java 范围映射 java 根据类型映射java

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mob64ca1414c613 2023-09-07 12:25:28

文章标签 java 范围映射 java hibernate List Test 文章分类 Java 后端开发

集合映射应用场景

1.用于一对多的场景

2.用于少量比较单一的数据

一、集合类型来分

1.List

@ElementCollection(targetEntity=String.Class)

@CollectionTable(name="t_name")//生成数据库的名字

@Orderby//必须加

@OrderColumn(name="orderindex") //排列字段

private List<String> names

List有序

@ElementCollection(targetEntit=String.Class)

@CollectionTable(name="t_names")

private Set<String> names;

Set无序不可重复

@ElementCollection(targehtEntity=String.Class)

@CollectionTable(name="t_names")

@MapKeyProperty(name="key")

private Map<String,String> names;

Map

二、.数据类型来分

基本数据类型

@ElementCollection(targetEntity=基本数据类型)

嵌入式数据类型要求: 1.实现序列化接口 2.重写hashCode和equals方法 3.加@Embeddable

@ElementCollection(targetEntity=嵌入式数据类型)

联合主键（嵌入式类）

1.实现序列化接口

2.重写hashcode 和 equals方法

3.载类上加@Embeddable

一对多单向

package com.oracle.bean;

import lombok.Data;
import org.hibernate.annotations.GenericGenerator;

import javax.persistence.*;
import java.util.List;
import java.util.Set;

/**
 * 产品的分类
 */
//营养套餐 水果礼盒 箱装水果 国产水果 进口水果 干货食品
@Entity
@Data
@Table(name="TCatalog")
public class Catalog {

    @Id
    @GeneratedValue(generator= "uuid")
    @GenericGenerator(name="uuid",strategy = "uuid")
    private String cataid;

    private String cataname;


    /**
     * 在关系映射中一对多的情况和我们 平常在使用集合映射是一样
     * List set Map来描述这种关系
     * list @orderby
     * map @mapKeyProperty
     * @oneToMany 用于一方
     * @joinColumn 通知多方去建立一个外键关联字段catalogid 来关联我的主键
     * 在表中给你添加一个字段 存放就是顺序  1 2 3
     */
    @OneToMany(cascade = CascadeType.ALL)
    @JoinColumn(name="catalogid")
    @OrderBy("orderindex desc")
    private List<Product> products;



}

package com.oracle.bean;

import lombok.Data;
import org.hibernate.annotations.GenericGenerator;

import javax.persistence.*;
import java.math.BigDecimal;

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

    @Id
    @GeneratedValue(generator = "uuid")
    @GenericGenerator(name="uuid",strategy = "uuid")
    private String pid;

    /**
     * 商品的名称
     */
    private String pname;

    /**
     * 商品简介
     */
    private String pinfo;

    /**
     * 商品的编号
     */
    private String productcode;

    private String  artno;

    private String unit;

    private BigDecimal price;

    private BigDecimal saleprice;

    private int score;

    private BigDecimal discount;

    /**
     * 库存量
     */
    private BigDecimal pcount;

    private String remark;


    private int orderindex;

}

package com.oracle.core;


import com.oracle.bean.Catalog;
import com.oracle.bean.Product;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;


public class One2ManyTest {
   private SessionFactory sessionFactory;
   private Session session;
   private  Product product;

    @Before
    public void  begin(){
        Configuration cfg=new Configuration();
        cfg.configure();
        sessionFactory=cfg.buildSessionFactory();
        session=sessionFactory.openSession();
        session.beginTransaction();
    }


    //现在描述的关系 一对多 关系维护端 是 一的一方
    //单向关联 操作一方 另外一方也会收到影响  增删查改的动作
    //级联的保存 当我们保存分类的时候 级联的保存我分类下的所有的商品
    //营养套餐 水果礼盒 箱装水果 国产水果 进口水果 干货食品
    @Test
    public void save()
    {
        Catalog shuiguolihe=new Catalog();
        shuiguolihe.setCataname("进口水果");
        Product p1=new Product();
        p1.setPname("智利青苹果20个装");
        p1.setPrice(new BigDecimal(108.00));
        p1.setPcount(new BigDecimal(1000));
        Product p2=new Product();
        p2.setPname("新奇士美国脐橙20个装");
        p2.setPrice(new BigDecimal(118.00));
        p2.setPcount(new BigDecimal(1000));
        Product p3=new Product();
        p3.setPname("日本陆奥苹果1个装");
        p3.setPrice(new BigDecimal(78.00));
        p3.setPcount(new BigDecimal(1000));
        List<Product> products=new ArrayList<>();
        products.add(p1);
        products.add(p2);
        products.add(p3);
        shuiguolihe.setProducts(products);
        session.save(shuiguolihe);
    }

