hibernate_07_单表操作_增删改操作

首先，创建类对象

package com.imooc.hibernate;

public class Address {

    private String postcode; //邮编
    private String phone; //电话
    private String address; //地址
    
    public Address() {};
    
    public String getPostcode() {
        return postcode;
    }
    public void setPostcode(String postcode) {
        this.postcode = postcode;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    public Address(String postcode, String phone, String address) {
//        super();
        this.postcode = postcode;
        this.phone = phone;
        this.address = address;
    }
    @Override
    public String toString() {
        return "Address [postcode=" + postcode + ", phone=" + phone + ", address=" + address + "]";
    }
    
}

package com.imooc.hibernate;

import java.sql.Blob;
import java.util.Date;

public class Students {

    private int sid;
    private String sname;
    private String gender;
    private Date birthday;
    private Address address;
    private Blob picture;
    
    public Blob getPicture() {
        return picture;
    }

    public void setPicture(Blob picture) {
        this.picture = picture;
    }

    public Students() {}

    public Students(int sid, String sname, String gender, Date birthday, Address address, Blob picture) {
        super();
        this.sid = sid;
        this.sname = sname;
        this.gender = gender;
        this.birthday = birthday;
        this.address = address;
        this.picture = picture;
    }

    @Override
    public String toString() {
        return "Students [sid=" + sid + ", sname=" + sname + ", gender=" + gender + ", birthday=" + birthday
                + ", address=" + address + ", picture=" + picture + "]";
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public int getSid() {
        return sid;
    }

    public void setSid(int sid) {
        this.sid = sid;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

}

创建类对象的配置文件

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 2017-5-23 0:24:09 by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
    <class name="com.imooc.hibernate.Students" table="STUDENTS">
        <id name="sid" type="int">
            <column name="SID" />
            <generator class="native" />
        </id>
        <property name="sname" type="java.lang.String">
            <column name="SNAME" />
        </property>
        <property name="gender" type="java.lang.String">
            <column name="GENDER" />
        </property>
        <property name="birthday" type="java.util.Date">
            <column name="BIRTHDAY" />
        </property>
        <property name="picture" type="java.sql.Blob">
            <column name="PICTURE" />
        </property>
        
        <component name="address" class="com.imooc.hibernate.Address">
            <property name="postcode" column="POSTCODE"/>
            <property name="phone" column="PHONE"/>
            <property name="address" column="ADDRESS"/>
        </component>
    </class>
</hibernate-mapping>

创建hibernate配置文件

<?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">
<hibernate-configuration>
    <session-factory>
        <property name="connection.username">root</property>
        <property name="connection.password">root</property>
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/hibernate?useUnicode=true&amp;characterEncoding=UTF-8</property>
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>
        <property name="hbm2ddl.auto">update</property>
        
        <mapping resource="com/imooc/hibernate/Students.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

创建测试类

package com.icoom.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.util.Date;

import org.hibernate.Hibernate;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.imooc.hibernate.Address;
import com.imooc.hibernate.Students;

public class StudentsTest {
    
    private SessionFactory sessionFactory;
    private Session session;
    private Transaction transaction;

    @Before
    public void init() {
        // 1.创建配置对象
        Configuration config = new Configuration().configure();
        // 2.创建服务注册对象
        ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();
        // 3.创建会话工厂对象
        sessionFactory = config.buildSessionFactory(serviceRegistry);
        // 会话对象
        session = sessionFactory.openSession();
        // 开启事务
        transaction = session.beginTransaction();
    }
    
    @After
    public void destory() {
        transaction.commit(); //提交事务
        session.close(); //关闭session
        sessionFactory.close();//关闭会话工厂
    }
    
    @Test
    public void testSaveStudents() {
        Students s = new Students();
        s.setSid(1);
        s.setSname("老张");
        s.setGender("男");
        s.setBirthday(new Date());
        Address address = new Address("250000", "1310531xxxx", "山东济南");
        s.setAddress(address);
        session.save(s);//保存对象进入数据库
    }
    
    @Test
    public void testGetStudents() {
        Students s = (Students) session.get(Students.class, 1);
        System.out.println(s);
    }
    
    @Test
    public void testLoadStudents() {
        Students s = (Students) session.load(Students.class, 1);
        System.out.println(s);
    }
    
    @Test
    public void testUpdateStudents() {
        Students s = (Students) session.get(Students.class, 1);
        s.setGender("女");
        session.update(s);
    }
    
    @Test
    public void testDeleteStudents() {
        Students s = (Students) session.get(Students.class, 1);
        session.delete(s);
    }
}

get和load方法的区别

1. 在不考虑缓存的情况下，get方法会在调用之后立即向数据库发出sql语句，返回持久化对象；load方法会在调用后放回一个代理对象。该代理对象只保存了实体对象的id，知道使用对象的非主键属性时才会发出sql语句。
2. 查询数据库中不存在的数据时，get方法返回null，load方法抛出org.hibernate.ObjectNotFoundException异常。