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hibernate3學習筆記(十六)｜容器映射

編輯：關於JAVA

1.Set映射

DDL:

1.CREATE TABLE user (
2.    id INT(11) NOT NULL auto_increment PRIMARY KEY,
3.    name VARCHAR(100) NOT NULL default ''
4. );
5.
6.CREATE TABLE email (
7.    id INT(11) NOT NULL,
8.    address VARCHAR(100) NOT NULL
9.);

User.java

1.package com.hb3.pack_11.model;
2.
3.import java.util.Set;
4.
5.public class User {
6.
7.    private Integer id;
8.    private String name;
9.    private Set<String> emails;
10.
11.    public User() {
12.    }
13.
14.    public Integer getId() {
15.        return id;
16.    }
17.    public void setId(Integer id) {
18.        this.id = id;
19.    }
20.    public String getName() {
21.        return name;
22.    }
23.    public void setName(String name) {
24.        this.name = name;
25.    }
26.    public Set<String> getEmails() {
27.        return emails;
28.    }
29.    public void setEmails(Set<String> emails) {
30.        this.emails = emails;
31.    }
32.    public void addEmail(String email) {
33.        this.emails.add(email);
34.    }
35.    public void removeEmail(String email) {
36.        this.emails.remove(email);
37.    }
38.}

User.hbm.xml：

1.<?xml version="1.0" encoding="utf-8"?>
2.<!DOCTYPE hibernate-mapping
3.    PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
4.    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
5.
6.<hibernate-mapping>
7.
8.    <class name="com.hb3.pack_11.model.User" table="user">
9.
10.        <id name="id" column="id" type="java.lang.Integer">
11.            <generator class="native" />
12.        </id>
13.
14.        <property name="name" column="name" type="java.lang.String" />
15.
16.        <set name="emails" table="email">
17.            <key column="id" />
18.            <element type="java.lang.String" column="address" />
19.        </set>
20.    </class>
21.</hibernate-mapping>

測試代碼：

1.package com.hb3.pack_11;
2.
3.import java.io.IOException;
4.import java.sql.SQLException;
5.import java.util.HashSet;
6.
7.import org.hibernate.Session;
8.import org.hibernate.SessionFactory;
9.import org.hibernate.Transaction;
10.import org.hibernate.cfg.Configuration;
11.
12.import com.hb3.pack_11.model.User;
13.
14.public class BusinessService {
15.
16.    public static void main(String[] args) throws IOException, SQLException {
17.
18.        Configuration config = new Configuration().configure();
19.        SessionFactory sessionFactory = config.buildSessionFactory();
20.        Session session = sessionFactory.openSession();
21.
22.
23.        User user1 = new User();
24.        user1.setEmails(new HashSet<String>());
25.        user1.setName("shenbin");
26.        user1.addEmail("[email protected]");
27.        user1.addEmail("[email protected]");
28.
29.        User user2 = new User();
30.        user2.setEmails(new HashSet<String>());
31.        user2.setName("chenyan");
32.        user2.addEmail("[email protected]");
33.
34.        Transaction tx = session.beginTransaction();
35.        session.save(user1);
36.        session.save(user2);
37.        tx.commit();
38.
39.
40.        session.close();
41.        sessionFactory.close();
42.    }
43.}

Set的特點就是不能放置相同的物件在Set中。

也就是說，上述例子中，同一個User雖然可以對應多個emails，但是emails卻不能有相同的（對同一個人而言）。

2.List映射

DDL：

1.CREATE TABLE user (
2.    id INT(11) NOT NULL auto_increment PRIMARY KEY,
3.    name VARCHAR(100) NOT NULL default ''
4.);
5.
6.CREATE TABLE item (
7.    id INT(11) NOT NULL,
8.    position INT(11) NOT NULL,
9.    name VARCHAR(100) NOT NULL default ''
10.);

User.java

1.package com.hb3.pack_12.model;
2.
3.import java.util.List;
4.
5.public class User {
6.
7.    private Integer id;
8.    private String name;
9.    private List<String> items;
10.
11.    public User() {
12.    }
13.
14.    public Integer getId() {
15.        return id;
16.    }
17.    public void setId(Integer id) {
18.        this.id = id;
19.    }
20.    public String getName() {
21.        return name;
22.    }
23.    public void setName(String name) {
24.        this.name = name;
25.    }
26.    public List<String> getItems() {
27.        return items;
28.    }
29.    public void setItems(List<String> items) {
30.        this.items = items;
31.    }
32.    public void addItem(String item) {
33.        items.add(item);
34.    }
35.    public void removeItem(String item) {
36.        items.remove(item);
37.    }
38.}

