hibernate关系映射学习小结

一、一对多映射(one-to-many)

hibernateXML配置文件：

<!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>
    <!-- 配置连接目标数据库的属性 -->
    <property name="connection.driver_class">
        oracle.jdbc.OracleDriver
    </property>
    <property name="connection.url">
        jdbc:oracle:thin:@127.0.0.1:1521:xe
    </property>
    <property name="connection.username">etc1616</property>
    <property name="connection.password">123</property>

    <!-- 配置方言 -->
    <property name="dialect">
        org.hibernate.dialect.Oracle10gDialect
    </property>

    <!-- 是否要显示Hibernate生成的sql语句 -->
    <property name="show_sql">true</property>
    <!-- 是否要格式化显示出的SQL -->
    <property name="format_sql">true</property>

    <!-- 打开自动创建DDL -->
     <property name="hbm2ddl.auto">update</property> 

    <!-- 配置C3P0连接池组件 
    <property name="c3p0.max_size">5</property>
    <property name="c3p0.min_size">2</property>
    <property name="c3p0.timeout">5000</property>
    <property name="c3p0.idle_test_period">3000</property>
    <property name="c3p0.acquire_increment">1</property>
    <property name="c3p0.max_statements">150</property>
    -->
    <!-- 开启二级缓存 
    <property name="cache.use_second_level_cache">true</property>-->
    <!-- 指定二级缓存供应商 
    <property name="cache.region.factory_class">
        org.hibernate.cache.ehcache.EhCacheRegionFactory
    </property>
    -->
    

    <!-- 开启查询缓存 
    <property name="cache.use_query_cache">true</property>-->
    <!-- 读取映射文件 -->
    <!--<mapping resource="com/hbm/entity/Account.hbm.xml" />-->
    <!-- <mapping resource="com/hbm/entity/Student.hbm.xml" />
    <mapping resource="com/hbm/entity/Class.hbm.xml" /> -->
    <!-- 读取实体 -->
    <!-- <mapping class="com.hbm.entity.Book" />
    <mapping class="com.hbm.entity.BookInfo" />
    <mapping class="com.hbm.entity.Customer" />
    <mapping class="com.hbm.entity.Order" /> 
    <mapping class="com.hbm.entity.Role" />
    <mapping class="com.hbm.entity.User" />-->
    <mapping class="com.hbm.entity.Category" /> 
    <mapping class="com.hbm.entity.Product" />
    <!-- <mapping class="com.hbm.entity.User" />
    <mapping class="com.hbm.entity.Role" /> -->
    
</session-factory>
</hibernate-configuration>

Product类：

package com.hbm.entity;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;


@Entity
@Table(name = "product")
public class Product {

      private Integer id;
      private Category category;
      private String name;
      private String price;
      private String descripton;
        
     
     public Product() {
         // TODO Auto-generated constructor stub
     }
    
     public Product(Category category, String name, String price,String descripton) {
          this.category = category;
          this.name = name;
          this.price = price;
          this.descripton = descripton;
          
     }
     
     @Id
     @GenericGenerator(name = "generator", strategy = "increment")
     @GeneratedValue(generator = "generator")
     @Column(name = "id", unique = true, nullable = false)
     public Integer getId() {
         return this.id;
     }
    
     public void setId(Integer id) {
         this.id = id;
      
     }
    
     //延迟加载：多对一方式
     //关联信息：外键name = "category_id"
     @ManyToOne(fetch = FetchType.LAZY)
     @JoinColumn(name = "category_id")
     public Category getCategory() {
         return this.category;
     }
    
     public void setCategory(Category category) {
         this.category = category;
     }
    
     @Column(name = "name", length = 500)
     public String getName() {
         return this.name;
     }
    
     public void setName(String name) {
         this.name = name;
     }
    
     @Column(name = "price", length = 10)
     public String getPrice() {
         return this.price;
     }
    
     public void setPrice(String price) {
         this.price = price;
     }
    
     @Column(name = "descripton", length = 500)
     public String getDescripton() {
         return this.descripton;
     }
    
     public void setDescripton(String descripton) {
         this.descripton = descripton;
      
     }

    @Override
    public String toString() {
        return "Product [id=" + id + ", category=" + category + ", name="
                + name + ", price=" + price + ", descripton=" + descripton
                + "]";
    }
     

}

Category类：

package com.hbm.entity;

import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;

    
@Entity
@Table(name = "category")
public class Category{

    private Integer id;
    private String name;
    private String description;
    private Set<Product> products = new HashSet<Product>();

     public Category() {
         
     }

     public Category(String name, String description, Set<Product> products) {
         this.name = name;
         this.description = description;
         this.products = products;
         
