Hibernate（二）

注解高级

1.基础映射

（JPA）主键生成策略
@GeneratorValue(strategy=GenerationType.xxx)
GenerationType.IDENTITY: 适宜MySQL、SqlServer有自增长列的数据库。
GenerationType.SEQUENCE：适宜Oracle这种没有自增长有sequence的数据库。
GenerationType.AUTO：让Hibernate根据数据库方言自动选择主键生成策略。
GenerationType.TABLE: 适宜所有的数据库,因为它会单独生成一张表来维护主键生成。

 1 package com.rong.entity;
 2 
 3 import java.math.BigDecimal;
 4 import java.util.Date;
 5 
 6 import javax.persistence.Column;
 7 import javax.persistence.Entity;
 8 import javax.persistence.GeneratedValue;
 9 import javax.persistence.GenerationType;
10 import javax.persistence.Id;
11 import javax.persistence.Lob;
12 import javax.persistence.Table;
13 import javax.persistence.Temporal;
14 import javax.persistence.TemporalType;
15 import javax.persistence.Transient;
16 @Entity(name="HibernateUser")//说明此类是一个实体类，对应数据库中的一个表(name指定表名)
17 @Table(name="MyUser"//name执行表名
18         ,catalog="hibernate"//指定数据库
19         //,indexes={@Index(columnList="name",name="uk_name",unique=true)}//用于指定表的索引列
20         //,schema="hibernate"//指定数据库 ，两者择一就可以了。
21         //,uniqueConstraints={@UniqueConstraint(columnNames={"name","salary"})}//唯一约束
22         )
23 //@Index是一个索引 columnList：指定列名  unique：是否唯一   name：指定索引的名字 
24 public class User {
25     @Id //唯一标志符
26     @GeneratedValue(strategy=GenerationType.AUTO)//主键生成策略
27     @Column(name="hid")
28     private int id;
29     @Column(name="hname"//指定列名
30             ,unique=true//唯一约束
31             ,length=37  //指定长度
32             ,nullable=false //非空约束
33             ,columnDefinition="varchar(50) NOT NULL")//列定义 包括数据类型和约束
34     private String name;
35     @Column(name="hsalary"
36             ,precision=5//有效的总位数。(BigDecimal)会四舍五入
37             ,scale=2 //指定小数位数
38             ,insertable=false//false是不允许插入  true是允许插入
39             ,updatable=true//false是不允许更新  true是允许更新
40             )
41     private BigDecimal salary;
42     @Lob //大文本。映射大的二进制数或者文本
43     /*注意：要修改一下数据库my.ini
44       max_allowed_packet = 1M
45           这个数太小了，存储图片不够。*/
46     private String description;
47     @Temporal(TemporalType.TIMESTAMP)//时间日期处理。修饰日期类型Date
48     /*TemporalType.DATE : yyyy-MM-dd
49       TemporalType.TIME : HH:mm:ss
50       TemporalType.TIMESTAMP : yyyy-MM-dd HH:mm:ss*/
51     private Date birthday;
52     @Transient//不生成数据库字段。指定不是持久化属性
53     //transient关键字修饰不需要序列化的属性,同时用它也能指定不是持久化的属性。
54     private int flag;
55     public int getId() {
56         return id;
57     }
58     public void setId(int id) {
59         this.id = id;
60     }
61     public String getName() {
62         return name;
63     }
64     public void setName(String name) {
65         this.name = name;
66     }
67     public BigDecimal getSalary() {
68         return salary;
69     }
70     public void setSalary(BigDecimal salary) {
71         this.salary = salary;
72     }
73     public String getDescription() {
74         return description;
75     }
76     public void setDescription(String description) {
77         this.description = description;
78     }
79     public Date getBirthday() {
80         return birthday;
81     }
82     public void setBirthday(Date birthday) {
83         this.birthday = birthday;
84     }
85     public int getFlag() {
86         return flag;
87     }
88     public void setFlag(int flag) {
89         this.flag = flag;
90     }
91 }

