运行时修改hibernate.cfg.xml [英] hibernate.cfg.xml modification on runtime

问题描述

我有这个问题，有些人已经解决了，但问题是我不明白我的实现中缺少什么。

部分hibernate代码如下所示：

 < hibernate-configuration> 
< session-factory> 
< property name =hibernate.dialect> org.hibernate.dialect.PostgreSQLDialect< / property> 
< property name =hibernate.connection.driver_class> org.postgresql.Driver< / property> 
< property name =hibernate.connection.url> jdbc：postgresql：// localhost：5432 / Database< / property> 
< property name =hibernate.connection.username>用户名< / property> 
< property name =hibernate.connection.password>密码< / property> 
  

事情是我想选择我想在运行时使用的数据库，方法是更改hibernate.connection.url属性中的数据库字。

在javaswing中，我正在实现此功能：

  public static void SetSessionFactory（String url）{
 try {
 
 AnnotationConfiguration conf = new AnnotationConfiguration（）。configure（）; 
 //<！ - 数据库连接设置 - > 
 conf.setProperty（hibernate.connection.url，url）; 
 SessionFactory SESSION_FACTORY = conf.buildSessionFactory（）; 
 
 // DEBUG1 =有了这个输出，我打算检查参数是否已经改变
 System.out.println（Connection changed to+ conf.getProperty（hibernate.connection.url ））; 
 
} catch（Throwable ex）{
 //记录异常！ 
抛出新的ExceptionInInitializerError（ex）; 
} 
  

}

然后，我检查使用按钮所做的更改，从组合框中选择我想要的数据库：

  private void jButton2ActionPerformed（java .awt.event.ActionEvent evt）{
 // TODO在这里添加您的处理代码：
 String url; 
 int areaIndex = this.areaComboBox.getSelectedIndex（）; 
 
 switch（areaIndex）{
 case 0：
 url =jdbc：postgresql：// localhost：5432 / Database; 
休息; 
案例1：
 url =jdbc：postgresql：// localhost：5432 / Database1; 
休息; 
案例2：
 url =jdbc：postgresql：// localhost：5432 / Database2; 
休息; 
默认值：
 url =jdbc：postgresql：// localhost：5432 / Database; 
休息; 
} 
 SetSessionFactory（url）; 
 
 AnnotationConfiguration config = new AnnotationConfiguration（）。configure（）; 
 // DEBUG2 =有了这个输出，我想确认setSessionFactory函数之外的属性更改
 System.out.println（DATABASE =+ config.getProperty（hibernate.connection.url ））; 
 
 $ / code> 

现在，debug1的输出正在改变，所以我得到这个print我想要的数据库的名称，但debug2的输出没有改变。不用说，我的代码的其余部分可以访问未更改的数据库，而不是我想要从运行时访问的数据库。

如何修改此在运行时的值？

非常感谢！

解决方案

I找到了解决我的问题的方法。问题是，当我想在其余代码中使用新配​​置时，我无法做到这一点，因为每次事务我都打开一个新会话（按照hibernate的建议），但那个会话总是那个在hibernate.cfg.xml文件的开头。另外，我在一个按钮中定义了我的配置功能。

现在我改变了我的函数的位置并将它放在HibernateUtil.java中，只添加了我需要的配置以及稍后可能会用到的配置

  public static void SetSessionFactory（String url，String user，String pass）{
 try {
 
 AnnotationConfiguration conf = new AnnotationConfiguration（）。configure（）; 
 //<！ - 数据库连接设置 - > 
 conf.setProperty（hibernate.connection.url，url）; 
 conf.setProperty（hibernate.connection.username，user）; 
 conf.setProperty（hibernate.connection.password，pass）; 
 sessionFactory = conf.buildSessionFactory（）; 
 
} catch（Throwable ex）{
 //记录异常！ 
抛出新的ExceptionInInitializerError（ex）; 
} 
} 
  

然后，任何时候我想访问那个新的连接，在我调用会话的每个事务开始时指向同一个类HibernateUtil.java

  public Session session = 。HibernateUtil.getSessionFactory（）的openSession（）; 
  

没有在这个类中放置第一个函数，正在打开的会话总是那个默认情况下在配置文件中。

I have this question that some people have already solved, but the thing is I don't understand what is missing in my implementation.

Part of my hibernate code is as follows:

<hibernate-configuration>
  <session-factory>
    <property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
    <property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
    <property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/Database</property>
    <property name="hibernate.connection.username">username</property>
    <property name="hibernate.connection.password">password</property>

the thing is that I want to select the database that I want to use in the runtime, by changing the "database" word in the hibernate.connection.url property.

In javaswing, I'm implementing this function:

public static void SetSessionFactory(String url) {
    try {

  AnnotationConfiguration conf = new AnnotationConfiguration().configure();
   // <!-- Database connection settings -->
  conf.setProperty("hibernate.connection.url", url);
  SessionFactory SESSION_FACTORY = conf.buildSessionFactory();

  //DEBUG1=With this output I intend to check if the parameter has changed
  System.out.println("Connection changed to " + conf.getProperty("hibernate.connection.url"));

} catch (Throwable ex) {
  // Log exception!
  throw new ExceptionInInitializerError(ex);
}

}

Then, I check the changes made with a button, selecting the database that I want from a combobox:

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
       String url;
        int areaIndex = this.areaComboBox.getSelectedIndex();

      switch (areaIndex) {
        case 0:
            url="jdbc:postgresql://localhost:5432/Database";
            break;
        case 1:
            url="jdbc:postgresql://localhost:5432/Database1";
            break;
        case 2:
            url="jdbc:postgresql://localhost:5432/Database2";
            break;
        default:
            url="jdbc:postgresql://localhost:5432/Database";
            break;
    }
    SetSessionFactory(url);   

  AnnotationConfiguration config = new AnnotationConfiguration().configure();
  //DEBUG2= With this output I want to confirm the changes of the property outside the setSessionFactory function
   System.out.println("DATABASE= " + config.getProperty("hibernate.connection.url"));
}  

Now, the output of the debug1 is changing, so I get in this print the name of the database that I want, but the output of the debug2 is not changing. Needless to say that the rest of my code have access to the unchanged database, not the one that I want to access from the runtime.

How can I get to modify this value on the runtime?

Thanks a lot!

解决方案

I found a way to solve my issue. The thing is that when I wanted to use the new configuration in the rest of the code I couldn't, 'cause for each transaction I opened a new session (as recommended by hibernate), but the that session was always the one that was at the beginning of the hibernate.cfg.xml file. Also, I was defining my configuration function in one button.

Now I changed the position of my function and put it in HibernateUtil.java, adding just the configurations that I needed and some that could be useful later

public static void SetSessionFactory(String url, String user, String pass) {
    try {

      AnnotationConfiguration conf = new AnnotationConfiguration().configure();
      // <!-- Database connection settings -->
      conf.setProperty("hibernate.connection.url", url);
      conf.setProperty("hibernate.connection.username", user);
      conf.setProperty("hibernate.connection.password", pass);
      sessionFactory = conf.buildSessionFactory();

    } catch (Throwable ex) {
      // Log exception!
      throw new ExceptionInInitializerError(ex);
    }
  }

And then, any time that I want to access to that new connection, at the beginning of each transaction I call the session pointed to the same class HibernateUtil.java

public Session session = HibernateUtil.getSessionFactory().openSession();

Without putting the first function in this class, the session that was being opened was always the one that was by default in the configuration file.

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