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  • hibernate demo配置和使用 -----类与表映射关系

    hibernate.cfg.xml

    <!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
    
    <hibernate-configuration>
        <!-- 通常,一个session-factory节点代表一个数据库 -->
        <session-factory>
        
            <!-- 1. 数据库连接配置 -->
            <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
            <property name="hibernate.connection.url">jdbc:mysql:///hib_demo</property>
            <property name="hibernate.connection.username">root</property>
            <property name="hibernate.connection.password">root</property>
            <!-- 
                数据库方法配置, hibernate在运行的时候,会根据不同的方言生成符合当前数据库语法的sql
             -->
            <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
            
            
            <!-- 2. 其他相关配置 -->
            <!-- 2.1 显示hibernate在运行时候执行的sql语句 -->
            <property name="hibernate.show_sql">true</property>
            <!-- 2.2 格式化sql -->
            <property name="hibernate.format_sql">true</property>
            <!-- 2.3 自动建表  -->
            <property name="hibernate.hbm2ddl.auto">create</property>
            
            
         
            
        </session-factory>
    </hibernate-configuration>

    组件映射:

    car.hbm.xml

    <?xml version="1.0"?>
    <!DOCTYPE hibernate-mapping PUBLIC 
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
        
        
        
    <hibernate-mapping  package="cn.itcast.compomer" >  
        <class name="car"  table="t_car">
        <id name="id" >
        <generator class="native"/>
        
        </id>
        <property name="name" ></property>
        
         <component name="wheel">
         <property name="size"></property>
         <property name="count"></property>
        
         </component>
    
        </class>
        </hibernate-mapping>

    car.java

    package cn.itcast.compomer;
    
    public class car {
    private int id;
    private String name;
    private wheel wheel;
    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 wheel getWheel() {
        return wheel;
    }
    public void setWheel(wheel wheel) {
        this.wheel = wheel;
    }
    
    }

    wheel.java

    package cn.itcast.compomer;
    
    public class wheel {
    private int count;
    private int size;
    public int getCount() {
        return count;
    }
    public void setCount(int count) {
        this.count = count;
    }
    public int getSize() {
        return size;
    }
    public void setSize(int size) {
        this.size = size;
    }
    
    }

    app.java

    public class app {
        private static SessionFactory  sf;
        static {
            sf=new Configuration().configure().addClass(car.class).buildSessionFactory();

    //该处一定要加上 addclass(car.class) 会自动去查找car.hbm.xml

    } @Test
    public void testsave() throws Exception{ Session session=sf.openSession(); session.beginTransaction(); wheel wheel = new wheel(); wheel.setSize(38); wheel.setCount(4); car car= new car(); car.setName("bmw"); car.setWheel(wheel); session.save(car); session.getTransaction().commit(); session.close(); } }

    二,继承映射

    animal.java

    public abstract class animal {
    private int id;
    private String name;
    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;
    }
    
    }

    cat.java

    public class cat  extends animal{
    private String catchmouse;
    
    public String getCatchmouse() {
        return catchmouse;
    }
    
    public void setCatchmouse(String catchmouse) {
        this.catchmouse = catchmouse;
    }
    
    
    }

    cat.hbm.xml

    <?xml version="1.0"?>
    <!DOCTYPE hibernate-mapping PUBLIC 
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
        
        
        
        <hibernate-mapping  package="cn.itcast.extend1" >  
        <class name="cat"  table="t_cat">
        <id name="id">
        <generator class="native"></generator>
        </id>
        <property name="name"></property>
          <property name="catchmouse"></property>
    
        </class>
        </hibernate-mapping>

    hibernate.cfg.xml

    <hibernate-configuration>
        <!-- 通常,一个session-factory节点代表一个数据库 -->
        <session-factory>
        
            <!-- 1. 数据库连接配置 -->
            <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
            <property name="hibernate.connection.url">jdbc:mysql:///hib_demo</property>
            <property name="hibernate.connection.username">root</property>
            <property name="hibernate.connection.password">root</property>
            <!-- 
                数据库方法配置, hibernate在运行的时候,会根据不同的方言生成符合当前数据库语法的sql
             -->
            <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
            
