Hibernate学习1 - 入门基本使用、一对多映射、多对一映射、多对多映射的使用

转x33g5p2x  于2022-06-27 转载在 其他  
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概述 = Hibernate实现JPA规范

使用 === 注意测试懒加载时别DeBug模式 = 因为Debug会调用对象内懒加载的属性从而发送了SQL

基本使用 ===

pom.xml

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <project xmlns="http://maven.apache.org/POM/4.0.0"
  3.          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4.          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  5.     <modelVersion>4.0.0</modelVersion>
  7.     <groupId>top.linruchang</groupId>
  8.     <artifactId>HibernateDemo</artifactId>
  9.     <version>1.0-SNAPSHOT</version>
  11.     <properties>
  12.         <maven.compiler.source>8</maven.compiler.source>
  13.         <maven.compiler.target>8</maven.compiler.target>
  14.     </properties>
  16.     <dependencies>
  17.         <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
  18.         <dependency>
  19.             <groupId>org.projectlombok</groupId>
  20.             <artifactId>lombok</artifactId>
  21.             <version>1.18.20</version>
  22.             <scope>provided</scope>
  23.         </dependency>
  25.         <!-- https://mvnrepository.com/artifact/cn.hutool/hutool-all -->
  26.         <dependency>
  27.             <groupId>cn.hutool</groupId>
  28.             <artifactId>hutool-all</artifactId>
  29.             <version>5.6.3</version>
  30.         </dependency>
  32.         <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
  33.         <dependency>
  34.             <groupId>mysql</groupId>
  35.             <artifactId>mysql-connector-java</artifactId>
  36.             <version>8.0.23</version>
  37.         </dependency>
  39.         <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
  40.         <dependency>
  41.             <groupId>org.hibernate</groupId>
  42.             <artifactId>hibernate-core</artifactId>
  43.             <version>6.0.0.Alpha7</version>
  44.         </dependency>
  46.         <!-- https://mvnrepository.com/artifact/junit/junit -->
  47.         <dependency>
  48.             <groupId>junit</groupId>
  49.             <artifactId>junit</artifactId>
  50.             <version>4.13.2</version>
  51.         </dependency>
  53.     </dependencies>
  55.     <build>
  56.         <!--特别注意：如果你是把Article.hbm.xml这些映射文件放到src下的beanentity目录，则需要定义这里，像我一样放到resources也不需要设置这一段-->
  57.         <resources>
  58.             <resource>
  59.                 <directory>src/main/java</directory>
  60.                 <includes>
  61.                     <include>**/*.xml</include>
  62.                 </includes>
  63.                 <filtering>false</filtering>
  64.             </resource>
  65.         </resources>
  66.     </build>
  67. </project>

hibernate.cfg.xml

  1. <?xml version='1.0' encoding='utf-8'?>
  2. <!DOCTYPE hibernate-configuration PUBLIC
  3.         "-//Hibernate/Hibernate Configuration DTD//EN"
  4.         "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
  6. <hibernate-configuration>
  8.     <!-- 以/jndi/name绑定到JNDI的SessionFactory实例 -->
  9.     <!--<session-factory name="java:hibernate/SessionFactory">-->
  10.     <session-factory >
  12.         <!--     ===============数据源配置属性===============     -->
  13.         <property name="connection.driver_class">com.mysql.cj.jdbc.Driver</property>
  14.         <property name="connection.username">root</property>
  15.         <property name="connection.password">root</property>
  16.         <property name="connection.url">jdbc:mysql://localhost:3306/test?useSSL=false&amp;characterEncoding=UTF-8&amp;serverTimezone=Asia/Shanghai</property>
  18.         <!--     ===============C3P0连接池配置===============    -->
  19.         <!-- 连接池中最少有多少个数据库连接 -->
  20.         <property name="hibernate.c3p0.min_size">30</property>
  21.         <!-- 连接池中允许的最大数据库连接数 -->
  22.         <property name="hibernate.c3p0.max_size">30</property>
  23.         <!-- 最大的PreparedStatement的数量 -->
  24.         <property name="hibernate.c3p0.max_statements">10</property>
  25.         <!--数据库连接不够时，每次增加的连接数-->
  26.         <property name="hibernate.c3p0.acquire_increment">10</property>
  27.         <!--数据库连接不用时，多长时间释放该连接，以秒为单位-->
  28.         <property name="hibernate.c3p0.idle_test_period">10000</property>
  29.         <!--连接处理最大时间，如果超过这个时间,会抛出异常，以豪秒为单位-->
  30.         <property name="hibernate.c3p0.timeout">5000</property>
  32.         <!--     ===============数据库方言===============    -->
  33.         <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
  35.         <!--     ===============功能===============    -->
  36.         <!--打印SQL-->
  37.         <property name="show_sql">true</property>
  38.         <!--格式化SQL语句-->
  39.         <property name="format_sql">true</property>
  40.         <!--是否自动生成数据库-->
  41.         <property name="hibernate.hbm2ddl.auto"/>
  43.         <!--     ===============注册实体关系映射文件===============    -->
  44.         <mapping resource="mapping/SysUser.hbm.xml"></mapping>
  45.         <mapping resource="mapping/Article.hbm.xml"></mapping>
  46.         <!--将此映射文件直接放到跟Bean的源码目录包下的写法-->
  47.         <!--<mapping resource="top/linruchang/entity/SysUser.hbm.xml"></mapping>-->
  48.         <!--<mapping resource="top/linruchang/entity/Article.hbm.xml"></mapping>-->
  50.     </session-factory>
  52. </hibernate-configuration>

