正确使用JDBC连接池（Glassfish） [英] Proper usage of JDBC Connection Pool (Glassfish)

问题描述

我需要将Java Web服务中的数据库连接作为会话bean实现，并且我不确定是否正确。

我创建了一个类

  public final class SQLUtils {
 // ..... 
 private static DataSource m_ds = null; 
 
 static 
 {
 try 
 {
 InitialContext ic = new InitialContext（）; 
 m_ds =（DataSource）ic.lookup（dbName）; //以前在Glassfish中创建的连接池和jdbc资源，dbName包含正确的JNDI资源名称
 
 $ b catch（Exception e）
 {
 e.printStackTrace ）; 
 m_ds = null; 
 
 
 
 $ b public static Connection getSQLConnection（）throws SQLException 
 {
 return m_ds.getConnection（）; 
 
 
  

每当我需要连接时，我都会这样做

  Connection cn = null; 
尝试
 {
 cn = SQLUtils.getSQLConnection（）; 
 //使用连接
} 
 finally 
 {
 if（null！= cn）
 {
 try 
 {
 cn.close（）; 
} 
 catch（SQLException e）
 {
 
} 
} 
} 
  

可以这样使用它，或者我的DataSource必须是bean的成员？

  @Stateless 
 @WebService 
 public class TestBean {
 private @Resource（name = dbName）DataSource m_ds; 
 
 $ / code $ / pre 
 
我很抱歉，如果它是一个nube问题，但我很漂亮Java新手。 
解决方案
除了C风格的格式化，一些不必要的行和有点差的异常处理，你可以
 
 
以下是我的做法： 
 
 
  public final class SQLUtil {
 private static DataSource dataSource; 
 // .. 
 
 static {
 try {
 dataSource =（DataSource）new InitialContext（）。lookup（name）; 
} catch（NamingException e）{
抛出新的ExceptionInInitializerError（e）; 
 
 
 
 public static Connection getConnection（）throws SQLException {
 return dataSource.getConnection（）; 
} 
} 
  
我在这里  ExceptionInInitializerError  ，这样应用程序将立即停止，以便您在尝试获取连接时无需面对无法解释 NullPointerException 。
 
I need a database connection in Java Web service implemented as a session bean, and I'm not sure if I do it right. 

I created a class 
public final class SQLUtils   {  
    //.....  
    private static DataSource  m_ds=null;    

    static  
    {  
        try
        {
            InitialContext ic = new InitialContext();
            m_ds = (DataSource) ic.lookup(dbName); //Connection pool and jdbc resource previously created in Glassfish  , dbName contains the proper JNDI resource name 

        }
        catch (Exception e)
        {
            e.printStackTrace();
            m_ds = null;
        }

    }

    public static Connection getSQLConnection() throws SQLException  
    {  
        return m_ds.getConnection();             
    }
}
Whenever I need a connection I do 
 Connection cn = null;  
 try  
 {
     cn = SQLUtils.getSQLConnection();
     // use connection
 }
 finally 
 {
     if (null != cn)
     {
         try
         {
             cn.close();
         }
         catch (SQLException e)
         {

         }
     }
 }
Is it ok to use it this way, or I DataSource must be a member of the bean ?
  @Stateless  
  @WebService  
  public class TestBean  {  
   private @Resource(name=dbName) DataSource m_ds;   
  }  
I'm sorry if it is a nube question, but I'm pretty new to Java. Thanks in advance.
解决方案
Apart from the C-style formatting, a few unnecessary lines and a bit poor exception handling, you can just do so.

Here's how I'd do it:
public final class SQLUtil {
    private static DataSource dataSource;
    // ..

    static {
        try {
            dataSource = (DataSource) new InitialContext().lookup(name);
        } catch (NamingException e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    public static Connection getConnection() throws SQLException {  
        return dataSource.getConnection();             
    }
}
I throw here ExceptionInInitializerError so that the application will immediately stop so that you don't need to face "unexplainable" NullPointerException when trying to obtain a connection.

                        
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