            
            <!-- 2. 其他相关配置 -->
            <!-- 2.1 显示hibernate在运行时候执行的sql语句 -->
            <property name="hibernate.show_sql">true</property>
            <!-- 2.2 格式化sql 
            <property name="hibernate.format_sql">true</property>
            -->
            <!-- 2.3 自动建表  -->
            <property name="hibernate.hbm2ddl.auto">update</property>
            
            
            <!-- 3. 加载所有映射
            <mapping resource="cn/itcast/acollection/user.hbm.xml"/>
             -->
            
        </session-factory>
    </hibernate-configuration>

    app.java

    public class app {
        private static SessionFactory  sf;
        static{
            sf= new Configuration().configure().addClass(cat.class).buildSessionFactory();
            
        }
    
        @Test
        public void getsave(){
            Session  session=sf.openSession();
            session.beginTransaction();
            
    /*  cat  cat= new cat();
      cat.setName("dahuamao");
      cat.setCatchmouse("zhuoxiaolaoshu ");
      session.save(cat);*/                 //hibernate.cfg.xml    <property name="hibernate.hbm2ddl.auto">create</property>  创建表内数据时使用该配置
            



    Query q= session.createQuery("from cat");
    List<cat> list=q.list(); 
    System.out.println(list);
    //hibernate.cfg.xml    <property name="hibernate.hbm2ddl.auto">update</property>   查询表内数据时使用该配置








    session.getTransaction().commit();
    session.close();

    }
    }

    animal.class+ cat.class + monkey.class

    public class monkey extends animal{
    private String eatbanana;
    
    public String getEatbanana() {
        return eatbanana;
    }
    
    public void setEatbanana(String eatbanana) {
        this.eatbanana = eatbanana;
    }
    
    }

    三个类对应 一张数据表

    <?xml version="1.0"?>
    <!DOCTYPE hibernate-mapping PUBLIC 
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
    
        <hibernate-mapping  package="cn.itcast.extend2.copy" >  
        <class name="animal"  table="t_animal">
        <id name="id">
        <generator class="native"></generator>
        </id>
        
        < 三个类对应到一张表    需要使用到 筛选器   >
        <discriminator column="type_"></discriminator>
        <property name="name"></property>
        
        
          <subclass  name="cat"  discriminator-value="cat_">
          <property name="catchmouse"></property>
          </subclass>
    
          <subclass   name="monkey" discriminator-value="monkey_">
          <property name="eatbanana"></property>
          </subclass>
        </class>
        </hibernate-mapping>
            cat cat= new cat();
            cat.setName("大茂华");
            cat.setCatchmouse("捉小老鼠");
            
            monkey m= new monkey();
            m.setName("猴子");
            m.setEatbanana("吃了10个香蕉");
            
            session.save(cat);
            session.save(m);

    三个类对应三个表           animal表 :   1  cat     2  monkey  ;      cat 表 ;    monkey 表  

    <hibernate-mapping  package="cn.itcast.extend2.copy" >  
        <class name="animal"  table="t_animal">
        <id name="id">
        <generator class="native"></generator>
        </id>
    
        <property name="name"></property>
        
        <joined-subclass name="cat" table="t_cat">
        <key column ="t_animal_id"></key>
        <property name="catchmouse"></property>
        </joined-subclass>
        
         <joined-subclass  name="monkey"  table="t_monkey">
         <key column="t_animal_id"></key>
         <property name="eatbanana"></property>
         
         </joined-subclass>
        </class>
        </hibernate-mapping>

    每个子类映射一张表,父类不对应表(2张表)

    <hibernate-mapping  package="cn.itcast.extend2.copy" >  
        <class name="animal"  table="t_animal">
        <id name="id">
        <!-- 如果用union-subclass节点 主键生成策略不能为自增长  不能使用native -->
        <generator class="uuid"></generator>
        </id>
    
        <property name="name"></property>
        <union-subclass name="cat"  table="t_cat">
        <property name="catchmouse"></property>
        
        </union-subclass>
        
         <union-subclass name="monkey"  table="t_monkey">
        <property name="eatbanana"></property>
        
        </union-subclass>
        </class>
        </hibernate-mapping>
    public abstract class animal {
    private String id;     //   使用uuid后   int  id  需要更改为  String id ;
    private String name;
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
    }
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  • 原文地址:https://www.cnblogs.com/yimian/p/7883227.html
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