hibernate关系映射学习小结
一、一对多映射(one-to-many)
hibernateXML配置文件：
1 <!DOCTYPE hibernate-configuration PUBLIC 2 "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 3 "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 4 5 <hibernate-configuration> 6 <session-factory> 7 <!-- 配置连接目标数据库的属性 --> 8 <property name="connection.driver_class"> 9 oracle.jdbc.OracleDriver 10 </property> 11 <property name="connection.url"> 12 jdbc:oracle:thin:@127.0.0.1:1521:xe 13 </property> 14 <property name="connection.username">etc1616</property> 15 <property name="connection.password">123</property> 16 17 <!-- 配置方言 --> 18 <property name="dialect"> 19 org.hibernate.dialect.Oracle10gDialect 20 </property> 21 22 <!-- 是否要显示Hibernate生成的sql语句 --> 23 <property name="show_sql">true</property> 24 <!-- 是否要格式化显示出的SQL --> 25 <property name="format_sql">true</property> 26 27 <!-- 打开自动创建DDL --> 28 <property name="hbm2ddl.auto">update</property> 29 30 <!-- 配置C3P0连接池组件 31 <property name="c3p0.max_size">5</property> 32 <property name="c3p0.min_size">2</property> 33 <property name="c3p0.timeout">5000</property> 34 <property name="c3p0.idle_test_period">3000</property> 35 <property name="c3p0.acquire_increment">1</property> 36 <property name="c3p0.max_statements">150</property> 37 --> 38 <!-- 开启二级缓存 39 <property name="cache.use_second_level_cache">true</property>--> 40 <!-- 指定二级缓存供应商 41 <property name="cache.region.factory_class"> 42 org.hibernate.cache.ehcache.EhCacheRegionFactory 43 </property> 44 --> 45 46 47 <!-- 开启查询缓存 48 <property name="cache.use_query_cache">true</property>--> 49 <!-- 读取映射文件 --> 50 <!--<mapping resource="com/hbm/entity/Account.hbm.xml" />--> 51 <!-- <mapping resource="com/hbm/entity/Student.hbm.xml" /> 52 <mapping resource="com/hbm/entity/Class.hbm.xml" /> --> 53 <!-- 读取实体 --> 54 <!-- <mapping class="com.hbm.entity.Book" /> 55 <mapping class="com.hbm.entity.BookInfo" /> 56 <mapping class="com.hbm.entity.Customer" /> 57 <mapping class="com.hbm.entity.Order" /> 58 <mapping class="com.hbm.entity.Role" /> 59 <mapping class="com.hbm.entity.User" />--> 60 <mapping class="com.hbm.entity.Category" /> 61 <mapping class="com.hbm.entity.Product" /> 62 <!-- <mapping class="com.hbm.entity.User" /> 63 <mapping class="com.hbm.entity.Role" /> --> 64 65 </session-factory> 66 </hibernate-configuration>
Product类：
1 package com.hbm.entity;
2
3 import javax.persistence.Column;
4 import javax.persistence.Entity;
5 import javax.persistence.FetchType;
6 import javax.persistence.GeneratedValue;
7 import javax.persistence.Id;
8 import javax.persistence.JoinColumn;
9 import javax.persistence.ManyToOne;
10 import javax.persistence.Table;
11 import org.hibernate.annotations.GenericGenerator;
12
13
14 @Entity
15 @Table(name = "product")
16 public class Product {
17
18 private Integer id;
19 private Category category;
20 private String name;
21 private String price;
22 private String descripton;
23
24
25 public Product() {
26 // TODO Auto-generated constructor stub
27 }
28
29 public Product(Category category, String name, String price,String descripton) {
30 this.category = category;
31 this.name = name;
32 this.price = price;
33 this.descripton = descripton;
34
35 }
36
37 @Id
38 @GenericGenerator(name = "generator", strategy = "increment")
39 @GeneratedValue(generator = "generator")
40 @Column(name = "id", unique = true, nullable = false)
41 public Integer getId() {
42 return this.id;
43 }
44
45 public void setId(Integer id) {
46 this.id = id;
47
48 }
49
50 //延迟加载：多对一方式
51 //关联信息：外键name = "category_id"
52 @ManyToOne(fetch = FetchType.LAZY)
53 @JoinColumn(name = "category_id")
54 public Category getCategory() {
55 return this.category;
56 }
57
58 public void setCategory(Category category) {
59 this.category = category;
60 }
