如何在hibernate中使用属性文件读取数据库配置参数

Question

在我的应用程序中,我使用hibernate,连接数据库并创建会话.这是我的hibernate.cfg.xml文件.还行吧.它运作正常.

<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>
        <!-- Database connection settings -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/country</property>
        <property name="connection.username">root</property>
        <property name="connection.password">password</property>

    </session-factory>

</hibernate-configuration>

但是当我尝试db.property file使用hibernate.cfg.xml它来读取数据库配置属性时,它显示了Exception,这是我的另一个hibernate.cfg.xml文件

<util:properties id="db" location="classpath:db.properties" />

<hibernate-configuration>

    <session-factory>
        <!-- Database connection settings -->
        <property name="driverClassName" value="#{db['driverClassName']}"></property>
        <property name="url" value="#{db['url']}"></property>
        <property name="username" value="#{db['username']}"></property>
        <property name="password" value="#{db['password']}"></property>

    </session-factory>

</hibernate-configuration>

这是错误

 org.dom4j.DocumentException: Error on line 8 of document  : The prefix "util" for       element "util:properties" is not bound. Nested exception: The prefix "util" for element   "util:properties" is not bound.
    at org.dom4j.io.SAXReader.read(SAXReader.java:482)
    at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:2155)

这是我的名为的属性文件 db.properties

driverClassName=com.mysql.jdbc.Driver

url=jdbc:mysql://localhost:3306/country

username=root

password=password

有什么问题？如何正确地做到这一点

Answer 1

util:properties不是在hibernate.cfg.xml文件中使用的有效标记.如果要将所有数据库配置详细信息放在属性文件中,则可以将它们放在hibernate.properties文件中并从hibernate.cfg.xml文件中删除它们.这样,DB详细信息将在属性文件中维护.

如果您想维护一个单独的文件而不是使用hibernate.properties文件,那么您可以尝试这样做:

java.util.Properties properties = new Properties();
properties.load(new FileInputStream("db.properties"));

Configuration configuration = new Configuration();

configuration.configure("hibernate.cfg.xml").addProperties(properties);;

ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
.applySettings(configuration.getProperties()).build();

SessionFactory sessionFactory = configuration
.buildSessionFactory(serviceRegistry);

Answer 2

试试这个代码：

hibernate.properties

hibernate.connection.url=jdbc:mysql://localhost:3306/country
hibernate.connection.driver_class=com.mysql.jdbc.Driver
hibernate.connection.username=root
hibernate.connection.password=123

HibernateUtil.java

import java.util.Properties;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;

public class HibernateUtil {

private static final SessionFactory sessionFactory = buildSessionFactory();

private static SessionFactory buildSessionFactory() {
    try {

        Properties dbConnectionProperties = new Properties();
        try {
            dbConnectionProperties.load(HibernateUtil.class.getClassLoader().getSystemClassLoader().getResourceAsStream("hibernate.properties"));
        } catch(Exception e) {
            e.printStackTrace();
            // Log
        }           

        return new AnnotationConfiguration().mergeProperties(dbConnectionProperties).configure("hibernate.cfg.xml").buildSessionFactory();          


    } catch (Throwable ex) {
        ex.printStackTrace();
//            throw new ExceptionInInitializerError(ex);
    }
    return null;
}

public static SessionFactory getSessionFactory() {
    return sessionFactory;
}

}

休眠文件.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>

    <!-- Database connection settings -->

    <!-- JDBC connection pool (use the built-in) -->
    <property name="connection.pool_size">1</property>

    <!-- SQL dialect -->
     <property name="dialect">org.hibernate.dialect.MySQLDialect</property> 

    <!-- Enable Hibernate's automatic session context management -->
    <property name="current_session_context_class">thread</property>

    <!-- Disable the second-level cache  -->
    <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

    <!-- Echo all executed SQL to stdout -->
    <property name="show_sql">false</property>

    <property name="hibernate.hbm2ddl.auto">update</property>
    <!--<mapping class="net.viralpatel.hibernate.Employee"/>-->
    <!--<mapping class="net.viralpatel.hibernate.PersonEntity"/>-->
    <mapping class="mobin.FavaEmail.entities.PersonEntity"/>
    <mapping class="mobin.FavaEmail.entities.OrgEntity"/>
    <mapping class="mobin.FavaEmail.entities.User"/>


</session-factory>
</hibernate-configuration>