JSP Client of an Enterprise Bean
<jsp:useBean id="accountBean" scope="session" class="AccountBean" />
<jsp:setProperty name="accountBean" property="*" />
<%! String status; %>
<% status = accountBean.processRequest(); %>
<html>
<head>
<title>Account JSP</title>
</head>
<body background="back.gif">
<font size = 5 color="#CC0000">
<h1><b><center>Account JSP Example</center></b></h1>
<hr>
<br>
<form method=POST action=Account.jsp>
<BR>
<br>Account ID <INPUT type=text name="id" size="8" value="<jsp:getProperty name="accountBean" property="id" />" >
Balance <INPUT type=text name="balance" size="8" value="<jsp:getProperty name="accountBean" property="balance" />" ><br>
First Name <INPUT type=text name="firstName" size="8" value="<jsp:getProperty name="accountBean" property="firstName" />">
Last Name <INPUT type=text name="lastName" "size=8" Value="<jsp:getProperty name="accountBean" property="lastName" />" ><br> <br>
<h2><b>Action :</b></h2>
<INPUT type="radio" name="action" value="create">Create
<INPUT type="radio" name="action" value="find">Find
<INPUT type="radio" name="action" value="debit">Debit
<INPUT type="radio" name="action" value="credit">Credit
<br>
<br>Amount <INPUT type=text name="amount"><br>
<INPUT type=submit name="submit" value="Submit">
</form>
</FONT>
</body>
</html>
<hr>
<h3><b>Status :</b></h3> <%= status %>
</html>
import java.io.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;
public class AccountBean {
private String action;
private String id;
private String firstName;
private String lastName;
private double balance;
private double amount;
private AccountHome accountHome;
private Account account;
public AccountBean() {
try {
Context ic = new InitialContext();
java.lang.Object objref = ic.lookup("java:comp/env/ejb/Account");
accountHome = (AccountHome) PortableRemoteObject.narrow(objref, AccountHome.class);
System.out.println("obtained accountHome object");
} catch (Exception re) {
System.err.println ("Couldn't locate Account Home");
re.printStackTrace();
}
reset();
}
public String processRequest() {
String message = "";
System.out.println("Process request called ");
System.out.println(this);
try {
if( action.equals("create") ) {
account =
accountHome.create(id, firstName, lastName, balance);
message = "Created account '" + id + "'";
}
else if( action.equals("debit") ) {
account = accountHome.findByPrimaryKey(id);
account.debit(amount);
loadFromEJB();
message = "Debited account '" + id + "' by $" + amount;
}
else if( action.equals("credit") ) {
account = accountHome.findByPrimaryKey(id);
account.credit(amount);
loadFromEJB();
message = "Credited account '" + id + "' by $" + amount;
}
else if( action.equals("find") ) {
account = accountHome.findByPrimaryKey(id);
loadFromEJB();
message = "Found account '" + id;
}
} // try
catch (Exception e) {
message = e.toString();
}
return message;
}
public String getAction() {
System.out.println("Getting action");
return action;
}
public void setAction(String a) {
System.out.println("Setting action : " + a);
action = a;
}
public String getId() {
System.out.println("Getting id");
return id;
}
public void setId(String i) {
System.out.println("Setting id : " + i);
id = i;
}
public String getFirstName() {
System.out.println("Getting firstName");
return firstName;
}
public void setFirstName(String f) {
System.out.println("Setting first name : " + f);
firstName = f;
}
public String getLastName() {
System.out.println("Getting lastName");
return lastName;
}
public void setLastName(String l) {
System.out.println("Setting last name : " + l);
lastName = l;
}
public double getBalance() {
System.out.println("Getting balance");
return balance;
}
public void setBalance(double b) {
System.out.println("Setting balance : " + b);
balance = b;
}
public double getAmount() {
System.out.println("Getting amount");
return amount;
}
public void setAmount(double a) {
System.out.println("Setting amount : " + a);
amount = a;
}
private void reset() {
System.out.println("Calling reset()");
final String emptyString = "";
final double zero = 0.0;
setAction(emptyString);
setId(emptyString);
setFirstName(emptyString);
setLastName(emptyString);
setBalance(zero);
setAmount(zero);
}
private void loadFromEJB() {
System.out.println("Calling loadFromEJB()");
try {
setFirstName(account.getFirstName());
setLastName(account.getLastName());
setBalance(account.getBalance());
} catch (Exception re) {
System.err.println ("Failed to load AccountBean from AccountEJB.");
re.printStackTrace();v }
}
public String toString() {
StringBuffer output = new StringBuffer();
output.append("Action : " + action);
output.append( " Id : " + id);
output.append( " first name : " + firstName);
output.append( " last name : " + lastName);
output.append( " balance : " + balance);
output.append( " amount : " + amount);
return output.toString();
}
}
import javax.sql.*;
import java.util.*;
import javax.ejb.*;
