Designing and Developing WS

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Designing and Developing WS

• B. Ramamurthy

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Plans

• We will examine the resources available for
  development of JAX-WS based web services.
• We need an IDE, integrated development
  environment. It simplifies the development while
  providing tools for debugging and testing etc.
• Today we will work with netbeans (you are free to
  work with Eclipse or another IDE if you have
  invested time in learning an environment in your
  earlier classes.)

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Get started

• www.netbeans.org
• Version6.0 , 5.5.x are fine
• I will work with version 5.5.1 tutorials
• We will look at JAX-WS develop, deploy and test
  cycle

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Netbeans IDE

• Netbeans is a comprehensive IDE for
  enterprise/server side Java development.
• Lets examine the various regions of the Netbeans
  IDE.

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Netbeans5.5

• Top line menu (File, Build, Run, Window are
  commonly used).
• Source editor area on the right.
• Project files/folder explorer area on the left.
• Input/output area at the bottom.
• Runtime (Window?Runtime)

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Netbeans IDE

• Examine the various tools/tabs provided by the
  IDE.
• Setup and configure the server (it comes with a
  bundled Tomcat server).
• You will be deploying the webservice in this
  server.

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Working with Oracle

• Use the Oracle DBMS on CSE machines. Information
  about this is available here.
• You can access csedb from your laptop as long you
  have enabled VPN and installed the appropriate
  driver and connected the data source. (and of
  course you have an internet connectivity).
• jdbcoraclethin_at_oraserve.cse.buffalo.edu1521c
  sedb
• The driver is available here.

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Standard Access to DB
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ODBC Architecture
Application
Class1
Class2
ODBC
Driver Manager
DataSource3
DataSource2
DataSource1
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Open Database Connectivity (ODBC) Standard

• ODBC standard is an interface by which
  application programs can access and process SQL
  databases in a DBMS-independent manner. It
  contains
• A Data Source that is the database, its
  associated DBMS, operating system and network
  platform
• A DBMS Driver that is supplied by the DBMS vendor
  or independent software companies
• A Driver Manager that is supplied by the vendor
  of the O/S platform where the application is
  running

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ODBC Interface

• It is a system independent interface to database
  environment that requires an ODBC driver to be
  provided for each database system from which you
  want to manipulate data.
• The database driver bridges the differences
  between your underlying system calls and the ODBC
  interface functionality.

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An Example
odbc standard API
Application
DriverManager
Access driver
mySQL driver
Oracle driver
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Application in Java
odbc standard API
jdbc API
Application in Java
DriverManager
Sybase driver
mSQL driver
Informix driver
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Java Support for ODBC JDBC

• When applications written in Java want to access
  data sources, they use classes and associated
  methods provided by Java DBC (JDBC) API.
• JDBC is specified an an interface.
• An interface in Java can have many
  implementations.
• So it provides a convenient way to realize many
  drivers

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Java Support for SQL

• Java supports embedded SQL.
• Also it provides an JDBC API as a standard way to
  connect to common relational databases.
• Java.sql package and an extensive exception
  hierarchy.

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Data Source

• Local relational database Ex Oracle
• Remote relational database on a server Ex
  InfoSource
• On-line information service Ex Dow Jones,
  Customer database

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SQL Statements

• SELECT what FROM table name
• SELECT what FROM table name WHERE criteria
• SELECT what FROM table name WHERE criteria
  ORDER BY field
• Others
• Queries are embedded as strings in a Statement
  object.

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JDBC Components

• Driver Manager Loads database drivers, and
  manages the connection between application
  driver.
• Driver Translates API calls to operations for a
  specific data source.
• Connection A session between an application and
  a driver.
• Statement A SQL statement to perform a query or
  an update operation.
• Metadata Information about the returned data,
  driver and the database.
• Result Set Logical set of columns and rows
  returned by executing a statement.

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JDBC Classes

• Java supports DB facilities by providing classes
  and interfaces for its components
• DriverManager class
• Connection interface (abstract class)
• Statement interface (to be instantiated with
  values from the actual SQL statement)
• ResultSet interface

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Driver Manager Class

• Provides static, factory methods for creating
  objects implementing the connection interface.
• Factory methods create objects on demand
• When a connection is needed to a DB driver,
  DriverManager does it using it factory methods.

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Connection interface

• Connection class represents a session with a
  specific data source.
• Connection object establishes connection to a
  data source, allocates statement objects, which
  define and execute SQL statements.
• Connection can also get info (metadata) about the
  data source.

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Statement interface

• Statement interface is implemented by the
  connection object.
• Statement object provides the workspace for SQL
  query, executing it, and retrieving returned
  data.
• Types Statement, PreparedStatement,
  CallableStatement

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ResultSet interface

• Results are returned in the form of an object
  implementing the ResultSet interface.
• You may extract individual columns, rows or cell
  from the ResultSet using the metadata.

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JDBC Application Architecture
Application
Result Set
Connection
Statement
Driver Manager
DataSource
DataSource
DataSource
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JDBC Programming Steps

• Import necessary packages Ex import java.sql.
• Include jdbc classes as a jar library.
• Connect to the data source using identifying
  string , a user name and password.
• Allocate Connection object, Statement object and
  ResultSet object
• Execute query using Statement object
• Retrieve data from ResultSet object
• Close Connection object.

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Identifying Data Sources

• It is specified using URL format.
• ltschemegt ltsub_schemegtltscheme-specific-partgt
• Example(for local source) jdbcodbctech_books
• Alternatively, for remote connection,
• jdbcodbcthin_at_oraserve.cse.buffalo.edu1521csedb

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Connecting to a database on Netbeans

1. Add the driver jar file to the library for
   inclusion during compiling and building of the
   executable.
2. Add a new driver (jdbcodbc) to the databases
   tab.
3. Open connection to the data source (in this case
   to an Oracle 9i instance)
4. On successful connection you can view the data
   source details (tables etc.).
5. You can programmatically access the content of
   the database from a Java program.
6. You can execute SQL command from the source
   editor window.