     }

     //主键 ：@Id 主键生成方式：strategy = "increment"
     //映射表中id这个字段，不能为空，并且是唯一的
     @Id
     @GenericGenerator(name = "generator", strategy = "increment")
     @GeneratedValue(generator = "generator")
     @Column(name = "id", unique = true, nullable = false)
     public Integer getId() {
         return this.id;
     }

     public void setId(Integer id) {
         this.id = id;
     }

     //映射表中name这个字段 ，长度是500
     @Column(name = "name", length = 500)
     public String getName() {
         return this.name;
     }

     public void setName(String name) {
         this.name = name;
     }
     
     //映射表中description这个字段 ，长度是500
     @Column(name = "description", length = 500)
     public String getDescription() {
         return this.description;
     }

     public void setDescription(String description) {
         this.description = description;
     }

     //级联操作：cascade = CascadeType.ALL
     //延迟加载：fetch = FetchType.LAZY
     //映射：mappedBy = "category"
     //一对多方式
     @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "category")
     public Set<Product> getProducts() {
         return this.products;
     }

     public void setProducts(Set<Product> products) {
         this.products = products;
     }

    @Override
    public String toString() {
        return "Category [id=" + id + ", name=" + name + ", description="
                + description + "]";
    }
     

}

 测试类：

package com.hbm.test;

import java.util.Set;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.junit.Test;
import com.hbm.Util.HibernateUtil;
import com.hbm.entity.Category;
import com.hbm.entity.Product;

public class Category_Test {
    
    
    SessionFactory sf=HibernateUtil.getSessionFactory();
    Session session=sf.openSession();
    Transaction ts=session.beginTransaction();
    
    @Test
    public void test1(){
        
        Product p=new Product();
        p.setName("大语文");
        p.setPrice("123");
        p.setDescripton("编程语言");
        
        
        Category c=new Category();
        c.setId(1);
        c.setName("李四");
        c.setDescription("ok");
        
        //建立双向关联
    
        c.getProducts().add(p);
        p.setCategory(c);
        
        session.save(c);
        
        ts.commit();
        session.close();
        
        
    }
    
    
    @Test
    public void test2(){
        
        Category c=(Category)session.get(Category.class, 1);
        Set<Product> p=c.getProducts();
        for(Product product:p){
            System.out.println(product);
        }
        System.out.println(c);
        ts.commit();
        
    }

             
}

三、多对多映射(many-to-many)

hibernateXML配置文件：

<!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>
    <!-- 配置连接目标数据库的属性 -->
    <property name="connection.driver_class">
        oracle.jdbc.OracleDriver
    </property>
    <property name="connection.url">
        jdbc:oracle:thin:@127.0.0.1:1521:xe
    </property>
    <property name="connection.username">etc1616</property>
    <property name="connection.password">123</property>

    <!-- 配置方言 -->
    <property name="dialect">
        org.hibernate.dialect.Oracle10gDialect
    </property>

    <!-- 是否要显示Hibernate生成的sql语句 -->
    <property name="show_sql">true</property>
    <!-- 是否要格式化显示出的SQL -->
    <property name="format_sql">true</property>

    <!-- 打开自动创建DDL -->
     <property name="hbm2ddl.auto">update</property> 

    <!-- 配置C3P0连接池组件 
    <property name="c3p0.max_size">5</property>
    <property name="c3p0.min_size">2</property>
    <property name="c3p0.timeout">5000</property>
    <property name="c3p0.idle_test_period">3000</property>
    <property name="c3p0.acquire_increment">1</property>
    <property name="c3p0.max_statements">150</property>
    -->
    <!-- 开启二级缓存 
    <property name="cache.use_second_level_cache">true</property>-->
    <!-- 指定二级缓存供应商 
    <property name="cache.region.factory_class">
        org.hibernate.cache.ehcache.EhCacheRegionFactory
    </property>
    -->
    

    <!-- 开启查询缓存 
    <property name="cache.use_query_cache">true</property>-->
    <!-- 读取映射文件 -->
    <!--<mapping resource="com/hbm/entity/Account.hbm.xml" />-->
    <!-- <mapping resource="com/hbm/entity/Student.hbm.xml" />
    <mapping resource="com/hbm/entity/Class.hbm.xml" /> -->
    <!-- 读取实体 -->
    <!-- <mapping class="com.hbm.entity.Book" />
    <mapping class="com.hbm.entity.BookInfo" />
    <mapping class="com.hbm.entity.Customer" />
    <mapping class="com.hbm.entity.Order" /> 
    <mapping class="com.hbm.entity.Role" />
    <mapping class="com.hbm.entity.User" />-->
    <mapping class="com.hbm.entity.User" />
    <mapping class="com.hbm.entity.Role" />
    
</session-factory>
</hibernate-configuration>

User类：

package com.hbm.entity;

import java.util.ArrayList;
import java.util.List;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;