2.主键映射

A.一个主键

B.多个主键（联合主键）

 1 package com.rong.entity;
 2 
 3 import java.io.Serializable;
 4 import java.math.BigDecimal;
 5 
 6 import javax.persistence.Entity;
 7 import javax.persistence.Id;
 8 import javax.persistence.Table;
 9 @Entity
10 @Table(name="MyUser")
11 public class User implements Serializable{
12     private static final long serialVersionUID = 6513230274782818419L;
13     //多主键的时候 不能使用@GeneratedValue,还需要实现Serializable接口
14     @Id 
15     private int id;
16     @Id
17     private String name;
18     private BigDecimal salary;
19     public int getId() {
20         return id;
21     }
22     public void setId(int id) {
23         this.id = id;
24     }
25     public String getName() {
26         return name;
27     }
28     public void setName(String name) {
29         this.name = name;
30     }
31     public BigDecimal getSalary() {
32         return salary;
33     }
34     public void setSalary(BigDecimal salary) {
35         this.salary = salary;
36     }
37 }

3.联合主键

A.分开写法

　　如上所示。

B.组合写法

把需要作为主键的字段组合成一个类，并且该类必须实现Serializable接口。

 1 package com.rong.entity;
 2 
 3 import java.io.Serializable;
 4 
 5 import javax.persistence.Column;
 6 
 7 public class Name implements Serializable{
 8     private static final long serialVersionUID = -980163939442679798L;
 9     @Column(name="first_name")//可在此处修改列名
10     private String firstName;
11     @Column(name="last_name")//可在此处修改列名
12     private String lastName;
13     public String getFirstName() {
14         return firstName;
15     }
16     public void setFirstName(String firstName) {
17         this.firstName = firstName;
18     }
19     public String getLastName() {
20         return lastName;
21     }
22     public void setLastName(String lastName) {
23         this.lastName = lastName;
24     }
25 }

在hibernate.cfg.xml中配置实体类

 

 1 package com.rong.entity;
 2 
 3 import javax.persistence.AttributeOverride;
 4 import javax.persistence.AttributeOverrides;
 5 import javax.persistence.Column;
 6 import javax.persistence.EmbeddedId;
 7 import javax.persistence.Entity;
 8 @Entity
 9 public class Person {
10     @EmbeddedId
11     //也可在此处修改列名（列名取决于本类的修改）
12     @AttributeOverrides(value={@AttributeOverride(column=@Column(name="f_n"), name = "firstName"),
13                                 @AttributeOverride(column = @Column(name="l_n"), name = "lastName")})
14     private Name name;
15 
16     public Name getName() {
17         return name;
18     }
19 
20     public void setName(Name name) {
21         this.name = name;
22     }
23 }

4.集合映射

A.List集合（List集合生成表的主键列：【外键列 + 排序列】）

list里面放的是系统自带类型：

 1 package com.rong.entity;
 2 
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 import javax.persistence.CollectionTable;
 7 import javax.persistence.ElementCollection;
 8 import javax.persistence.Entity;
 9 import javax.persistence.FetchType;
10 import javax.persistence.GeneratedValue;
11 import javax.persistence.GenerationType;
12 import javax.persistence.Id;
13 import javax.persistence.OrderColumn;
14 import javax.persistence.Table;
15 @Entity
16 @Table(name="MyUser")
17 public class User{
18     @Id
19     @GeneratedValue(strategy=GenerationType.AUTO)
20     private int id;
21     private String name;
22     @ElementCollection(targetClass=String.class// 指定集合中元素的类型
23                         ,fetch=FetchType.LAZY // 加载策略，懒加载
24                         )
25     @CollectionTable(name="MyAddress") // 指定集合生成的表
26     @OrderColumn(name="address") // 指定排序列
27     private List<String> addr=new ArrayList<String>();
28     @Override
29     public String toString() {
30         return "User [id=" + id + ", name=" + name + ", addr=" + addr + "]";
31     }
32     public List<String> getAddr() {
33         return addr;
34     }
35     public void setAddr(List<String> addr) {
36         this.addr = addr;
37     }
38     public int getId() {
39         return id;
40     }
41     public void setId(int id) {
42         this.id = id;
43     }
44     public String getName() {
45         return name;
46     }
47     public void setName(String name) {
48         this.name = name;
49     }
50 }