61
62 @Column(name = "name", length = 500)
63 public String getName() {
64 return this.name;
65 }
66
67 public void setName(String name) {
68 this.name = name;
69 }
70
71 @Column(name = "price", length = 10)
72 public String getPrice() {
73 return this.price;
74 }
75
76 public void setPrice(String price) {
77 this.price = price;
78 }
79
80 @Column(name = "descripton", length = 500)
81 public String getDescripton() {
82 return this.descripton;
83 }
84
85 public void setDescripton(String descripton) {
86 this.descripton = descripton;
87
88 }
89
90 @Override
91 public String toString() {
92 return "Product [id=" + id + ", category=" + category + ", name="
93 + name + ", price=" + price + ", descripton=" + descripton
94 + "]";
95 }
96
97
98 }
Category类：
1 package com.hbm.entity;
2
3 import java.util.HashSet;
4 import java.util.Set;
5 import javax.persistence.CascadeType;
6 import javax.persistence.Column;
7 import javax.persistence.Entity;
8 import javax.persistence.FetchType;
9 import javax.persistence.GeneratedValue;
10 import javax.persistence.Id;
11 import javax.persistence.OneToMany;
12 import javax.persistence.Table;
13 import org.hibernate.annotations.GenericGenerator;
14
15
16 @Entity
17 @Table(name = "category")
18 public class Category{
19
20 private Integer id;
21 private String name;
22 private String description;
23 private Set<Product> products = new HashSet<Product>();
24
25 public Category() {
26
27 }
28
29 public Category(String name, String description, Set<Product> products) {
30 this.name = name;
31 this.description = description;
32 this.products = products;
33
34 }
35
36 //主键 ：@Id 主键生成方式：strategy = "increment"
37 //映射表中id这个字段，不能为空，并且是唯一的
38 @Id
39 @GenericGenerator(name = "generator", strategy = "increment")
40 @GeneratedValue(generator = "generator")
41 @Column(name = "id", unique = true, nullable = false)
42 public Integer getId() {
43 return this.id;
44 }
45
46 public void setId(Integer id) {
47 this.id = id;
48 }
49
50 //映射表中name这个字段 ，长度是500
51 @Column(name = "name", length = 500)
52 public String getName() {
53 return this.name;
54 }
55
56 public void setName(String name) {
57 this.name = name;
58 }
59
60 //映射表中description这个字段 ，长度是500
61 @Column(name = "description", length = 500)
62 public String getDescription() {
63 return this.description;
64 }
65
66 public void setDescription(String description) {
67 this.description = description;
68 }
69
70 //级联操作：cascade = CascadeType.ALL
71 //延迟加载：fetch = FetchType.LAZY
72 //映射：mappedBy = "category"
73 //一对多方式
74 @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "category")
75 public Set<Product> getProducts() {
76 return this.products;
77 }
78
79 public void setProducts(Set<Product> products) {
80 this.products = products;
81 }
82
83 @Override
84 public String toString() {
85 return "Category [id=" + id + ", name=" + name + ", description="
86 + description + "]";
87 }
88
89
90 }
测试类：
1 package com.hbm.test;
2
3 import java.util.Set;
4
5 import org.hibernate.Session;
6 import org.hibernate.SessionFactory;
7 import org.hibernate.Transaction;
8 import org.junit.Test;
9 import com.hbm.Util.HibernateUtil;
10 import com.hbm.entity.Category;
11 import com.hbm.entity.Product;
12
13 public class Category_Test {
14
15
16 SessionFactory sf=HibernateUtil.getSessionFactory();
17 Session session=sf.openSession();
18 Transaction ts=session.beginTransaction();
19
20 @Test
21 public void test1(){
22
23 Product p=new Product();
24 p.setName("大语文");
25 p.setPrice("123");
26 p.setDescripton("编程语言");
27
28
29 Category c=new Category();
30 c.setId(1);
31 c.setName("李四");
32 c.setDescription("ok");
33
34 //建立双向关联
35
36 c.getProducts().add(p);
37 p.setCategory(c);
38
39 session.save(c);
40
41 ts.commit();
42 session.close();
