Hibernate5 动态模型

package com.pap.jpa.constant;
import org.hibernate.SessionFactory;import org.hibernate.boot.Metadata;import org.hibernate.boot.MetadataSources;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.id.IdentifierGenerator;import org.hibernate.internal.SessionFactoryImpl;import org.hibernate.service.ServiceRegistry;import org.hibernate.tool.hbm2ddl.SchemaUpdate;import org.hibernate.tool.schema.TargetType;import org.springframework.orm.hibernate5.LocalSessionFactoryBean;
import javax.persistence.EntityManager;import javax.sql.DataSource;import java.io.ByteArrayInputStream;import java.util.*;
/** * LocalSessionFactoryBean * * */public class LocSessFacBeanConstant {
    /**     * 存储动态添加的 LocalSessionFactoryBean 信息， 每一个动态模型对应一个 Map。     */    public static final List<Map<String, SessionFactory>> locSessFacBeanList = new ArrayList<Map<String, SessionFactory>>();
    /**     * 获取 SessionFactory      * @param entityManager     * @param dataSource     * @param entityName     * @param XML_MAPPING     * @return     * @throws Exception     */    public static SessionFactory get(EntityManager entityManager, DataSource dataSource, String entityName, String XML_MAPPING) throws Exception {        SessionFactory sessionFactory = entityManager.getEntityManagerFactory().unwrap(SessionFactory.class);//        ClassMetadata classMetadata = sessionFactory.getClassMetadata(entityName);//        String[] propertyNames = classMetadata.getPropertyNames();
        IdentifierGenerator identifierGenerator = ((SessionFactoryImpl) sessionFactory).getIdentifierGenerator(entityName);        if(identifierGenerator != null) {            return sessionFactory;        } else {            for(Map<String, SessionFactory> localSessionFactoryBeanMap : LocSessFacBeanConstant.locSessFacBeanList) {                if(localSessionFactoryBeanMap.containsKey(entityName)) {                    return localSessionFactoryBeanMap.get(entityName);                }            }
            LocalSessionFactoryBean localSessionFactoryBean = new LocalSessionFactoryBean();            localSessionFactoryBean.setDataSource(dataSource);            localSessionFactoryBean.afterPropertiesSet();
            Configuration configuration = localSessionFactoryBean.getConfiguration();            ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
            MetadataSources metadataSources = new MetadataSources(serviceRegistry);            //读取映射文件            metadataSources.addInputStream(new ByteArrayInputStream(XML_MAPPING.getBytes()));            Metadata metadata = metadataSources.buildMetadata();            //更新数据库Schema,如果不存在就创建表,存在就更新字段,不会影响已有数据            SchemaUpdate schemaUpdate = new SchemaUpdate();            schemaUpdate.execute(EnumSet.of(TargetType.DATABASE), metadata, serviceRegistry);
            //合并配置            configuration.addInputStream(new ByteArrayInputStream(XML_MAPPING.getBytes()));            SessionFactory newSessionFactory = configuration.buildSessionFactory(serviceRegistry);
            Map<String, SessionFactory> tmp = new HashMap<>();            tmp.put(entityName, newSessionFactory);            locSessFacBeanList.add(tmp);
            return newSessionFactory;        }
    }}

package com.pap.jpa.controller;
import com.pap.jpa.constant.LocSessFacBeanConstant;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RestController;
import javax.persistence.EntityManager;import javax.persistence.Query;import javax.servlet.http.HttpServletRequest;import javax.sql.DataSource;import java.util.*;import java.util.List;import java.util.Map;
@RestControllerpublic class TestController {
    @Autowired    private EntityManager entityManager;
    @Autowired    private DataSource dataSource;
    /**     * 运行期的持久化实体没有必要一定表示为像POJO类或JavaBean对象那样的形式。     * Hibernate也支持动态模型在运行期使用Map和象DOM4J的树模型那样的实体表示。     * 使用这种方法，你不用写持久化类，只写映射文件就行了。     **/    public static final String XML_MAPPING = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +            "<!DOCTYPE hibernate-mapping PUBLIC\n" +            "        \"-//Hibernate/Hibernate Mapping DTD 3.0//EN\"\n" +            "        \"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd\">\n" +            "<hibernate-mapping>\n" +            "    <class entity-name=\"Student\" table=\"t_student\">\n" +            "        <id name=\"id\" type=\"java.lang.Long\" length=\"64\" unsaved-value=\"null\">\n" +            "            <generator class=\"identity\" />\n" +            "        </id>" +            "        <property type=\"java.lang.String\" name=\"userName\" column=\"userName\"/>\n" +            "        <property name=\"age\" type=\"java.lang.Integer\" column=\"age\"/>\n" +            "    </class>" +            "</hibernate-mapping>";

    @GetMapping("/test")    public void test(HttpServletRequest request) {        try {            SessionFactory newSessionFactory = LocSessFacBeanConstant.get(entityManager, dataSource, "Student", XML_MAPPING);            //保存对象            Session newSession = newSessionFactory.openSession();
            Map<String, Object> student = new HashMap<>();            student.put("userName", "alexgaoyh");            student.put("sex", "male");            newSession.save("Student", student);                        //查询所有对象            Query query = newSession.createQuery("from Student");            List list = query.getResultList();
            newSession.close();
        } catch (Exception e) {            e.printStackTrace();        }    }
}