 

list里面放的是自定义类型：

 1 package com.rong.entity;
 2 
 3 import javax.persistence.Embeddable;
 4 
 5 @Embeddable
 6 public class Address {
 7     public Address(String addr) {
 8         super();
 9         this.addr = addr;
10     }
11 
12     public Address() {
13         super();
14     }
15 
16     private String addr;
17     
18 
19     public String getAddr() {
20         return addr;
21     }
22 
23     public void setAddr(String addr) {
24         this.addr = addr;
25     }
26 }
 1 package com.rong.entity;
 2 
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 import javax.persistence.CollectionTable;
 7 import javax.persistence.ElementCollection;
 8 import javax.persistence.Entity;
 9 import javax.persistence.FetchType;
10 import javax.persistence.GeneratedValue;
11 import javax.persistence.GenerationType;
12 import javax.persistence.Id;
13 import javax.persistence.OrderColumn;
14 import javax.persistence.Table;
15 @Entity
16 @Table(name="MyUser")
17 public class User{
18     @Id
19     @GeneratedValue(strategy=GenerationType.AUTO)
20     private int id;
21     private String name;
22     @ElementCollection(targetClass=Address.class// 指定集合中元素的类型
23                         ,fetch=FetchType.LAZY // 加载策略，懒加载
24                         )
25     @CollectionTable(name="MyAddress") // 指定集合生成的表
26     @OrderColumn(name="address_sort") // 指定排序列
27     private List<Address> addr=new ArrayList<Address>();
28     @Override
29     public String toString() {
30         return "User [id=" + id + ", name=" + name + ", addr=" + addr + "]";
31     }
32     public List<Address> getAddr() {
33         return addr;
34     }
35     public void setAddr(List<Address> addr) {
36         this.addr = addr;
37     }
38     public int getId() {
39         return id;
40     }
41     public void setId(int id) {
42         this.id = id;
43     }
44     public String getName() {
45         return name;
46     }
47     public void setName(String name) {
48         this.name = name;
49     }
50 }

 B.Set集合（Set集合生成表的主键列：【外键列 + Set集合的元素列 .. 】）

set里面放的是系统自带类型：

Set集合生成表默认是没有主键列的。如果想要生成主键列，需要为Set集合添加非空约束！

 1 package com.rong.entity;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 import javax.persistence.CollectionTable;
 7 import javax.persistence.Column;
 8 import javax.persistence.ElementCollection;
 9 import javax.persistence.Entity;
10 import javax.persistence.FetchType;
11 import javax.persistence.GeneratedValue;
12 import javax.persistence.GenerationType;
13 import javax.persistence.Id;
14 import javax.persistence.Table;
15 @Entity
16 @Table(name="MyUser")
17 public class User{
18     @Id
19     @GeneratedValue(strategy=GenerationType.AUTO)
20     private int id;
21     private String name;
22     @ElementCollection(targetClass=String.class// 指定集合中元素的类型
23                         ,fetch=FetchType.LAZY // 加载策略，懒加载
24                         )
25     @CollectionTable(name="MyAddress") // 指定集合生成的表
26     @Column(nullable=false)// 添加非空约束
27     private Set<String> addr=new HashSet<String>();
28     @Override
29     public String toString() {
30         return "User [id=" + id + ", name=" + name + ", addr=" + addr + "]";
31     }
32     
33     public Set<String> getAddr() {
34         return addr;
35     }
36 
37     public void setAddr(Set<String> addr) {
38         this.addr = addr;
39     }
40 
41     public int getId() {
42         return id;
43     }
44     public void setId(int id) {
45         this.id = id;
46     }
47     public String getName() {
48         return name;
49     }
50     public void setName(String name) {
51         this.name = name;
52     }
53 }
 1 package com.rong.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.hibernate.boot.registry.StandardServiceRegistryBuilder;
 9 import org.hibernate.cfg.Configuration;
10 import org.hibernate.service.ServiceRegistry;
11 import org.junit.Test;
12 
13 import com.rong.entity.User;
14 
15 public class HibernateTest {
16     @Test
17     public void test1(){
18         Configuration configuration=new Configuration().configure();
19         ServiceRegistry serviceRegistry=new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
20         SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);
21         Session session = sessionFactory.openSession();
22         Transaction transaction = session.beginTransaction();
23         
24         User user=new User();
25         user.setName("OK");
26         Set<String> addr = user.getAddr();
27         addr.add("中国");
28         addr.add("法国");
29         addr.add("英国");
30         addr.add("美国");
31 
32         session.save(user);
33         //查找user
34         User findUser = (User) session.get(User.class, 1);
35         System.out.println(findUser);
36         transaction.commit();
37         session.close();
38         sessionFactory.close();
39     }
40 }