43
44
45 }
46
47
48 @Test
49 public void test2(){
50
51 Category c=(Category)session.get(Category.class, 1);
52 Set<Product> p=c.getProducts();
53 for(Product product:p){
54 System.out.println(product);
55 }
56 System.out.println(c);
57 ts.commit();
58
59 }
60
61
62 }
三、多对多映射(many-to-many)
hibernateXML配置文件：
1 <!DOCTYPE hibernate-configuration PUBLIC
2 "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
3 "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
4
5 <hibernate-configuration>
6 <session-factory>
7 <!-- 配置连接目标数据库的属性 -->
8 <property name="connection.driver_class">
9 oracle.jdbc.OracleDriver
10 </property>
11 <property name="connection.url">
12 jdbc:oracle:thin:@127.0.0.1:1521:xe
13 </property>
14 <property name="connection.username">etc1616</property>
15 <property name="connection.password">123</property>
16
17 <!-- 配置方言 -->
18 <property name="dialect">
19 org.hibernate.dialect.Oracle10gDialect
20 </property>
21
22 <!-- 是否要显示Hibernate生成的sql语句 -->
23 <property name="show_sql">true</property>
24 <!-- 是否要格式化显示出的SQL -->
25 <property name="format_sql">true</property>
26
27 <!-- 打开自动创建DDL -->
28 <property name="hbm2ddl.auto">update</property>
29
30 <!-- 配置C3P0连接池组件
31 <property name="c3p0.max_size">5</property>
32 <property name="c3p0.min_size">2</property>
33 <property name="c3p0.timeout">5000</property>
34 <property name="c3p0.idle_test_period">3000</property>
35 <property name="c3p0.acquire_increment">1</property>
36 <property name="c3p0.max_statements">150</property>
37 -->
38 <!-- 开启二级缓存
39 <property name="cache.use_second_level_cache">true</property>-->
40 <!-- 指定二级缓存供应商
41 <property name="cache.region.factory_class">
42 org.hibernate.cache.ehcache.EhCacheRegionFactory
43 </property>
44 -->
45
46
47 <!-- 开启查询缓存
48 <property name="cache.use_query_cache">true</property>-->
49 <!-- 读取映射文件 -->
50 <!--<mapping resource="com/hbm/entity/Account.hbm.xml" />-->
51 <!-- <mapping resource="com/hbm/entity/Student.hbm.xml" />
52 <mapping resource="com/hbm/entity/Class.hbm.xml" /> -->
53 <!-- 读取实体 -->
54 <!-- <mapping class="com.hbm.entity.Book" />
55 <mapping class="com.hbm.entity.BookInfo" />
56 <mapping class="com.hbm.entity.Customer" />
57 <mapping class="com.hbm.entity.Order" />
58 <mapping class="com.hbm.entity.Role" />
59 <mapping class="com.hbm.entity.User" />-->
60 <mapping class="com.hbm.entity.User" />
61 <mapping class="com.hbm.entity.Role" />
62
63 </session-factory>
64 </hibernate-configuration>
User类：
1 package com.hbm.entity;
2
3 import java.util.ArrayList;
4 import java.util.List;
5 import javax.persistence.Entity;
6 import javax.persistence.GeneratedValue;
7 import javax.persistence.Id;
8 import javax.persistence.JoinColumn;
9 import javax.persistence.JoinTable;
10 import javax.persistence.ManyToMany;
11
12 @Entity(name="hbl_user")
13 public class User {
14
15 private int user_id;
16 private String user_name;
17 private List<Role> rs_id=new ArrayList<Role>();
18
19
20 public User() {
21 // TODO Auto-generated constructor stub
22 }
23
24
25 public User(int user_id, String user_name, List<Role> rs_id) {
26 super();
27 this.user_id = user_id;
28 this.user_name = user_name;
29 this.rs_id = rs_id;
30 }
31
32 @Id
33 @GeneratedValue
34 public int getUser_id() {
35 return user_id;
36 }
37
38
39 public void setUser_id(int user_id) {
40 this.user_id = user_id;
41 }
42
43 @JoinColumn
44 public String getUser_name() {
45 return user_name;
46 }
47
48
49 public void setUser_name(String user_name) {
50 this.user_name = user_name;
51 }
52
53 @ManyToMany()
54 @JoinTable(
55 //中间表的自定义列名,与之相对应的关联表的主键名
56 joinColumns=@JoinColumn(name="user_id",referencedColumnName="user_id"),
57 //中间表的自定义列名,与之相对应的关联表的主键名
58 inverseJoinColumns=@JoinColumn(name="role_id",referencedColumnName="role_id")