Article.hbm.xml

  1. <?xml version="1.0"?>
  2. <!DOCTYPE hibernate-mapping PUBLIC
  3.         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  4.         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  6. <hibernate-mapping>
  7.     <class name="top.linruchang.entity.Article" table="article">
  8.         <id name="id" type="java.lang.String">
  9.             <column name="id" ></column>
  10.             <!--插入时，如果你没有设置ID，会帮你自动添加ID-->
  11.             <generator class="uuid"></generator>
  12.         </id>
  14.         <property name="title" type="java.lang.String">
  15.             <column name="title"></column>
  16.         </property>
  18.         <property name="content" type="java.lang.String">
  19.             <column name="content"></column>
  20.         </property>
  22.         <property name="likeNum" type="java.lang.Integer">
  23.             <column name="like_num"></column>
  24.         </property>
  26.     </class>
  27. </hibernate-mapping>

Article.java

  1. @Data
  2. @NoArgsConstructor
  3. @AllArgsConstructor
  4. @Builder
  5. @Accessors(chain = true)
  6. public class Article extends BaseEntity {
  8.     private static final long serialVersionUID = -4714261187453073302L;
  10.     private SysUser sysUser;
  12.     /** 文章标题 */
  13.     private String title;
  15.     /** 文章内容 */
  16.     private String content;
  18.     private String abbreviationContent;
  20.     /** 文章被查看次数 */
  21.     private Integer checkNum;
  23.     /** 当前文章被点赞数 */
  24.     private Integer likeNum;
  26.     /** 当前文章不喜欢数 */
  27.     private Integer notLikeNum;
  29.     /** 文章是否违规：0未违规 1违规 - 违规不可显示 */
  30.     private Integer isViolation;
  32.     /** 创建者 - 冗余字段 - user表的nickName */
  33.     private String createBy;
  35.     /**列表文章的图片显示 - 如果指定则使用指定的图片（功能未做），没有指定则使用文章第一张图片，在没有则使用文章中有图标则使用目录分裂的图片*/
  36.     private String imgUrl;
  38.     /**文章内部图片*/
  39.     private String imgUrls;
  41.     /**文章内容类型：1富文本 2Markdown 3留空*/
  42.     private String type;
  44.     /**文章状态；-1违规 0草稿 1发布且公开  2发布且私密*/
  45.     private String status;
  47. }

MyTest.java

  1. public class MyTest {
  3.     public static void main(String[] args) {
  5.         Configuration configure = new Configuration().configure();
  7.         //获取sessionFactory
  8.         SessionFactory sessionFactory = configure.buildSessionFactory();
  9.         //获取数据库连接session
  10.         Session session = sessionFactory.openSession();
  12.         Article article = session.find(Article.class, "0f67d9f1953c7ab6036ece36cb5e1133");
  13.         System.out.println(article);
  15.         Article saveArticle = Article.builder()
  16.                 .checkNum(20)
  17.                 .likeNum(100)
  18.                 .content("你好")
  19.                 .title("爱你似懂非懂舒服的").build();
  20.         saveArticle.setId(UUID.fastUUID().toString(true));
  21.         Object save = session.save(saveArticle);
  22.         System.out.println(save);
  23.         // System.out.println(saveArticle.getId());
  24.         // System.out.println(save);
  26.         //特别注意：这里必须手动提交事务
  27.         session.beginTransaction().commit();
  28.         session.close();
  29.     }
  31. }

