When DB2 is installed, the required drivers are automatically installed.
There are two ways of accessing the database:
By accessing a local DB2 Client Application Enabler
By accessing the DB2 server directly from a Java applet
The same design and code can be used in both cases, provided the programmer
is careful to parameterize the type of driver to load and the JDBC
connection URL's.
Using a local DB2 Client Application Enabler
This approach requires that the platform on which the Java application will
be run in a PC running Windows 95, NT or OS/2, or is some other platform on
which the DB2 Client can be installed - in other words, a thick client.
The required JDBC driver is located in the file \sqllib\java\db2java.zip
(on a Net.Commerce system this will be \ibm\sqllib\java\db2java.zip), and
this file must be included in the classpath environment variable. The
driver can be loaded and registered with the JDBC driver manager with the
line:
Class.forName("COM.ibm.db2.jdbc.app.DB2Driver");
This can be placed in a static initializer in the application. Systems
running OS/2 should use the form
Class.forName("COM.ibm.db2.jdbc.app.DB2Driver").newInstance();
Once this has been done, a database connection can be created:
con = DriverManager.getConnection("jdbc:db2:databasename, userid,
password);
The JDBC URL will take the form "jdbc:db2:databasename"
Access the DB2 Server Directly
With this approach, the client platform can be a PC or similar platform
running a browser, or it can be a Network Computer or similar thin client.
The JDBC driver is a pure Java driver, and loads across the network from a
web server running on the database server machine, in the case of an
applet.
The web server machine runs a JDBC server which accepts connections over
TCP/IP. You start the JDBC server with the command "db2jstrt portno". The
JDBC server, in turn, runs over the DB2 CLI (call level interface) which
can be provided by either a DB2 client or server. In the Net.Commerce
environment, the web server can be either running on the same machine as
the DB2 database server, or it can be on a separate machine, in which case
it will have the DB2 Client Application Enabler installed. Note that the
security model imposed by the sandbox of the Java Virtual Machine means
that a Java applet can basically only communicate with the server from
which it was loaded, which means that the JDBC driver must be running on
the same machine as the web server, rather than the database server.
The JDBC driver can be loaded and registered with the JDBC driver manager
with the line:
Class.forName("COM.ibm.db2.jdbc.net.DB2Driver");
or for OS/2 machines
Class.forName("COM.ibm.db2.jdbc.net.DB2Driver").newInstance();
In order for this to work, the JDBC driver must be downloadable from the
web server. This can be achieved by placing the db2java.zip file on the web
server, and using the archive= parameter of the APPLET HTML tag to specify
its location.
The JDBC URL will take the form "jdbc:db2://servername:port/databasename"
There are two ways of accessing the database:
By accessing a local DB2 Client Application Enabler
By accessing the DB2 server directly from a Java applet
The same design and code can be used in both cases, provided the programmer
is careful to parameterize the type of driver to load and the JDBC
connection URL's.
Using a local DB2 Client Application Enabler
This approach requires that the platform on which the Java application will
be run in a PC running Windows 95, NT or OS/2, or is some other platform on
which the DB2 Client can be installed - in other words, a thick client.
The required JDBC driver is located in the file \sqllib\java\db2java.zip
(on a Net.Commerce system this will be \ibm\sqllib\java\db2java.zip), and
this file must be included in the classpath environment variable. The
driver can be loaded and registered with the JDBC driver manager with the
line:
Class.forName("COM.ibm.db2.jdbc.app.DB2Driver");
This can be placed in a static initializer in the application. Systems
running OS/2 should use the form
Class.forName("COM.ibm.db2.jdbc.app.DB2Driver").newInstance();
Once this has been done, a database connection can be created:
con = DriverManager.getConnection("jdbc:db2:databasename, userid,
password);
The JDBC URL will take the form "jdbc:db2:databasename"
Access the DB2 Server Directly
With this approach, the client platform can be a PC or similar platform
running a browser, or it can be a Network Computer or similar thin client.
The JDBC driver is a pure Java driver, and loads across the network from a
web server running on the database server machine, in the case of an
applet.
The web server machine runs a JDBC server which accepts connections over
TCP/IP. You start the JDBC server with the command "db2jstrt portno". The
JDBC server, in turn, runs over the DB2 CLI (call level interface) which
can be provided by either a DB2 client or server. In the Net.Commerce
environment, the web server can be either running on the same machine as
the DB2 database server, or it can be on a separate machine, in which case
it will have the DB2 Client Application Enabler installed. Note that the
security model imposed by the sandbox of the Java Virtual Machine means
that a Java applet can basically only communicate with the server from
which it was loaded, which means that the JDBC driver must be running on
the same machine as the web server, rather than the database server.
The JDBC driver can be loaded and registered with the JDBC driver manager
with the line:
Class.forName("COM.ibm.db2.jdbc.net.DB2Driver");
or for OS/2 machines
Class.forName("COM.ibm.db2.jdbc.net.DB2Driver").newInstance();
In order for this to work, the JDBC driver must be downloadable from the
web server. This can be achieved by placing the db2java.zip file on the web
server, and using the archive= parameter of the APPLET HTML tag to specify
its location.
The JDBC URL will take the form "jdbc:db2://servername:port/databasename"
将db2的安装目录下：sqllib\java\db2java.zip加到你的classpath中。
thinkustc
2001-05-09