User.hbm.xml：

1.<?xml version="1.0" encoding="utf-8"?>
2.<!DOCTYPE hibernate-mapping
3.    PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
4.    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
5.
6.<hibernate-mapping>
7.
8.    <class name="com.hb3.pack_12.model.User" table="user">
9.
10.        <id name="id" column="id" type="java.lang.Integer">
11.            <generator class="native"/>
12.        </id>
13.
14.        <property name="name" column="name" type="java.lang.String"/>
15.
16.        <list name="items" table="item">
17.            <key column="id"/>
18.            <index column="position"/>
19.            <element type="java.lang.String" column="name"/>
20.        </list>
21.
22.    </class>
23.</hibernate-mapping>

測試代碼：

1.package com.hb3.pack_12;
2.
3.import java.io.IOException;
4.import java.sql.SQLException;
5.import java.util.ArrayList;
6.
7.import org.hibernate.Session;
8.import org.hibernate.SessionFactory;
9.import org.hibernate.Transaction;
10.import org.hibernate.cfg.Configuration;
11.
12.import com.hb3.pack_12.model.User;
13.
14.public class BusinessService {
15.
16.    public static void main(String[] args) throws IOException, SQLException {
17.
18.        Configuration config = new Configuration().configure();
19.        SessionFactory sessionFactory = config.buildSessionFactory();
20.        Session session = sessionFactory.openSession();
21.
22.
23.        User user1 = new User();
24.        user1.setItems(new ArrayList<String>());
25.        user1.setName("shenbin");
26.        user1.addItem("DC");
27.        user1.addItem("CF Card");
28.
29.        User user2 = new User();
30.        user2.setItems(new ArrayList<String>());
31.        user2.setName("chenyan");
32.        user2.addItem("CD");
33.
34.        Transaction tx = session.beginTransaction();
35.        session.save(user1);
36.        session.save(user2);
37.        tx.commit();
38.
39.
40.        session.close();
41.        sessionFactory.close();
42.    }
43.}

List是有序的結構。他在存儲物品的時候還對物品所處的位置進行了記錄。

3.Bag映射

DDL：

1.CREATE TABLE user (
2.    id INT(11) NOT NULL auto_increment PRIMARY KEY,
3.    name VARCHAR(100) NOT NULL default ''
4.);
5.
6.CREATE TABLE item (
7.    id INT(11) NOT NULL,
8.    name VARCHAR(100) NOT NULL
9.);

User.java

1.package com.hb3.pack_13.model;
2.
3.import java.util.List;
4.
5.public class User {
6.
7.    private Integer id;
8.    private String name;
9.    private List<String> items;
10.
11.    public User() {
12.    }
13.
14.    public Integer getId() {
15.        return id;
16.    }
17.    public void setId(Integer id) {
18.        this.id = id;
19.    }
20.    public String getName() {
21.        return name;
22.    }
23.    public void setName(String name) {
24.        this.name = name;
25.    }
26.    public List<String> getItems() {
27.        return items;
28.    }
29.    public void setItems(List<String> items) {
30.        this.items = items;
31.    }
32.    public void addItem(String item) {
33.        items.add(item);
34.    }
35.    public void removeItem(String item) {
36.        items.remove(item);
37.    }
38.}

User.hbm.xml:

1.<?xml version="1.0" encoding="utf-8"?>
2.<!DOCTYPE hibernate-mapping
3.    PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
4.    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
5.
6.<hibernate-mapping>
7.
8.    <class name="com.hb3.pack_12.model.User" table="user">
9.
10.        <id name="id" column="id" type="java.lang.Integer">
11.            <generator class="native"/>
12.        </id>
13.
14.        <property name="name" column="name" type="java.lang.String"/>
15.
16.        <bag name="items" table="item">
17.            <key column="id"/>
18.            <element column="name" type="java.lang.String"/>
19.        </bag>
20.
21.    </class>
22.</hibernate-mapping>