    @Test
    public void save2()
    {
        Catalog shuiguolihe=new Catalog();
        shuiguolihe.setCataname("礼品盒子");
        Product p1=new Product();
        p1.setPname("盒子1");
        p1.setPrice(new BigDecimal(108.00));
        p1.setPcount(new BigDecimal(1000));
        Product p2=new Product();
        p2.setPname("盒子2");
        p2.setPrice(new BigDecimal(118.00));
        p2.setPcount(new BigDecimal(1000));
        Product p3=new Product();
        p3.setPname("盒子3");
        p3.setPrice(new BigDecimal(78.00));
        p3.setPcount(new BigDecimal(1000));
        List<Product> products=new ArrayList<>();
        products.add(p1);
        products.add(p2);
        products.add(p3);
        shuiguolihe.setProducts(products);
        session.save(shuiguolihe);
    }

    //当我查询到商品分类的时候 可以查询商品分类下所有商品
    @Test
    public void query()
    {
      Catalog catalog=session.get(Catalog.class,"4028c9816386ccc9016386ccd24b0000");
      List<Product> products=catalog.getProducts();
        System.out.println(products);

    }

    @Test
    public void delete()
    {
        Catalog catalog=session.get(Catalog.class,"4028c9816386c519016386c525160000");
        session.delete(catalog);

    }

    @Test
    public void update(){
        Catalog jinkoushuiguo=session.get(Catalog.class,"4028c9816386d90b016386d91d860000");
        Catalog shuiguolihe=session.get(Catalog.class,"4028c9816386ccc9016386ccd24b0000");
        List<Product> jingkoushuiguoList = jinkoushuiguo.getProducts();
        List<Product> shuiguoliheList=shuiguolihe.getProducts();
        jinkoushuiguo.setProducts(shuiguoliheList);
        shuiguolihe.setProducts(jingkoushuiguoList);
        session.update(jinkoushuiguo);
        session.update(shuiguolihe);

    }

    //将所有的水果礼盒分类删除掉 将水果礼盒的商品合并到进口水果中去
    @Test
    public void update2(){
        Catalog shuiguolihe=session.get(Catalog.class,"4028c981638705ab01638705b22a0000");
       Catalog jinkoushuiguo=session.get(Catalog.class,"4028c9816387079d01638707a3930000");
       jinkoushuiguo.getProducts().addAll(shuiguolihe.getProducts());
       shuiguolihe.getProducts().clear();
       session.update(shuiguolihe);
       session.update(jinkoushuiguo);
       session.delete(shuiguolihe);

    }

    //--把某一个商品分类下的商品全部转移到另外一个分类下 并且删除该分类
    //1.进口水果的id=4028c981638a56c601638a56eb7b0000
    //2.礼品的id=4028c981638a58ed01638a5911550000
    //大前提  目标:删除该分类  要删除存在关联关系的数据 必须先解除其关系
    @Test
    public void update3()
    {
        Catalog shuiguo = session.get(Catalog.class, "4028c981638a56c601638a56eb7b0000");
        Catalog box = session.get(Catalog.class, "4028c981638a58ed01638a5911550000");
        shuiguo.getProducts().addAll(box.getProducts()); //建立关系
        box.getProducts().clear();  //解除关系
        session.delete(box);

    }

    @Test
    public  void   get()
    {
        Product p=new Product(); //瞬态的对象
       product = session.get(Product.class, "4028c981638a58ed01638a5911b30003");
      Product  product2 = session.get(Product.class, "4028c981638a58ed01638a5911b30003");
        //从瞬态变成持久化状态 commit的时候才会同步数据表
        product.setPname(product.getPname());
      //save delete 将对象从瞬态 变成 持久化状态
        //做修改的动作 可以不需要 做session.update() 比较累赘
        //session.save();
        //session.delete();
}


    @After
    public void end(){
        //commit只对持久化状态对象做同步
        //检查你当前的内存中的对象和数据表的数据是否是一致的 如果不一致 则自动做操作
        session.getTransaction().commit();
        //对象依然存在在内存中  对象属于游离状态 操作 数据的同步的操作
        product.setPname("小刘的礼盒");
        session.close();
        sessionFactory.close();

    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.oracle</groupId>
  <artifactId>One2Many</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>One2Many Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
    </dependency>
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-core</artifactId>
      <version>5.1.0.Final</version>
    </dependency>
    <dependency>
      <groupId>com.oracle</groupId>
      <artifactId>ojdbc6</artifactId>
      <version>11.2.0.3</version>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.38</version>
    </dependency>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.16.18</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>One2Many</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.7.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.20.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
  <session-factory>
    <property name="connection.driver_class">oracle.jdbc.OracleDriver</property>
    <property name="connection.url">jdbc:oracle:thin:@10.10.44.161:1521:ORCL</property>
    <property name="connection.username">javazhao</property>
    <property name="connection.password">123456</property>
    <property name="show_sql">true</property>
    <property name="format_sql">true</property>
    <!-- DB schema will be updated if needed -->
    <property name="hbm2ddl.auto">update</property>
    <mapping class="com.oracle.bean.Product"></mapping>
    <mapping class="com.oracle.bean.Catalog"></mapping>
  </session-factory>
</hibernate-configuration>

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