Hibernate学习笔记3.3（Hibernate组建映射2）

多对多

相当于一个老师可以教多个学生，一个学生也可以有多个老师

数据表中都是再设计一个表寸相关的id

1.多对多单向

1annotation

Student.java

package com.bjsxt.hibernate;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
public class Student {
    private int id;
    private String name;
    
    @Id
    @GeneratedValue
    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;
    }
}

teacher.java

package com.bjsxt.hibernate;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
public class Teacher {
    private int id;
    private String name;
    private Set<Student> students = new HashSet<Student>();
    @Id
    @GeneratedValue
    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;
    }
    @ManyToMany
    @JoinTable(name="t_s",
        joinColumns={@JoinColumn(name="teacher_id")},    //自己这个类的外键id
        inverseJoinColumns={@JoinColumn(name="student_id")}   //对方那张表的外键id
        )
    public Set<Student> getStudents() {
        return students;
    }
    public void setStudents(Set<Student> students) {
        this.students = students;
    }
}

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

         
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost/hibernate</property>
        <property name="connection.username">root</property>
        <property name="connection.password">bjsxt</property>
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
       <!--
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:SXT</property>
        <property name="connection.username">scott</property>
        <property name="connection.password">tiger</property>
          <property name="dialect">org.hibernate.dialect.OracleDialect</property>
       -->

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>

        <!-- Drop and re-create the database schema on startup
        <property name="hbm2ddl.auto">update</property>
         -->
        
        <mapping class="com.bjsxt.hibernate.Teacher"/>
        <mapping class="com.bjsxt.hibernate.Student"/>
        
        
        <!--  
         <mapping resource="com/bjsxt/hibernate/Teacher.hbm.xml"/>
         <mapping resource="com/bjsxt/hibernate/Student.hbm.xml"/>
          -->
    </session-factory>

</hibernate-configuration>

测试代码

package com.bjsxt.hibernate;

import java.util.Date;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class HibernateORMappingTest {
    private static SessionFactory sessionFactory;
    
    //@BeforeClass
    public static void beforeClass() {
            sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
    }
    //@AfterClass
    public static void afterClass() {
        sessionFactory.close();
    }
    
    
    
    @Test
    public void testSchemaExport() {
        new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
    }
    
    public static void main(String[] args) {
        beforeClass();
    }
}

2.xml

student.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
    <class name="com.bjsxt.hibernate.Student">
        <id name="id">
            <generator class="native"></generator>
        </id>
        
        <property name="name"></property>
    </class>
    
</hibernate-mapping>

teacher.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
    <class name="com.bjsxt.hibernate.Student">
        <id name="id">
            <generator class="native"></generator>
        </id>
        
        <property name="name"></property>
    </class>
    
</hibernate-mapping>

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

         
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost/hibernate</property>
        <property name="connection.username">root</property>
        <property name="connection.password">bjsxt</property>
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
       <!--
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:SXT</property>
        <property name="connection.username">scott</property>
        <property name="connection.password">tiger</property>
          <property name="dialect">org.hibernate.dialect.OracleDialect</property>
       -->

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>

        <!-- Drop and re-create the database schema on startup
        <property name="hbm2ddl.auto">update</property>
         -->
        <!--  
        <mapping class="com.bjsxt.hibernate.Teacher"/>
        <mapping class="com.bjsxt.hibernate.Student"/>
         -->
        
        
         <mapping resource="com/bjsxt/hibernate/Teacher.hbm.xml"/>
         <mapping resource="com/bjsxt/hibernate/Student.hbm.xml"/>
         
    </session-factory>

</hibernate-configuration>

 多对多双向关联

1.annotation

student.java

package com.bjsxt.hibernate;

import java.util.HashSet;
import java.util.Set;

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

@Entity
public class Student {
    private int id;
    private String name;
    private Set<Teacher> teachers = new HashSet<Teacher>();
    @ManyToMany(mappedBy="students")
    public Set<Teacher> getTeachers() {
        return teachers;
    }
    public void setTeachers(Set<Teacher> teachers) {
        this.teachers = teachers;
    }
    @Id
    @GeneratedValue
    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;
    }
}

Teacher.java

package com.bjsxt.hibernate;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
public class Teacher {
    private int id;
    private String name;
    private Set<Student> students = new HashSet<Student>();
    @Id
    @GeneratedValue
    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;
    }
    @ManyToMany
    @JoinTable(name="t_s",
        joinColumns={@JoinColumn(name="teacher_id")},
        inverseJoinColumns={@JoinColumn(name="student_id")}
        )
    public Set<Student> getStudents() {
        return students;
    }
    public void setStudents(Set<Student> students) {
        this.students = students;
    }
}

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

         
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost/hibernate</property>
        <property name="connection.username">root</property>
        <property name="connection.password">bjsxt</property>
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
       <!--
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:SXT</property>
        <property name="connection.username">scott</property>
        <property name="connection.password">tiger</property>
          <property name="dialect">org.hibernate.dialect.OracleDialect</property>
       -->

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>

        <!-- Drop and re-create the database schema on startup
        <property name="hbm2ddl.auto">update</property>
         -->
      
       
          <mapping class="com.bjsxt.hibernate.Teacher"/>
        <mapping class="com.bjsxt.hibernate.Student"/>
  <!--  
<mapping resource="com/bjsxt/hibernate/Teacher.hbm.xml"/> <mapping resource="com/bjsxt/hibernate/Student.hbm.xml"/>
 -->
        
</session-factory> </hibernate-configuration>

test.java

package com.bjsxt.hibernate;

import java.util.Date;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class HibernateORMappingTest {
    private static SessionFactory sessionFactory;
    
    //@BeforeClass
    public static void beforeClass() {
            sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
    }
    //@AfterClass
    public static void afterClass() {
        sessionFactory.close();
    }
    
    
    
    @Test
    public void testSchemaExport() {
        new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
    }
    
    public static void main(String[] args) {
        beforeClass();
    }
}

2。xml

Student.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
    <class name="com.bjsxt.hibernate.Student">
        <id name="id">
            <generator class="native"></generator>
        </id>
        
        <property name="name"></property>
        <set name="teachers" table="t_s">
            <key column="student_id"></key>
            <many-to-many class="com.bjsxt.hibernate.Teacher" column="teacher_id"/>
        </set>
    </class>
    
</hibernate-mapping>

Teacher.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
    <class name="com.bjsxt.hibernate.Teacher">
        <id name="id">
            <generator class="native"></generator>
        </id>
        
        <property name="name"></property>
        <set name="students" table="t_s">
            <key column="teacher_id"></key>
            <many-to-many class="com.bjsxt.hibernate.Student" column="student_id"/>
        </set>
    </class>
    
</hibernate-mapping>

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

         
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost/hibernate</property>
        <property name="connection.username">root</property>
        <property name="connection.password">bjsxt</property>
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
       <!--
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:SXT</property>
        <property name="connection.username">scott</property>
        <property name="connection.password">tiger</property>
          <property name="dialect">org.hibernate.dialect.OracleDialect</property>
       -->

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>

        <!-- Drop and re-create the database schema on startup
        <property name="hbm2ddl.auto">update</property>
         -->
        <!--  
       
          <mapping class="com.bjsxt.hibernate.Teacher"/>
        <mapping class="com.bjsxt.hibernate.Student"/>
        
         -->
        
        
        <mapping resource="com/bjsxt/hibernate/Teacher.hbm.xml"/>
         <mapping resource="com/bjsxt/hibernate/Student.hbm.xml"/>
    </session-factory>

</hibernate-configuration>

test一致

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原文地址：https://www.cnblogs.com/frankzone/p/9449823.html