@Entity(name="hbl_user")
public class User {
    
    private int user_id;
    private String user_name;
    private List<Role> rs_id=new ArrayList<Role>();
    
    
    public User() {
        // TODO Auto-generated constructor stub
    }


    public User(int user_id, String user_name, List<Role> rs_id) {
        super();
        this.user_id = user_id;
        this.user_name = user_name;
        this.rs_id = rs_id;
    }

    @Id
    @GeneratedValue
    public int getUser_id() {
        return user_id;
    }


    public void setUser_id(int user_id) {
        this.user_id = user_id;
    }

    @JoinColumn
    public String getUser_name() {
        return user_name;
    }


    public void setUser_name(String user_name) {
        this.user_name = user_name;
    }

    @ManyToMany()
    @JoinTable(
        //中间表的自定义列名,与之相对应的关联表的主键名
        joinColumns=@JoinColumn(name="user_id",referencedColumnName="user_id"),
        //中间表的自定义列名,与之相对应的关联表的主键名
        inverseJoinColumns=@JoinColumn(name="role_id",referencedColumnName="role_id")
    )
    public List<Role> getRs_id() {
        return rs_id;
    }


    public void setRs_id(List<Role> rs_id) {
        this.rs_id = rs_id;
    }
    
    
}

Role类：

package com.hbm.entity;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToMany;


@Entity(name="hbl_role")
public class Role {
    
    private  int role_id;
    private String role_name;
    private  double price;
    private List<User> us_id=new ArrayList<User>();
    
    public Role() {
        // TODO Auto-generated constructor stub
    }

    public Role(int role_id, String role_name, double price, List<User> us_id) {
        super();
        this.role_id = role_id;
        this.role_name = role_name;
        this.price = price;
        this.us_id = us_id;
    }
    
    @Id
    @GeneratedValue
    public int getRole_id() {
        return role_id;
    }

    public void setRole_id(int role_id) {
        this.role_id = role_id;
    }
    
    @Column
    public String getRole_name() {
        return role_name;
    }

    public void setRole_name(String role_name) {
        this.role_name = role_name;
    }

    @Column
    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    @ManyToMany
    public List<User> getUs_id() {
        return us_id;
    }

    public void setUs_id(List<User> us_id) {
        this.us_id = us_id;
    }
    
    
    
    
    
}

测试类：

package com.hbm.test;

import java.util.Iterator;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.junit.Test;
import com.hbm.Util.HibernateUtil;
import com.hbm.entity.Role;
import com.hbm.entity.User;

public class User_Test {

    SessionFactory sf=HibernateUtil.getSessionFactory();
    Session session=sf.openSession();
    Transaction ts=session.beginTransaction();
    
    
    //插入数据
    @Test
    public void test1(){
        
        User u1=new User();
        u1.setUser_name("乔峰");

        User u2=new User();
        u2.setUser_name("段誉");
        
        
        Role c1=new Role();
        c1.setRole_name("丐帮帮主");
        c1.setPrice(100.0);
    
        Role c2=new Role();
        c2.setRole_name("大理王子");
        c2.setPrice(200.0);

        Role c3=new Role();
        c3.setRole_name("武林高手");
        c3.setPrice(300.0);
    
        u1.getRs_id().add(c1);
        u1.getRs_id().add(c3);
        
        u2.getRs_id().add(c1);
        u2.getRs_id().add(c2);
        u2.getRs_id().add(c3);
        
        c1.getUs_id().add(u1);
        c3.getUs_id().add(u2);
        
    
        session.save(u1);
        session.save(u2);
        
        session.save(c1);
        session.save(c2);
        session.save(c3);
        
        ts.commit();
        session.close();
        
        
    }
    
    //查询
    @Test
    public void test2(){
        
        User us =(User) session.get(User.class, 2);
        System.out.println("我的名字是："+us.getUser_name());
        System.out.println("我的角色是：");
        Iterator<Role> it = us.getRs_id().iterator();
        while(it.hasNext()){
            System.out.println(it.next().getRole_name());    
        }
        
        ts.commit();
        session.close();
        
    }
    //删除
    @Test
    public void test3(){
        
        User us =(User) session.get(User.class, 1);
        Role rs =(Role) session.get(Role.class, 3);
        
        us.getRs_id().remove(rs);
        rs.getUs_id().remove(us);
        
        ts.commit();
        session.close();
        
        
    }
    //更新
    @Test
    public void test4(){
        
        User us =(User) session.get(User.class, 2);
        Role rs1 =(Role) session.get(Role.class, 3);
        Role rs2 =(Role) session.get(Role.class, 4);
        
        
        us.getRs_id().remove(rs1);
        rs1.getUs_id().remove(us);
        
        
        us.getRs_id().add(rs2);
        rs2.getUs_id().add(us);
        
        
        ts.commit();    
        session.close();
        
        
    }
    
    
}