一对多映射

一个用户对应多篇文章

 
SysUser.java

  1. @Data
  2. @NoArgsConstructor
  3. @AllArgsConstructor
  4. @Builder
  5. @Accessors(chain = true)
  6. public class SysUser extends BaseEntity {
  7.     private static final long serialVersionUID = 2095940921263481761L;
  9.     Set<Article> articles;
  11.     /** 用户昵称 - 如果没有设置昵称直接使用账户名显示 */
  12.     private String nickName;
  14.     /** 头像图片地址 */
  15.     private String headUrl;
  17.     /** 账户 */
  18.     private String loginName;
  20.     /** 密码 */
  21.     private String password;
  23.     /** 手机号 */
  24.     private String phoneNumber;
  26.     /** 邮箱 */
  27.     private String email;
  29.     /** 性别 */
  30.     private Integer gender;
  32.     /** 个性签名 */
  33.     private String personalMotto;
  35.     /** 最近登录时间 - 格式 - yyyyMMddHHmmss */
  36.     private String lastLoginTime;
  38.     /** 登录状态：0未登录 1单设备登陆  2多设备登陆 */
  39.     private Integer loginStatus;
  41.     /** 账户禁用状态：0账户可使用  1账户不可使用（封号） */
  42.     private Integer disabledStatus;
  44. }

 
Article.java

  1. @Data
  2. @NoArgsConstructor
  3. @AllArgsConstructor
  4. @Builder
  5. @Accessors(chain = true)
  6. public class Article extends BaseEntity {
  8.     private static final long serialVersionUID = -4714261187453073302L;
  10.     private SysUser sysUser;
  12.     private String userId;
  14.     /** 文章标题 */
  15.     private String title;
  17.     /** 文章内容 */
  18.     private String content;
  20.     private String abbreviationContent;
  22.     /** 文章被查看次数 */
  23.     private Integer checkNum;
  25.     /** 当前文章被点赞数 */
  26.     private Integer likeNum;
  28.     /** 当前文章不喜欢数 */
  29.     private Integer notLikeNum;
  31.     /** 文章是否违规：0未违规 1违规 - 违规不可显示 */
  32.     private Integer isViolation;
  34.     /** 创建者 - 冗余字段 - user表的nickName */
  35.     private String createBy;
  37.     /**列表文章的图片显示 - 如果指定则使用指定的图片（功能未做），没有指定则使用文章第一张图片，在没有则使用文章中有图标则使用目录分裂的图片*/
  38.     private String imgUrl;
  40.     /**文章内部图片*/
  41.     private String imgUrls;
  43.     /**文章内容类型：1富文本 2Markdown 3留空*/
  44.     private String type;
  46.     /**文章状态；-1违规 0草稿 1发布且公开  2发布且私密*/
  47.     private String status;
  49. }

 
SysUser.hbm.xml

  1. <?xml version="1.0"?>
  2. <!DOCTYPE hibernate-mapping PUBLIC
  3.         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  4.         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  6. <hibernate-mapping>
  7.     <class name="top.linruchang.entity.SysUser" table="sys_user">
  8.         <id name="id" type="java.lang.String">
  9.             <column name="id"></column>
  10.             <!--插入时，如果你没有设置ID，会帮你自动添加ID-->
  11.             <generator class="uuid"></generator>
  12.         </id>
  14.         <property name="headUrl" type="java.lang.String">
  15.             <column name="head_url" ></column>
  16.         </property>
  18.         <property name="loginName" type="java.lang.String">
  19.             <column name="login_name" ></column>
  20.         </property>
  22.         <set name="articles" table="article">
  23.             <!-- Article表的外键列名-->
  24.             <key column="user_id"></key>
  25.             <one-to-many class="top.linruchang.entity.Article"></one-to-many>
  26.         </set>
  28.     </class>
  29. </hibernate-mapping>

 
Article.hbm.xml

  1. <?xml version="1.0"?>
  2. <!DOCTYPE hibernate-mapping PUBLIC
  3.         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  4.         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  6. <hibernate-mapping>
  7.     <class name="top.linruchang.entity.Article" table="article">
  8.         <id name="id" type="java.lang.String">
  9.             <column name="id" ></column>
  10.             <!--插入时，如果你没有设置ID，会帮你自动添加ID-->
  11.             <generator class="uuid"></generator>
  12.         </id>
  13.         
  14.         <!--逻辑外键，即sysUser表的主键ID-->
  15.         <property name="userId" type="java.lang.String">
  16.             <column name="user_id"></column>
  17.         </property>
  19.         <property name="title" type="java.lang.String">
  20.             <column name="title"></column>
  21.         </property>
  23.         <property name="content" type="java.lang.String">
  24.             <column name="content"></column>
  25.         </property>
  27.         <property name="likeNum" type="java.lang.Integer">
  28.             <column name="like_num"></column>
  29.         </property>
  31.         <!--<property name="sysUser" type="top.linruchang.entity.SysUser">-->
  32.         <!--    <column name="like_num"></column>-->
  33.         <!--</property>-->
  35.     </class>
  36. </hibernate-mapping>