set里面放的是自定义类型：

 1 package com.rong.entity;
 2 
 3 import javax.persistence.Embeddable;
 4 
 5 @Embeddable
 6 public class Address {
 7     public Address(String addr) {
 8         super();
 9         this.addr = addr;
10     }
11 
12     public Address() {
13         super();
14     }
15 
16     private String addr;
17     
18 
19     public String getAddr() {
20         return addr;
21     }
22 
23     public void setAddr(String addr) {
24         this.addr = addr;
25     }
26 
27     @Override
28     public String toString() {
29         return "Address [addr=" + addr + "]";
30     }
31 }
 1 package com.rong.entity;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 import javax.persistence.CollectionTable;
 7 import javax.persistence.ElementCollection;
 8 import javax.persistence.Entity;
 9 import javax.persistence.FetchType;
10 import javax.persistence.GeneratedValue;
11 import javax.persistence.GenerationType;
12 import javax.persistence.Id;
13 import javax.persistence.Table;
14 @Entity
15 @Table(name="MyUser")
16 public class User{
17     @Id
18     @GeneratedValue(strategy=GenerationType.AUTO)
19     private int id;
20     private String name;
21     @ElementCollection(targetClass=Address.class// 指定集合中元素的类型
22                         ,fetch=FetchType.LAZY // 加载策略，懒加载
23                         )
24     @CollectionTable(name="MyAddress") // 指定集合生成的表
25     private Set<Address> addr=new HashSet<Address>();
26     @Override
27     public String toString() {
28         return "User [id=" + id + ", name=" + name + ", addr=" + addr + "]";
29     }
30     
31     public Set<Address> getAddr() {
32         return addr;
33     }
34 
35     public void setAddr(Set<Address> addr) {
36         this.addr = addr;
37     }
38 
39     public int getId() {
40         return id;
41     }
42     public void setId(int id) {
43         this.id = id;
44     }
45     public String getName() {
46         return name;
47     }
48     public void setName(String name) {
49         this.name = name;
50     }
51 }
 1 package com.rong.test;
 2 
 3 import java.util.List;
 4 import java.util.Set;
 5 
 6 import org.hibernate.Session;
 7 import org.hibernate.SessionFactory;
 8 import org.hibernate.Transaction;
 9 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
10 import org.hibernate.cfg.Configuration;
11 import org.hibernate.service.ServiceRegistry;
12 import org.junit.Test;
13 
14 import com.rong.entity.Address;
15 import com.rong.entity.User;
16 
17 public class HibernateTest {
18     @Test
19     public void test1(){
20         Configuration configuration=new Configuration().configure();
21         ServiceRegistry serviceRegistry=new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
22         SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);
23         Session session = sessionFactory.openSession();
24         Transaction transaction = session.beginTransaction();
25         
26         User user=new User();
27         user.setName("OK");
28         Set<Address> addr = user.getAddr();
29         addr.add(new Address("中国"));
30         addr.add(new Address("美国"));
31         addr.add(new Address("英国"));
32         addr.add(new Address("德国"));
33 
34         session.save(user);
35         //查找user
36         User findUser = (User) session.get(User.class, 1);
37         System.out.println(findUser);
38         transaction.commit();
39         session.close();
40         sessionFactory.close();
41     }
42 }

