Creating Data Access Services

1
Creating Data Access Services

• Presented by
• Ashraf Memon

2
Overview

• Writing data access service classes in Java
• Generating service
• Deploying services with Apache Axis
• Generating client files and testing them

3
Writing data access service classes in Java

• Data Access Services in Java heavily depend on
  JDBC
• JDBC stands for Java Database Connectivity and is
  a industry standard Java API from Sun for talking
  to any database - depending on availability of
  database driver.

4
Writing data access service classes in Java
5
Writing data access service classes in Java

• Sample Data Access class contains 1 function,
  which reads coordinate data from summer_institute
  database and generates XML for it.
• Method signature is
• public String parse(int criteria)
• Complete class code follows

6
Writing Data Acess service classes in Java
(contd)

• import java.io.IOException
• import java.sql.SQLException
• import java.sql.Connection
• import java.sql.DriverManager
• import java.sql.Statement
• import java.sql.ResultSet
• public class DBAccess
• public DBAccess()

7
Writing Data Acess service classes in Java
(contd)

• public String parse(int criteria) throws
  IOException, SQLException,
• ClassNotFoundException
• String xml "lttablegt\r\n\t"
• Class.forName("com.mysql.jdbc.Driver")
• Connection connection DriverManager.getConne
  ction(
• "jdbcmysql//geon07.sdsc.edu3306/summer_
  institute", "root", "")
• Statement stmt connection.createStatement()
  

8
Writing Data Acess service classes in Java
(contd)
String sql "SELECT FROM earthquake WHERE
magnitude gt " Integer.toString(criteria)
ResultSet record stmt.executeQuery(sql)
while (record.next()) xml
"ltrecordgt\r\n\t\t" xml "ltlongt"
record.getString("longitude")
"lt/longt\r\n\t\t" xml "ltlatgt"
record.getString("latitude") "lt/latgt\r\n\t\t"
xml "ltmagnitudegt" record.getString("magn
itude") "lt/magnitudegt\r\n\t"
xml "lt/recordgt\r\n\t"

9
Writing Data Acess service classes in Java
(contd)
xml "\r\n" xml "lt/tablegt" return
xml

10
Generating Service

• Download DBAccessService directory from
  ftp//dotnet.sdsc.edu/CSIG-WS/
• Save directory to C\training\user\code
• Compile DBAccess.java file by typing following at
  command prompt
• javac DBAccess.java
• Run program by typing following at command prompt
• java DBAccess

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Generating Service (contd)

• Output should be
• lttablegt
• ltrecordgt
• ltlongt143.002lt/longt
• ltlatgt37.2850lt/latgt
• ltmagnitudegt2.25000E-02lt/magnitudegt
• lt/recordgt
• lt/tablegt

12
Deploying services with Apache Axis

• Copy generated class file to C\training\tools\tom
  cat\webapps\axis\WEB-INF\classes\
• Open deployDBAccess.wsdd in Textpad (Explanation
  by instructor)
• Close file.

13
Deploying services with Apache Axis(contd)

• Set classpath by typing classpath at command
  prompt
• Execute deployment descriptor by typing deploy
  deployDBAccess.wsdd at command prompt.
• This deploys webservice on Axis SOAP Server.

14
Generating client files and testing them(contd)

• Compile DBAccessServiceClient.java by typing
  following at command prompt
• javac DBAccessServiceClient.java
• Execute Client by typing following at command
  prompt
• java DBAccessServiceClient
• Output should be sinilar to execution of DBAccess