 
Article.hbm.xml

  1. @Test
  2.     public void test1() {
  4.         Configuration configure = new Configuration().configure();
  6.         // 获取sessionFactory
  7.         SessionFactory sessionFactory = configure.buildSessionFactory();
  8.         // 获取数据库连接session
  9.         Session session = sessionFactory.openSession();
  10.         SysUser sysUser = session.find(SysUser.class, "6d72c93aa292cf2ca2e789919a5e7bdc");
  11.         System.out.println(sysUser);
  13.     }

多对一映射

 
MyOrder.java

  1. @Data
  2. @ToString(callSuper = true)
  3. public class MyOrder extends BaseEntity{
  5.     MyUser myUser;
  7.     String name;
  8.     String money;
  10. }

 
MyUser.java

  1. @Data
  2. @ToString(callSuper = true)
  3. public class MyUser extends BaseEntity{
  5.     String name;
  6. }

 
MyOrder.hbm.xml

  1. <?xml version="1.0"?>
  2. <!DOCTYPE hibernate-mapping PUBLIC
  3.         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  4.         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  6. <hibernate-mapping>
  7.     <class name="top.linruchang.entity.MyOrder" table="my_order">
  8.         <id name="id" type="java.lang.String">
  9.             <column name="id"></column>
  10.             <!--插入时，如果你没有设置ID，会帮你自动添加ID-->
  11.             <generator class="uuid"></generator>
  12.         </id>
  14.         <property name="name" type="java.lang.String">
  15.             <column name="name"></column>
  16.         </property>
  18.         <property name="money" type="java.lang.String">
  19.             <column name="money"></column>
  20.         </property>
  22.         <many-to-one name="myUser" column="user_id" class="top.linruchang.entity.MyUser"></many-to-one>
  24.     </class>
  25. </hibernate-mapping>

 
MyUser.hbm.xml

  1. <?xml version="1.0"?>
  2. <!DOCTYPE hibernate-mapping PUBLIC
  3.         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  4.         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  6. <hibernate-mapping>
  7.     <class name="top.linruchang.entity.MyUser" table="my_user">
  8.         <id name="id" type="java.lang.String">
  9.             <column name="id"></column>
  10.             <!--插入时，如果你没有设置ID，会帮你自动添加ID-->
  11.             <generator class="uuid"></generator>
  12.         </id>
  14.         <property name="name" type="java.lang.String">
  15.             <column name="name"></column>
  16.         </property>
  18.     </class>
  19. </hibernate-mapping>

查询

 
MyTest.java

  1. public class MyTest {
  3.     @Test
  4.     public void test3() {
  6.         Configuration configure = new Configuration().configure();
  8.         //获取sessionFactory
  9.         SessionFactory sessionFactory = configure.buildSessionFactory();
  10.         //获取数据库连接session
  11.         Session session = sessionFactory.openSession();
  12.         MyOrder myOrder = session.find(MyOrder.class, "9ac327eda05d11ebb7a6b42e99ea3e61");
  14.         MyUser myUser = myOrder.getMyUser();
  15.         System.out.println(myOrder);
  17.     }
  18. }

插入

  1. @Test
  2.     public void test4() {
  4.         Configuration configure = new Configuration().configure();
  6.         //获取sessionFactory
  7.         SessionFactory sessionFactory = configure.buildSessionFactory();
  8.         //获取数据库连接session
  9.         Session session = sessionFactory.openSession();
  10.         Transaction transaction = session.beginTransaction();
  12.         MyOrder myOrder = new MyOrder();
  13.         myOrder.setId(UUID.fastUUID().toString(true));
  14.         myOrder.setName("热狗");
  15.         myOrder.setMoney("5");
  17.         MyUser myUser = new MyUser();
  18.         myUser.setId(UUID.fastUUID().toString(true));
  19.         myUser.setName("立法的方式地方=====");
  20.         myOrder.setMyUser(myUser);
  21.         
  22.         //先插入外键表的数据
  23.         Object insertUserId = session.save(myUser);
  24.         System.out.println(insertUserId);
  25.         //随后在插入主表的数据
  26.         Object insertOrderId = session.save(myOrder);
  27.         System.out.println(insertOrderId);
  29.         transaction.commit();
  30.         session.close();
  32.     }

