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Hibernate初學者---多對多單/雙向關聯

Hibernate 版本: v5.2.10
Eclipse版本:v4.7.1
JDK版本: v1.8
MySQL版本:v5.7

多對多單向

POJO類一

package com.bak.bum.union;

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

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import
javax.persistence.JoinColumn; import javax.persistence.JoinTable; import javax.persistence.ManyToMany; import javax.persistence.Table; @Entity @Table(name = "100_teacher") public class Teacher { private int id; private String name; Set<Students> students = new HashSet<Students>(); @Id
@GeneratedValue(strategy = GenerationType.IDENTITY) public int getId() { return id; } public String getName() { return name; } @ManyToMany @JoinTable(name = "tsTable", joinColumns = { @JoinColumn(name = "TeacherID") }, inverseJoinColumns = { @JoinColumn
(name = "StudentsID") }) public Set<Students> getStudents() { return students; } public void setId(int id) { this.id = id; } public void setName(String name) { this.name = name; } public void setStudents(Set<Students> students) { this.students = students; } }

POJO類二

package com.bak.bum.union;

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

@Entity
@Table(name="100_students")
public class Students {
    private int id;
    private String name;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

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

    public void setName(String name) {
        this.name = name;
    }

}

Junit -TEST類

package com.bak.fan.test;

import java.util.EnumSet;

import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.hibernate.tool.schema.TargetType;

public class Test {

    @org.junit.Test
    public void test() {
        ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().configure().build();
        Metadata metadata = new MetadataSources(serviceRegistry).buildMetadata();
        SchemaExport schemaExport = new SchemaExport();
        schemaExport.create(EnumSet.of(TargetType.DATABASE), metadata);


}
}

hibernate.cfg.xml

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

<!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>

        <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">shwythnn00</property>

        <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>

        <property name="show_sql">true</property>

        <property name="hibernate.format_sql">true</property>

        <property name="hibernate.hbm2ddl.auto">create</property>

        <property name=""></property>


        <mapping class="com.bak.bum.union.Teacher" />
        <mapping class="com.bak.bum.union.Students" />
    </session-factory>
</hibernate-configuration>  

輸出結果
這裡寫圖片描述

SHOW DB
這裡寫圖片描述

多對多雙向

POJO類一

package com.bak.bum.union;

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

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

@Entity
@Table(name = "200_teacher")
public class Teacher {
    private int id;
    private String name;
    Set<Students> students = new HashSet<Students>();

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    @ManyToMany
    @JoinTable(name = "tsTable", joinColumns = { @JoinColumn(name = "TeacherID") }, inverseJoinColumns = {
            @JoinColumn(name = "StudentsID") })
    public Set<Students> getStudents() {
        return students;
    }

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

    public void setName(String name) {
        this.name = name;
    }

    public void setStudents(Set<Students> students) {
        this.students = students;
    }

}

POJO類二

package com.bak.bum.union;

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

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

@Entity
@Table(name = "200_students")
public class Students {

    private int id;
    private String name;
    private Set<Teacher> teacher = new HashSet<Teacher>();

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    @ManyToMany(mappedBy="students")
    public Set<Teacher> getTeacher() {
        return teacher;
    }

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

    public void setName(String name) {
        this.name = name;
    }

    public void setTeacher(Set<Teacher> teacher) {
        this.teacher = teacher;
    }

}

Junit-Test類

package com.bak.fan.test;

import java.util.EnumSet;

import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.hibernate.tool.schema.TargetType;

public class Test {

    @org.junit.Test
    public void test() {
        ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().configure().build();
        Metadata metadata = new MetadataSources(serviceRegistry).buildMetadata();
        SchemaExport schemaExport = new SchemaExport();
        schemaExport.create(EnumSet.of(TargetType.DATABASE), metadata);


}
}

hibernate.cfg.xml

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

<!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>

        <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">shwythnn00</property>

        <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>

        <property name="show_sql">true</property>

        <property name="hibernate.format_sql">true</property>

        <property name="hibernate.hbm2ddl.auto">create</property>

        <property name=""></property>


        <mapping class="com.bak.bum.union.Teacher" />
        <mapping class="com.bak.bum.union.Students" />
    </session-factory>
</hibernate-configuration>  

輸出結果
這裡寫圖片描述

SHOW DB;
這裡寫圖片描述

JAR
這裡寫圖片描述
這裡寫圖片描述

多對多單雙向關聯,對資料表無影響。只是在程式上可以互相訪問。