測試代碼：

1.package com.hb3.pack_13;
2.
3.import java.io.IOException;
4.import java.sql.SQLException;
5.import java.util.ArrayList;
6.
7.import org.hibernate.Session;
8.import org.hibernate.SessionFactory;
9.import org.hibernate.Transaction;
10.import org.hibernate.cfg.Configuration;
11.
12.import com.hb3.pack_12.model.User;
13.
14.public class BusinessService {
15.
16.    public static void main(String[] args) throws IOException, SQLException {
17.
18.        Configuration config = new Configuration().configure();
19.        SessionFactory sessionFactory = config.buildSessionFactory();
20.        Session session = sessionFactory.openSession();
21.
22.
23.        User user1 = new User();
24.        user1.setItems(new ArrayList<String>());
25.        user1.setName("shenbin");
26.        user1.addItem("Java Gossip");
27.        user1.addItem("Java Gossip");
28.        user1.addItem("Caxxx A80");
29.
30.        User user2 = new User();
31.        user2.setItems(new ArrayList<String>());
32.        user2.setName("chenyan");
33.        user2.addItem("Snoppy world");
34.
35.        Transaction tx = session.beginTransaction();
36.        session.save(user1);
37.        session.save(user2);
38.        tx.commit();
39.
40.
41.        session.close();
42.        sessionFactory.close();
43.    }
44.}

Bag是Hibernate自己提供的集合，他和Set的區別是它允許重復，他和List的區別是他不去管List容器中的順序。

然而，倘若要做下面的更新處理：

1.Session session = sessionFactory.openSession();
2.Transaction tx = session.beginTransaction();
3.User user = (User) session.load(User.class, new Integer(1));
4.user.removeItem("Java Gossip");
5.tx.commit();
6.session.close();

運行的SQL文為：

Hibernate: delete from item where id=? Hibernate: insert into item (id, name) values (?, ?) Hibernate: insert into item (id, name) values (?, ?)

由於Bag集合允許重復，當更新數據時，他無法知道需要更改的是重復數據中的哪比數據，所以采取全部刪除後重新寫入的方式。

然後，這顯然是種沒有效率的做法。

幸運的是，Hibernate提供idbag。借由在定義Bag映射時加上"collection-id"，讓Hibernate能確定需要更改的那條記錄從而提高效率。

新建表格：

1.CREATE TABLE user (
2.    id INT(11) NOT NULL auto_increment PRIMARY KEY,
3.    name VARCHAR(100) NOT NULL default ''
4.);
5.
6.CREATE TABLE item (
7.    cid CHAR(32) NOT NULL,
8.    id INT(11) NOT NULL,
9.    name VARCHAR(100) NOT NULL
10.);

改寫User.hbm.xml：

1.<?xml version="1.0" encoding="utf-8"?>
2.<!DOCTYPE hibernate-mapping
3.    PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
4.    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
5.
6.<hibernate-mapping>
7.
8.    <class name="com.hb3.pack_12.model.User" table="user">
9.
10.        <id name="id" column="id" type="java.lang.Integer">
11.            <generator class="native"/>
12.        </id>
13.
14.        <property name="name" column="name" type="java.lang.String"/>
15.
16.        <idbag name="items" table="item">
17.            <collection-id column="cid" type="java.lang.String">
18.                <generator class="uuid.hex"/>
19.            </collection-id>
20.            <key column="id"/>
21.            <element column="name" type="java.lang.String"/>
22.        </idbag>
23.
24.    </class>
25.
26.</hibernate-mapping>

測試代碼：

1.package com.hb3.pack_13;
2.
3.import java.io.IOException;
4.import java.sql.SQLException;
5.import java.util.ArrayList;
6.
7.import org.hibernate.Session;
8.import org.hibernate.SessionFactory;
9.import org.hibernate.Transaction;
10.import org.hibernate.cfg.Configuration;
11.
12.import com.hb3.pack_12.model.User;
13.
14.public class BusinessService {
15.
16.    public static void main(String[] args) throws IOException, SQLException {
17.
18.        Configuration config = new Configuration().configure();
19.        SessionFactory sessionFactory = config.buildSessionFactory();
20.        Session session = sessionFactory.openSession();
21.
22.
23.        User user1 = new User();
24.        user1.setItems(new ArrayList<String>());
25.        user1.setName("shenbin");
26.        user1.addItem("Java Gossip");
27.        user1.addItem("Java Gossip");
28.        user1.addItem("Caxxx A80");
29.
30.        User user2 = new User();
31.        user2.setItems(new ArrayList<String>());
32.        user2.setName("chenyan");
33.        user2.addItem("Snoppy world");
34.
35.        Transaction tx = session.beginTransaction();
36.        session.save(user1);
37.        session.save(user2);
38.        tx.commit();
39.
40.
41.        session.close();
42.        session = sessionFactory.openSession();
43.
44.
45.        tx = session.beginTransaction();
46.        User user = (User) session.load(User.class, new Integer(1));
47.        user.removeItem("Java Gossip");
48.        tx.commit();
49.
50.
51.
52.        session.close();
53.        sessionFactory.close();
54.    }
55.}

