1、Annotation 注解版
1.1、应用场景（Student-Teacher）：当学生知道有哪些老师教，但是老师不知道自己教哪些学生时，可用单向关联的多对多模式
1.2、创建Teacher类和Student类
1 package com.shore.model;
2
3 import javax.persistence.Entity;
4 import javax.persistence.GeneratedValue;
5 import javax.persistence.GenerationType;
6 import javax.persistence.Id;
7 import javax.persistence.Table;
8
9 /**
10 * @author DSHORE/2019-9-22
11 * 多对多，单向关联（注解版）
12 */
13 @Entity
14 @Table(name="anno_teacher")
15 public class Teacher {
16 private Integer id;
17 private String name;
18 private Integer age;
19
20 @Id
21 @GeneratedValue(strategy=GenerationType.IDENTITY)
22 public Integer getId() {
23 return id;
24 }
25 public void setId(Integer id) {
26 this.id = id;
27 }
28 public String getName() {
29 return name;
30 }
31 public void setName(String name) {
32 this.name = name;
33 }
34 public Integer getAge() {
35 return age;
36 }
37 public void setAge(Integer age) {
38 this.age = age;
39 }
40 }
Student类
1 package com.shore.model;
2
3 import java.util.HashSet;
4 import java.util.Set;
5
6 import javax.persistence.Entity;
7 import javax.persistence.GeneratedValue;
8 import javax.persistence.GenerationType;
9 import javax.persistence.Id;
10 import javax.persistence.JoinColumn;
11 import javax.persistence.JoinTable;
12 import javax.persistence.ManyToMany;
13 import javax.persistence.Table;
14
15 /**
16 * @author DSHORE/2019-9-22
17 * 多对一，单向关联（注解版）
18 */
19 @Entity
20 @Table(name="anno_student")
21 public class Student {
22 private Integer id;
23 private String number;
24 private Float sum;
25 private Set<Teacher> teachers = new HashSet<Teacher>();
26
27 @Id
28 @GeneratedValue(strategy=GenerationType.IDENTITY)
29 public Integer getId() {
30 return id;
31 }
32 public void setId(Integer id) {
33 this.id = id;
34 }
35 public String getNumber() {
36 return number;
37 }
38 public void setNumber(String number) {
39 this.number = number;
40 }
41 public Float getSum() {
42 return sum;
43 }
44 public void setSum(Float sum) {
45 this.sum = sum;
46 }
47
48 /**
49 * name：中间表的表名
50 * joinColumns：当前对象所对应的id
51 * inverseJoinColumns：对方对象所对应的id
52 */
53 @ManyToMany
54 @JoinTable(name="anno_student_teacher",
55 [email protected](name="student_id"),
56 [email protected](name="teacher_id"))
57 public Set<Teacher> getTeachers() {
58 return teachers;
59 }
60 public void setTeachers(Set<Teacher> teachers) {
61 this.teachers = teachers;
62 }
63 }
1.3、创建hibernate.cfg.xml核心配置文件
1 <?xml version=‘1.0‘ encoding=‘utf-8‘?> 2 <!DOCTYPE hibernate-configuration PUBLIC 3 "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 4 "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 5 6 <hibernate-configuration> 7 <session-factory> 8 <!-- Database connection settings --> 9 <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 10 <property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property> 11 <property name="connection.username">root</property> 12 <property name="connection.password">123456</property> 13 14 <property name="dialect">org.hibernate.dialect.MySQLDialect</property> 15 <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> 16 <property name="show_sql">true</property> 17 <property name="hbm2ddl.auto">create</property> 18 19 <mapping class="com.shore.model.Teacher" /> 20 <mapping class="com.shore.model.Student" /> 21 </session-factory> 22 </hibernate-configuration>
1.4、开始测试
1 package com.shore.test;
2
3 import org.hibernate.cfg.AnnotationConfiguration;
4 import org.hibernate.tool.hbm2ddl.SchemaExport;
5 import org.junit.Test;
6
7 /**
8 * @author DSHORE/2019-9-22
9 *
10 */
11 public class AnnotationTest {
12 @Test
13 public void test() {//简单测试，只创建表，不插入数据
14 new SchemaExport(new AnnotationConfiguration().configure()).create(
15 false, true);
16 }
17 }
测试结果图：
2、XML版 的实现
2.1、创建Teacher类和Student类
1 package com.shore.model;
2
3 /**
4 * @author DSHORE/2019-9-22
5 * 多对多，单向关联（xml版）
6 */
7 public class Teacher {
8 private Integer id;
9 private String name;
10 private Integer age;
11
12 public Integer getId() {
13 return id;
14 }
15 public void setId(Integer id) {
