //排序檢索
    @Test
    public void fun5() {
        //
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();
        //--------------
        Criteria criteria = session.createCriteria(Customer.class);
        
        criteria.addOrder(Order.desc("cust_id"));
        
        List<Customer> list = criteria.list();
        System.out.println(list);
        //--------------
        
        tx.commit();
        session.close();
        
    }
    
    //統計查詢
    @Test
    public void fun6() {
        //
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();
        //--------------
        //編寫HQL語句
        Criteria criteria = session.createCriteria(Customer.class);
        
        //設定查詢目標
        criteria.setProjection(Projections.rowCount());
        //List list = query.list();
        List<Long> list = criteria.list();
        System.out.println(list);
        //--------------
        
        tx.commit();
        session.close();
        
    }
}
 

基本查詢

統計查詢

附上hibernate的額核心配置檔案xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<!-- 配置引數檔案 -->
<hibernate-configuration>
    <session-factory>
        <!-- 
            #hibernate.dialect org.hibernate.dialect.MySQLDialect
            #hibernate.dialect org.hibernate.dialect.MySQLInnoDBDialect
            #hibernate.dialect org.hibernate.dialect.MySQLMyISAMDialect
            #hibernate.connection.driver_class com.mysql.jdbc.Driver
            #hibernate.connection.url jdbc:mysql:///test
            #hibernate.connection.username gavin
            #hibernate.connection.password
            配置mysql相關引數
         -->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql:///crm</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">123456</property>
        
        <!-- 配置mysql方言 -->
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
        
        <!-- 
            sql語句顯示
            #hibernate.show_sql true
            # format SQL in log and console
            #hibernate.format_sql true
        
         -->
        <property name="hibernate.format_sql">true</property>
        <property name="hibernate.show_sql">true</property>
        
        <!-- 
            ## auto schema export
            #hibernate.hbm2ddl.auto create-drop
            #hibernate.hbm2ddl.auto create
            #hibernate.hbm2ddl.auto update
            #hibernate.hbm2ddl.auto validate
         -->
        <property name="hibernate.hbm2ddl.auto">update</property>
        
        <!-- 
            設定資料庫隔離級別
            ## specify a JDBC isolation level
            #hibernate.connection.isolation 4
         -->
         <property name="hibernate.connection.isolation">4</property>
        
        <!-- 指定session與當前執行緒繫結 -->
        <property name="hibernate.current_session_context_class">thread</property>
        
        <!-- 配置對映檔案載入 orm元資料 -->
        <mapping resource="com/legend/domain/Customer.hbm.xml"/>
        <mapping resource="com/legend/domain/LinkMan.hbm.xml" />
        <mapping resource="com/legend/domain/User.hbm.xml" />
        <mapping resource="com/legend/domain/Role.hbm.xml" />
        
        
    </session-factory>
</hibernate-configuration>  
 

傳統的Criteria

離線的Criteria