SQL文的Log:

13:32:16,187  WARN ConfigurationFactory:127 - No configuration found. Configuring ehcache from ehcache-failsafe.xml  found in the classpath: jar:file:/D:/Java/MyEclipse%206.0/workspace/hb3demo/ehcache-1.2.3.jar!/ehcache-failsafe.xml
13:32:16,609  WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.UpdateTimestampsCache]; using defaults.
13:32:16,640  WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.StandardQueryCache]; using defaults.
Hibernate: insert into user (name) values (?)
Hibernate: insert into user (name) values (?)
Hibernate: insert into item (id, cid, name) values (?, ?, ?)
Hibernate: insert into item (id, cid, name) values (?, ?, ?)
Hibernate: insert into item (id, cid, name) values (?, ?, ?)
Hibernate: insert into item (id, cid, name) values (?, ?, ?)
Hibernate: select user0_.id as id0_0_, user0_.name as name0_0_ from user user0_ where user0_.id=?
Hibernate: select items0_.id as id0_, items0_.name as name0_, items0_.cid as cid0_ from item items0_ where items0_.id=?
Hibernate: delete from item where cid=?

4.Map映射

DDL：

1.CREATE TABLE user (
2.    id INT(11) NOT NULL auto_increment PRIMARY KEY,
3.    name VARCHAR(100) NOT NULL default ''
4.);
5.
6.CREATE TABLE item (
7.    id INT(11) NOT NULL,
8.    name VARCHAR(100) NOT NULL,
9.    price decimal(10,2) NOT NULL
10.);

User.java

1.package com.hb3.pack_14.model;
2.
3.import java.math.BigDecimal;
4.import java.util.Map;
5.
6.public class User {
7.
8.    private Integer id;
9.    private String name;
10.    private Map<String, BigDecimal> items;
11.
12.    public User() {
13.    }
14.
15.    public Integer getId() {
16.        return id;
17.    }
18.    public void setId(Integer id) {
19.        this.id = id;
20.    }
21.    public String getName() {
22.        return name;
23.    }
24.    public void setName(String name) {
25.        this.name = name;
26.    }
27.    public Map<String, BigDecimal> getItems() {
28.        return items;
29.    }
30.    public void setItems(Map<String, BigDecimal> items) {
31.        this.items = items;
32.    }
33.    public void addItem(String key, BigDecimal value) {
34.        items.put(key, value);
35.    }
36.    public void removeItem(String key) {
37.        items.remove(key);
38.    }
39.}

User.hbm.xml：

1.<?xml version="1.0" encoding="utf-8"?>
2.<!DOCTYPE hibernate-mapping
3.    PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
4.    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
5.
6.<hibernate-mapping>
7.
8.    <class name="com.hb3.pack_14.model.User" table="user">
9.
10.        <id name="id" column="id" type="java.lang.Integer">
11.            <generator class="native"/>
12.        </id>
13.
14.        <property name="name" column="name" type="java.lang.String"/>
15.
16.        <map name="items" table="item">
17.            <key column="id"/>
18.            <map-key column="name" type="java.lang.String"/>
19.            <element column="price" type="java.math.BigDecimal"/>
20.        </map>
21.
22.    </class>
23.
24.</hibernate-mapping>

測試代碼：

1.package com.hb3.pack_14;
2.
3.import java.io.IOException;
4.import java.math.BigDecimal;
5.import java.sql.SQLException;
6.import java.util.HashMap;
7.
8.import org.hibernate.Session;
9.import org.hibernate.SessionFactory;
10.import org.hibernate.Transaction;
11.import org.hibernate.cfg.Configuration;
12.
13.import com.hb3.pack_14.model.User;
14.
15.
16.public class BusinessService {
17.
18.    public static void main(String[] args) throws IOException, SQLException {
19.
20.        Configuration config = new Configuration().configure();
21.        SessionFactory sessionFactory = config.buildSessionFactory();
22.        Session session = sessionFactory.openSession();
23.
24.
25.        User user1 = new User();
26.        user1.setItems(new HashMap<String, BigDecimal>());
27.        user1.setName("shenbin");
28.        user1.addItem("DC", new BigDecimal(100));
29.        user1.addItem("CF Card", new BigDecimal(80));
30.
31.        User user2 = new User();
32.        user2.setItems(new HashMap<String, BigDecimal>());
33.        user2.setName("chenyan");
34.        user2.addItem("CD", new BigDecimal(180));
35.
36.        Transaction tx = session.beginTransaction();
37.        session.save(user1);
38.        session.save(user2);
39.        tx.commit();
40.
41.
42.        session.close();
43.        sessionFactory.close();
44.    }
45.}