16 this.id = id;
17 }
18 public String getName() {
19 return name;
20 }
21 public void setName(String name) {
22 this.name = name;
23 }
24 public Integer getAge() {
25 return age;
26 }
27 public void setAge(Integer age) {
28 this.age = age;
29 }
30 }
Student类
1 package com.shore.model;
2
3 import java.util.HashSet;
4 import java.util.Set;
5
6 /**
7 * @author DSHORE/2019-9-22
8 * 多对一，单向关联（xml版）
9 */
10 public class Student {
11 private Integer id;
12 private String number;
13 private Float sum;
14 private Set<Teacher> teachers = new HashSet<Teacher>();
15
16 public Integer getId() {
17 return id;
18 }
19 public void setId(Integer id) {
20 this.id = id;
21 }
22 public String getNumber() {
23 return number;
24 }
25 public void setNumber(String number) {
26 this.number = number;
27 }
28 public Float getSum() {
29 return sum;
30 }
31 public void setSum(Float sum) {
32 this.sum = sum;
33 }
34 public Set<Teacher> getTeachers() {
35 return teachers;
36 }
37 public void setTeachers(Set<Teacher> teachers) {
38 this.teachers = teachers;
39 }
40 }
2.2、创建 Teacher.hbm.xml 配置文件和 Student.hbm.xml 配置文件
1 <?xml version="1.0"?> 2 <!DOCTYPE hibernate-mapping PUBLIC 3 "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 4 "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 5 6 <hibernate-mapping package="com.shore.model"> 7 <class name="Teacher" table="xml_teacher"> 8 <id name="id"> 9 <generator class="native"/> 10 </id> 11 <property name="name" type="java.lang.String"/> 12 <property name="age" type="java.lang.Integer"/> 13 </class> 14 </hibernate-mapping>
Student.hbm.xml 配置文件
1 <?xml version="1.0"?> 2 <!DOCTYPE hibernate-mapping PUBLIC 3 "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 4 "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 5 6 <hibernate-mapping package="com.shore.model"> 7 <class name="Student" table="xml_student"> 8 <id name="id"> 9 <generator class="native"/> 10 </id> 11 <property name="number" type="java.lang.String"/> 12 <property name="sum" type="java.lang.Float"/> 13 14 <set name="teachers" table="xml_student_teacher"> 15 <key column="student_id"/> <!-- 当前对象所对应的id --> 16 <many-to-many class="com.shore.model.Teacher" column="teacher_id"/> <!-- 对方对象所对应的id --> 17 </set> 18 </class> 19 </hibernate-mapping>
2.3、创建hibernate.cfg.xml 核心配置文件
1 <?xml version=‘1.0‘ encoding=‘utf-8‘?> 2 <!DOCTYPE hibernate-configuration PUBLIC 3 "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 4 "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 5 6 <hibernate-configuration> 7 <session-factory> 8 <!-- Database connection settings --> 9 <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 10 <property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property> 11 <property name="connection.username">root</property> 12 <property name="connection.password">123456</property> 13 14 <property name="dialect">org.hibernate.dialect.MySQLDialect</property> 15 <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> 16 <property name="show_sql">true</property> 17 <property name="hbm2ddl.auto">create</property> 18 19 <!-- <mapping class="com.shore.model.Teacher" /> 20 <mapping class="com.shore.model.Student" /> --> 21 <mapping resource="com/shore/model/Teacher.hbm.xml" /> 22 <mapping resource="com/shore/model/Student.hbm.xml" /> 23 </session-factory> 24 </hibernate-configuration>
2.4、开始测试
1 package com.shore.test;
2
3 import org.hibernate.cfg.Configuration;
4 import org.hibernate.tool.hbm2ddl.SchemaExport;
5 import org.junit.Test;
6
7 /**
8 * @author DSHORE/2019-9-22
9 *
10 */
11 public class XMLTest {
12 @Test
13 public void test() {//简单测试，只创建表，不插入数据
14 //xml版，这里用的是Configuration()方法。
15 new SchemaExport(new Configuration().configure()).create(
16 false, true);
17 }
18 }
测试结果图：
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原创作者：DSHORE 作者主页：http://www.cnblogs.com/dshore123/ 原文出自：https://www.cnblogs.com/dshore123/p/11568536.html 欢迎转载，转载务必说明出处。（如果本文对您有帮助，可以点击一下右下角的 推荐，或评论，谢谢！） |
原文地址：https://www.cnblogs.com/dshore123/p/11568536.html
时间： 2024-10-23 05:43:50