多对多映射 == 需要中间表

 
MyOrder2.java

  1. @Getter
  2. @Setter
  3. public class MyOrder2 extends BaseEntity{
  5.     String name;
  6.     String money;
  8.     Set<MyUser2> myUser2;
  10.     @Override
  11.     public String toString() {
  12.         return "MyOrder2{" +
  13.                 "id='" + getId() + '\'' +
  14.                 "name='" + name + '\'' +
  15.                 ", money='" + money + '\'' +
  16.                 '}';
  17.     }
  18. }

 
MyUser2.java

  1. @Getter
  2. @Setter
  3. public class MyUser2 extends BaseEntity{
  5.     String name;
  7.     Set<MyOrder2> myOrder2;
  9.     @Override
  10.     public String toString() {
  11.         return "MyUser2{" +
  12.                 "id='" + getId() + '\'' +
  13.                 "name='" + name + '\'' +
  14.                 '}';
  15.     }
  16. }

 
UserOrderRel.java

  1. @Getter
  2. @Setter
  3. public class UserOrderRel extends BaseEntity{
  4.     String myUserId;
  5.     String myOrderId;
  6. }

 
MyOrder2.hbm.xml

  1. <?xml version="1.0"?>
  2. <!DOCTYPE hibernate-mapping PUBLIC
  3.         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  4.         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  6. <hibernate-mapping>
  7.     <class name="top.linruchang.entity.MyOrder2" table="my_order">
  8.         <id name="id" type="java.lang.String">
  9.             <column name="id"></column>
  10.             <!--插入时，如果你没有设置ID，会帮你自动添加ID-->
  11.             <generator class="uuid"></generator>
  12.         </id>
  14.         <property name="name" type="java.lang.String">
  15.             <column name="name"></column>
  16.         </property>
  18.         <property name="money" type="java.lang.String">
  19.             <column name="money"></column>
  20.         </property>
  22.         <set name="myUser2" table="user_order_rel">
  23.             <key column="my_order_id" ></key>
  24.             <many-to-many column="my_user_id" class="top.linruchang.entity.MyUser2"></many-to-many>
  25.         </set>
  28.     </class>
  29. </hibernate-mapping>

 
MyUser2.hbm.xml

  1. <?xml version="1.0"?>
  2. <!DOCTYPE hibernate-mapping PUBLIC
  3.         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  4.         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  6. <hibernate-mapping>
  7.     <class name="top.linruchang.entity.MyUser2" table="my_user">
  8.         <id name="id" type="java.lang.String">
  9.             <column name="id"></column>
  10.             <!--插入时，如果你没有设置ID，会帮你自动添加ID-->
  11.             <generator class="uuid"></generator>
  12.         </id>
  14.         <property name="name" type="java.lang.String">
  15.             <column name="name"></column>
  16.         </property>
  18.         <set name="myOrder2" table="user_order_rel">
  19.             <key column="my_user_id" ></key>
  20.             <many-to-many column="my_order_id" class="top.linruchang.entity.MyOrder2"></many-to-many>
  21.         </set>
  23.     </class>
  24. </hibernate-mapping>

 
UserOrderRel.hbm.xml

  1. <?xml version="1.0"?>
  2. <!DOCTYPE hibernate-mapping PUBLIC
  3.         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  4.         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  6. <hibernate-mapping>
  7.     <class name="top.linruchang.entity.UserOrderRel" table="user_order_rel">
  8.         <id name="id" type="java.lang.String">
  9.             <column name="id"></column>
  10.             <!--插入时，如果你没有设置ID，会帮你自动添加ID-->
  11.             <generator class="uuid"></generator>
  12.         </id>
  14.         <property name="myUserId" type="java.lang.String">
  15.             <column name="my_user_id"></column>
  16.         </property>
  18.         <property name="myOrderId" type="java.lang.String">
  19.             <column name="my_order_id"></column>
  20.         </property>
  22.     </class>
  23. </hibernate-mapping>

 
MyTest.java

  1. public class MyTest {
  4.     @Test
  5.     public void test5() {
  7.         Configuration configure = new Configuration().configure();
  8.         SessionFactory sessionFactory = configure.buildSessionFactory();
  9.         Session session = sessionFactory.openSession();
  10.         MyOrder2 myOrder2 = session.find(MyOrder2.class, "4028b88178e60a910178e60a94c90001");
  11.         System.out.println(myOrder2);
  12.         System.out.println(myOrder2.getMyUser2());
  13.         session.close();
  15.     }
  18. }

版权说明 : 本文为转载文章, 版权归原作者所有 版权申明

原文链接 : https://blog.csdn.net/weixin_39651356/article/details/125328966

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