In the given example of Enterprise Java Bean, we are
going to delete a row from the SQL Table. Find out the steps given below that describes
how to delete a particular row from the database table using EJB. The steps involved
in this process are as :-
1)Create an interface named AccountStatusRemote.java
AccountStatusRemote.java :-This is the Remote Interface for the
Bean. Here we have used @Remote annotation to declare the class as
a Remote Interface. The use of annotation here is that through it we
can create a java source file which contain the bean implementation logic.
String getStatus(); String getAddress(); String getUpdate();:-These
are the method which is to be defined in the Bean and is called in the client
application.
AccountStatusRemote.java
package bean;
import javax.ejb.Remote;
import java.util.*;
@Remote
public interface AccountStatusRemote {
String getStatus();
String getAddress();
String getUpdate();
}
|
2)Create a Bean named AccountStatusBean.java
AccountStatusBean.java:-This is the session bean
we have created. By session bean we mean the bean which act as an agents to the
client. it is generally used in controlling the business process and filling the
gaps between the data of the entity beans. Here
@Stateless is the session type.
@RolesAllowed(value = {"USERS"}):-This is also the
annotation which means that only users in the security role USERS can access the
method declared in the Bean .
Main.java:-This is the client application
through which we can access the methods which are defined in the bean.
@EJB:-This is the annotation that configure the
EJB values for a field or a method. Normally this annotation is a Resource
annotation where it is known that the resultant is an EJB interface.
private static AccountStatusRemote accountStatusBean:-By
this we have created an instance of the interface AccountStatusRemote .
AccountStatusBean.java
package bean;
import java.sql.*;
import java.util.*;
import javax.annotation.security.RolesAllowed;
import javax.ejb.Stateless;
@Stateless
public class AccountStatusBean implements AccountStatusRemote {
private String name = "Roseindia.net";
private String address = "sec-3,D-16/116,Rohini";
private String Update;
@RolesAllowed(value = {"USERS"})
public String getStatus() {
return "Name of the company is: " + name;
}
public String getAddress() {
return "Address of the company is: " + address;
}
@SuppressWarnings(value = "unchecked")
public String getUpdate() {
Connection con = null;
String url = "jdbc:mysql://192.168.10.75:3306/";
String dbName = "komal";
String driver = "com.mysql.jdbc.Driver";
String updateString=null;
String userName = "root";
String password = "root";
try {
Class.forName(driver).newInstance();
con = DriverManager.getConnection(url + dbName, userName, password);
Statement st = con.createStatement();
updateString="delete from employees where First_Name='A'";
st.executeUpdate(updateString);
st.close();
} catch (Exception e) {
}
return updateString ;
}
}
|
Output of the program
Name of the company is: Roseindia.net
Address of the company is: sec-3,D-16/116,Rohini
=====================================
Data updated successfully : See sql table to verify
delete from employees where First_Name='A' |
Download Source code
Del.icio.us
Digg
Google
Spurl
Blink
Furl
Simpy
Y! MyWeb
