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,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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