 C.Map集合（Map集合生成表的主键列：【外键列 + Map的Key】）

value值是系统自带的类型

 1 package com.rong.entity;
 2 
 3 import java.util.HashMap;
 4 import java.util.Map;
 5 
 6 import javax.persistence.CollectionTable;
 7 import javax.persistence.ElementCollection;
 8 import javax.persistence.Entity;
 9 import javax.persistence.FetchType;
10 import javax.persistence.GeneratedValue;
11 import javax.persistence.GenerationType;
12 import javax.persistence.Id;
13 import javax.persistence.MapKeyColumn;
14 import javax.persistence.Table;
15 @Entity
16 @Table(name="MyUser")
17 public class User{
18     @Id
19     @GeneratedValue(strategy=GenerationType.AUTO)
20     private int id;
21     private String name;
22     @ElementCollection(targetClass=String.class// 指定集合中元素value值的类型
23                         ,fetch=FetchType.LAZY // 加载策略，懒加载
24                         )
25     @CollectionTable(name="MyMap") // 指定集合生成的表
26     @MapKeyColumn(name="map_key")//指定map的key生成的列
27     private Map<String,String> map=new HashMap<String,String>();//成员变量起什么名字，列名就是什么
28     
29     public int getId() {
30         return id;
31     }
32     public void setId(int id) {
33         this.id = id;
34     }
35     public String getName() {
36         return name;
37     }
38     public void setName(String name) {
39         this.name = name;
40     }
41     public Map<String, String> getMap() {
42         return map;
43     }
44     public void setMap(Map<String, String> map) {
45         this.map = map;
46     }
47     @Override
48     public String toString() {
49         return "User [id=" + id + ", name=" + name + ", map=" + map + "]";
50     }
51 }
 1 package com.rong.test;
 2 
 3 import java.util.Map;
 4 import java.util.Set;
 5 
 6 import org.hibernate.Session;
 7 import org.hibernate.SessionFactory;
 8 import org.hibernate.Transaction;
 9 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
10 import org.hibernate.cfg.Configuration;
11 import org.hibernate.service.ServiceRegistry;
12 import org.junit.Test;
13 
14 import com.rong.entity.User;
15 
16 public class HibernateTest {
17     @Test
18     public void test1(){
19         Configuration configuration=new Configuration().configure();
20         ServiceRegistry serviceRegistry=new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
21         SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);
22         Session session = sessionFactory.openSession();
23         Transaction transaction = session.beginTransaction();
24         
25         User user=new User();
26         user.setName("kobe");
27         Map<String, String> map = user.getMap();
28         map.put("height", "198");
29         map.put("weight", "123");
30         map.put("hobby", "basketball");
31         session.save(user);
32         //查找user
33         User findUser = (User) session.get(User.class, 1);
34         System.out.println(findUser);
35         transaction.commit();
36         session.close();
37         sessionFactory.close();
38     }
39 }

value值是自定义的类型

注意：类名（表名）、成员变量名（列名）不能使用数据库的关键字！！！

 1 package com.rong.entity;
 2 
 3 import java.util.HashMap;
 4 import java.util.Map;
 5 
 6 import javax.persistence.CollectionTable;
 7 import javax.persistence.ElementCollection;
 8 import javax.persistence.Entity;
 9 import javax.persistence.FetchType;
10 import javax.persistence.GeneratedValue;
11 import javax.persistence.GenerationType;
12 import javax.persistence.Id;
13 import javax.persistence.MapKeyColumn;
14 import javax.persistence.Table;
15 @Entity
16 @Table(name="MyUser")
17 public class User{
18     @Id
19     @GeneratedValue(strategy=GenerationType.AUTO)
20     private int id;
21     private String name;
22     @ElementCollection(targetClass=Infos.class// 指定集合中元素value值的类型
23                         ,fetch=FetchType.LAZY // 加载策略，懒加载
24                         )
25     @CollectionTable(name="MyMap") // 指定集合生成的表
26     @MapKeyColumn(name="map_key")//指定map的key生成的列
27     private Map<String,Infos> infoMap=new HashMap<String,Infos>();//成员变量起什么名字，列名就是什么
28     
29     public int getId() {
30         return id;
31     }
32     public void setId(int id) {
33         this.id = id;
34     }
35     public String getName() {
36         return name;
37     }
38     public void setName(String name) {
39         this.name = name;
40     }
41     public Map<String, Infos> getInfoMap() {
42         return infoMap;
43     }
44     public void setInfoMap(Map<String, Infos> infoMap) {
45         this.infoMap = infoMap;
46     }
47     @Override
48     public String toString() {
49         return "User [id=" + id + ", name=" + name + ", infoMap=" + infoMap + "]";
50     }
51 }
 1 package com.rong.entity;
 2 
 3 import javax.persistence.Embeddable;
 4 
 5 @Embeddable
 6 public class Infos {
 7     public Infos(String describe) {
 8         super();
 9         this.intro = describe;
10     }
11 
12     public Infos() {
13         super();
14     }
15 
16     private String intro;
17 
18     public String getDescribe() {
19         return intro;
20     }
21 
22     public void setDescribe(String describe) {
23         this.intro = describe;
24     }
25 
26     @Override
27     public String toString() {
28         return "Information [describe=" + intro + "]";
29     }
30 }

User [id=1, name=huge, infoMap={weight=Information [describe=65], height=Information [describe=182], hobby=Information [describe=movie]}]

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原文地址：https://www.cnblogs.com/57rongjielong/p/8214645.html