59 )
60 public List<Role> getRs_id() {
61 return rs_id;
62 }
63
64
65 public void setRs_id(List<Role> rs_id) {
66 this.rs_id = rs_id;
67 }
68
69
70 }
Role类：
1 package com.hbm.entity;
2
3 import java.util.ArrayList;
4 import java.util.List;
5
6 import javax.persistence.Column;
7 import javax.persistence.Entity;
8 import javax.persistence.GeneratedValue;
9 import javax.persistence.Id;
10 import javax.persistence.ManyToMany;
11
12
13 @Entity(name="hbl_role")
14 public class Role {
15
16 private int role_id;
17 private String role_name;
18 private double price;
19 private List<User> us_id=new ArrayList<User>();
20
21 public Role() {
22 // TODO Auto-generated constructor stub
23 }
24
25 public Role(int role_id, String role_name, double price, List<User> us_id) {
26 super();
27 this.role_id = role_id;
28 this.role_name = role_name;
29 this.price = price;
30 this.us_id = us_id;
31 }
32
33 @Id
34 @GeneratedValue
35 public int getRole_id() {
36 return role_id;
37 }
38
39 public void setRole_id(int role_id) {
40 this.role_id = role_id;
41 }
42
43 @Column
44 public String getRole_name() {
45 return role_name;
46 }
47
48 public void setRole_name(String role_name) {
49 this.role_name = role_name;
50 }
51
52 @Column
53 public double getPrice() {
54 return price;
55 }
56
57 public void setPrice(double price) {
58 this.price = price;
59 }
60
61 @ManyToMany
62 public List<User> getUs_id() {
63 return us_id;
64 }
65
66 public void setUs_id(List<User> us_id) {
67 this.us_id = us_id;
68 }
69
70
71
72
73
74 }
测试类：
1 package com.hbm.test;
2
3 import java.util.Iterator;
4 import org.hibernate.Session;
5 import org.hibernate.SessionFactory;
6 import org.hibernate.Transaction;
7 import org.junit.Test;
8 import com.hbm.Util.HibernateUtil;
9 import com.hbm.entity.Role;
10 import com.hbm.entity.User;
11
12 public class User_Test {
13
14 SessionFactory sf=HibernateUtil.getSessionFactory();
15 Session session=sf.openSession();
16 Transaction ts=session.beginTransaction();
17
18
19 //插入数据
20 @Test
21 public void test1(){
22
23 User u1=new User();
24 u1.setUser_name("乔峰");
25
26 User u2=new User();
27 u2.setUser_name("段誉");
28
29
30 Role c1=new Role();
31 c1.setRole_name("丐帮帮主");
32 c1.setPrice(100.0);
33
34 Role c2=new Role();
35 c2.setRole_name("大理王子");
36 c2.setPrice(200.0);
37
38 Role c3=new Role();
39 c3.setRole_name("武林高手");
40 c3.setPrice(300.0);
41
42 u1.getRs_id().add(c1);
43 u1.getRs_id().add(c3);
44
45 u2.getRs_id().add(c1);
46 u2.getRs_id().add(c2);
47 u2.getRs_id().add(c3);
48
49 c1.getUs_id().add(u1);
50 c3.getUs_id().add(u2);
51
52
53 session.save(u1);
54 session.save(u2);
55
56 session.save(c1);
57 session.save(c2);
58 session.save(c3);
59
60 ts.commit();
61 session.close();
62
63
64 }
65
66 //查询
67 @Test
68 public void test2(){
69
70 User us =(User) session.get(User.class, 2);
71 System.out.println("我的名字是："+us.getUser_name());
72 System.out.println("我的角色是：");
73 Iterator<Role> it = us.getRs_id().iterator();
74 while(it.hasNext()){
75 System.out.println(it.next().getRole_name());
76 }
77
78 ts.commit();
79 session.close();
80
81 }
82 //删除
83 @Test
84 public void test3(){
85
86 User us =(User) session.get(User.class, 1);
87 Role rs =(Role) session.get(Role.class, 3);
88
89 us.getRs_id().remove(rs);
90 rs.getUs_id().remove(us);
91
92 ts.commit();
93 session.close();
94
95
96 }
97 //更新
98 @Test
99 public void test4(){
100
101 User us =(User) session.get(User.class, 2);
102 Role rs1 =(Role) session.get(Role.class, 3);
103 Role rs2 =(Role) session.get(Role.class, 4);
104
105
106 us.getRs_id().remove(rs1);
107 rs1.getUs_id().remove(us);
108
109
110 us.getRs_id().add(rs2);
111 rs2.getUs_id().add(us);
112
113
114 ts.commit();
115 session.close();
116
117
118 }
119
120
121 }
