使用xml文件的Hibernate Mapping Map HibernateMappingMap|Hibernate

Hibernate允许你使用RDBMS映射Map元素。众所周知, 列表和映射是基于索引的集合。对于map, 索引列用作键, 元素列用作值。
使用xml文件的集合映射中的映射映射示例
你需要创建以下页面来映射地图元素。

Question.java
question.hbm.xml
hibernate.cfg.xml
StoreTest.java
FetchTest.java

Question.java

package com.srcmini; import java.util.Map; public class Question { private int id; private String name, username; private Map< String, String> answers; public Question() {} public Question(String name, String username, Map< String, String> answers) { super(); this.name = name; this.username = username; this.answers = answers; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public Map< String, String> getAnswers() { return answers; } public void setAnswers(Map< String, String> answers) { this.answers = answers; } }

question.hbm.xml

< ?xml version='1.0' encoding='UTF-8'?> < !DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 5.3//EN" "http://hibernate.sourceforge.net/hibernate-mapping-5.3.dtd"> < hibernate-mapping> < class name="com.srcmini.Question" table="question736"> < id name="id"> < generator class="native"> < /generator> < /id> < property name="name"> < /property> < property name="username"> < /property> < map name="answers" table="answer736" cascade="all"> < key column="questionid"> < /key> < index column="answer" type="string"> < /index> < element column="username" type="string"> < /element> < /map> < /class> < /hibernate-mapping>

hibernate.cfg.xml

< ?xml version='1.0' encoding='UTF-8'?> < !DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 5.3//EN" "http://hibernate.sourceforge.net/hibernate-configuration-5.3.dtd"> < hibernate-configuration> < session-factory> < property name="hbm2ddl.auto"> update< /property> < property name="dialect"> org.hibernate.dialect.Oracle9Dialect< /property> < property name="connection.url"> jdbc:oracle:thin:@localhost:1521:xe< /property> < property name="connection.username"> system< /property> < property name="connection.password"> jtp< /property> < property name="connection.driver_class"> oracle.jdbc.driver.OracleDriver< /property> < mapping resource="question.hbm.xml"/> < /session-factory> < /hibernate-configuration>

StoreTest.java

package com.srcmini; import java.util.HashMap; import org.hibernate.*; import org.hibernate.boot.Metadata; import org.hibernate.boot.MetadataSources; import org.hibernate.boot.registry.StandardServiceRegistry; import org.hibernate.boot.registry.StandardServiceRegistryBuilder; public class StoreTest { public static void main(String[] args) { StandardServiceRegistry ssr=new StandardServiceRegistryBuilder().configure("hibernate.cfg.xml").build(); Metadata meta=new MetadataSources(ssr).getMetadataBuilder().build(); SessionFactory factory=meta.getSessionFactoryBuilder().build(); Session session=factory.openSession(); Transaction t=session.beginTransaction(); HashMap< String, String> map1=new HashMap< String, String> (); map1.put("Java is a programming language", "John Milton"); map1.put("Java is a platform", "Ashok Kumar"); HashMap< String, String> map2=new HashMap< String, String> (); map2.put("Servlet technology is a server side programming", "John Milton"); map2.put("Servlet is an Interface", "Ashok Kumar"); map2.put("Servlet is a package", "Rahul Kumar"); Question question1=new Question("What is Java?", "Alok", map1); Question question2=new Question("What is Servlet?", "Jai Dixit", map2); session.persist(question1); session.persist(question2); t.commit(); session.close(); System.out.println("successfully stored"); } }

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【使用xml文件的Hibernate Mapping Map】FetchTest.java

package com.srcmini; import java.util.*; import javax.persistence.TypedQuery; import org.hibernate.*; import org.hibernate.boot.Metadata; import org.hibernate.boot.MetadataSources; import org.hibernate.boot.registry.StandardServiceRegistry; import org.hibernate.boot.registry.StandardServiceRegistryBuilder; public class FetchTest { public static void main(String[] args) { StandardServiceRegistry ssr=new StandardServiceRegistryBuilder().configure("hibernate.cfg.xml").build(); Metadata meta=new MetadataSources(ssr).getMetadataBuilder().build(); SessionFactory factory=meta.getSessionFactoryBuilder().build(); Session session=factory.openSession(); TypedQuery query=session.createQuery("from Question "); List< Question> list=query.getResultList(); Iterator< Question> iterator=list.iterator(); while(iterator.hasNext()){ Question question=iterator.next(); System.out.println("question id:"+question.getId()); System.out.println("question name:"+question.getName()); System.out.println("question posted by:"+question.getUsername()); System.out.println("answers....."); Map< String, String> map=question.getAnswers(); Set< Map.Entry< String, String> > set=map.entrySet(); Iterator< Map.Entry< String, String> > iteratoranswer=set.iterator(); while(iteratoranswer.hasNext()){ Map.Entry< String, String> entry=(Map.Entry< String, String> )iteratoranswer.next(); System.out.println("answer name:"+entry.getKey()); System.out.println("answer posted by:"+entry.getValue()); } } session.close(); } }

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