注意：正常運行代碼，需要修改hibernate.cfg.xml文件。

關於容器映射，還有如下說明。

1.內含 Component 的容器

DDL：

1.CREATE TABLE user (
2.    id INT(11) NOT NULL auto_increment PRIMARY KEY,
3.    name VARCHAR(100) NOT NULL default ''
4.);
5.
6.CREATE TABLE email (
7.    id INT(11) NOT NULL,
8.    address VARCHAR(100) NOT NULL
9.);

MailAddress.java

1.package com.hb3.pack_15.model;
2.
3.public class MailAddress {
4.
5.    private String address;
6.
7.    public MailAddress() {
8.    }
9.
10.    public String getAddress() {
11.        return address;
12.    }
13.    public void setAddress(String address) {
14.        this.address = address;
15.    }
16.
17.    public void sendMail() {
18.        System.out.println("Send mail to " + address);
19.    }
20.}

User.java

1.package com.hb3.pack_15.model;
2.
3.import java.util.Set;
4.
5.public class User {
6.
7.    private Integer id;
8.    private String name;
9.    private Set<MailAddress> emails;
10.
11.    public User() {
12.    }
13.
14.    public Integer getId() {
15.        return id;
16.    }
17.
18.    public void setId(Integer id) {
19.        this.id = id;
20.    }
21.
22.    public String getName() {
23.        return name;
24.    }
25.
26.    public void setName(String name) {
27.        this.name = name;
28.    }
29.
30.    public Set<MailAddress> getEmails() {
31.        return emails;
32.    }
33.
34.    public void setEmails(Set<MailAddress> emails) {
35.        this.emails = emails;
36.    }
37.
38.    public void addEmail(MailAddress mailAddress) {
39.        this.emails.add(mailAddress);
40.    }
41.
42.    public void removeEmail(MailAddress mailAddress) {
43.        this.emails.remove(mailAddress);
44.    }
45.}

User.hbm.xml：

1.<?xml version="1.0" encoding="utf-8"?>
2.<!DOCTYPE hibernate-mapping
3.    PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
4.    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
5.
6.<hibernate-mapping>
7.
8.    <class name="com.hb3.pack_15.model.User" table="user">
9.
10.        <id name="id" column="id" type="java.lang.Integer">
11.            <generator class="native" />
12.        </id>
13.
14.        <property name="name" column="name" type="java.lang.String" />
15.
16.        <set name="emails" table="email">
17.            <key column="id" />
18.            <composite-element class="com.hb3.pack_15.model.MailAddress">
19.                <property name="address" column="address"/>
20.            </composite-element>
21.        </set>
22.    </class>
23.</hibernate-mapping>

測試代碼：

1.package com.hb3.pack_15;
2.
3.import java.io.IOException;
4.import java.sql.SQLException;
5.import java.util.HashSet;
6.
7.import org.hibernate.Session;
8.import org.hibernate.SessionFactory;
9.import org.hibernate.Transaction;
10.import org.hibernate.cfg.Configuration;
11.
12.import com.hb3.pack_15.model.MailAddress;
13.import com.hb3.pack_15.model.User;
14.
15.
16.public class BusinessService {
17.
18.    public static void main(String[] args) throws IOException, SQLException {
19.
20.        Configuration config = new Configuration().configure();
21.        SessionFactory sessionFactory = config.buildSessionFactory();
22.        Session session = sessionFactory.openSession();
23.
24.
25.        User user = new User();
26.        user.setName("shenbin");
27.
28.        user.setEmails(new HashSet<MailAddress>());
29.        MailAddress mailAddress = new MailAddress();
30.        mailAddress.setAddress("[email protected]");
31.        user.addEmail(mailAddress);
32.
33.        mailAddress = new MailAddress();
34.        mailAddress.setAddress("[email protected]");
35.        user.addEmail(mailAddress);
36.
37.        Transaction tx = session.beginTransaction();
38.        session.save(user);
39.        tx.commit();
40.
41.
42.        session.close();
43.        sessionFactory.close();
44.    }
45.}
1.Session session = sessionFactory.openSession();
2.
3.User user = (User) session.load(User.class, new Integer(1));
4.Iterator iterator = user.getEmails().iterator();
5.while(iterator.hasNext()) {
6.    MailAddress mailAddress = (MailAddress) iterator.next();
7.    mailAddress.sendMail();
8.}
9.session.close();