当前线程中存放变量

这是一个简单的示例，代码并不完整，不能正确产生数据库连接，只不过是为了演示一下，如何在当前线程中构建并保存一个变量对象及从如何当前线程中获取之前构建的变量。其适用的场景之一是：在一个地方创建这个对象，在另一个地方使用这个对象，中间并不需要将这个对象做为参数传递。
import java.sql.Connection;
import javax.sql.DataSource;
import org.apache.commons.dbcp.BasicDataSource;
import org.apache.log4j.Logger;
public class MyConnectionFactory {

private ThreadLocal thread = new ThreadLocal();
private static MyConnectionFactory instance=new  MyConnectionFactory();
public static Connection createConnection() {

ThreadLocal thread = instance.thread;
Object objConn = thread.get();
if (objConn == null) {
Connection conn = null;
try {

DataSource ds = (DataSource) obj;
conn = ds.getConnection();

thread.set(conn);
} catch (SQLException e) {

}
}
return (Connection) threadConn.get();
}


public static Connection getConnection() {
Object objConn = instance.thread.get();

Connection conn = (Connection) objConn;
return conn;
}


public static void commit(){
Object objConn = instance.thread.get();
Connection conn = (Connection) objConn;
try {
conn.commit();
} catch (SQLException e) {

}
}
}