import javax.naming.*;
public class AccountEJB implements EntityBean {
private String id;
private String firstName;
private String lastName;
private double balance;
private EntityContext context;
private Connection con;
private String dbName = "java:comp/env/jdbc/AccountDB";
public void debit(double amount)
throws InsufficientBalanceException {
if (balance - amount < 0) {
throw new InsufficientBalanceException();
}
balance -= amount;
}
public void credit(double amount) {
balance += amount;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
public double getBalance() {
return balance;
}
public String ejbCreate(String id, String firstName, String lastName, double balance)
throws CreateException {
if (balance < 0.00) {
throw new CreateException
("A negative initial balance is not allowed.");
}
try {
insertRow(id, firstName, lastName, balance);
} catch (Exception ex) {
throw new EJBException("ejbCreate: " + ex.getMessage());
}
this.id = id;
this.firstName = firstName;
this.lastName = lastName;
this.balance = balance;
return id;
}
public String ejbFindByPrimaryKey(String primaryKey)
throws FinderException {
boolean result;
try {
result = selectByPrimaryKey(primaryKey);
} catch (Exception ex) {
throw new EJBException("ejbFindByPrimaryKey: " + ex.getMessage());
}
if (result) {
return primaryKey;
}
else {
throw new ObjectNotFoundException
("Row for id " + primaryKey + " not found.");
}
}
public Collection ejbFindByLastName(String lastName) throws FinderException {
Collection result;
try {
result = selectByLastName(lastName);
} catch (Exception ex) {
throw new EJBException("ejbFindByLastName " + ex.getMessage());
}
if (result.isEmpty()) {
throw new ObjectNotFoundException("No rows found.");
}
else {
return result;
}
}
public Collection ejbFindInRange(double low, double high)
throws FinderException {
Collection result;
try {
result = selectInRange(low, high);
} catch (Exception ex) {
throw new EJBException("ejbFindInRange: " + ex.getMessage());
}
if (result.isEmpty()) {
throw new ObjectNotFoundException("No rows found.");
}
else {
return result;
}
}
public void ejbRemove() {
try {
deleteRow(id);
} catch (Exception ex) {
throw new EJBException("ejbRemove: " + ex.getMessage());
}
}
public void setEntityContext(EntityContext context) {
this.context = context;
try {
makeConnection();
} catch (Exception ex) {
throw new EJBException("Unable to connect to database. " +
ex.getMessage());
}
}
public void unsetEntityContext() {
try {
con.close();
} catch (SQLException ex) {
throw new EJBException("unsetEntityContext: " + ex.getMessage());
}
}
public void ejbActivate() {
id = (String)context.getPrimaryKey();
}
public void ejbPassivate() {
id = null;
}
public void ejbLoad() {
try {
loadRow();
} catch (Exception ex) {
throw new EJBException("ejbLoad: " + ex.getMessage());
}
}
public void ejbStore() {
try {
storeRow();
} catch (Exception ex) {
throw new EJBException("ejbLoad: " +
ex.getMessage());
}
}
public void ejbPostCreate(String id, String firstName,
String lastName, double balance)
{ }
/*********************** Database Routines *************************/
private void makeConnection() throws NamingException, SQLException {
InitialContext ic = new InitialContext();
DataSource ds = (DataSource) ic.lookup(dbName);
con = ds.getConnection();
}
private void insertRow (String id, String firstName, String lastName,
double balance) throws SQLException {
String insertStatement = "insert into account values ( ? , ? , ? , ? )";
PreparedStatement prepStmt =
con.prepareStatement(insertStatement);
prepStmt.setString(1, id);
prepStmt.setString(2, firstName);
prepStmt.setString(3, lastName);
prepStmt.setDouble(4, balance);
prepStmt.executeUpdate();
prepStmt.close();
}
private void deleteRow(String id) throws SQLException {
String deleteStatement = "delete from account where id = ? ";
PreparedStatement prepStmt = con.prepareStatement(deleteStatement);
prepStmt.setString(1, id);
prepStmt.executeUpdate();
prepStmt.close();
}
private boolean selectByPrimaryKey(String primaryKey)
throws SQLException {
String selectStatement =
"select id " +
"from account where id = ? ";
PreparedStatement prepStmt =
con.prepareStatement(selectStatement);
prepStmt.setString(1, primaryKey);
ResultSet rs = prepStmt.executeQuery();
boolean result = rs.next();
prepStmt.close();
return result;
}
private Collection selectByLastName(String lastName)
throws SQLException {
String selectStatement =
"select id " +
"from account where lastname = ? ";
PreparedStatement prepStmt =
con.prepareStatement(selectStatement);
prepStmt.setString(1, lastName);
ResultSet rs = prepStmt.executeQuery();
ArrayList a = new ArrayList();
while (rs.next()) {
String id = rs.getString(1);
a.add(id);
}
prepStmt.close();
return a;
}
private Collection selectInRange(double low, double high)
throws SQLException {
String selectStatement =
"select id from account " +
"where balance between ? and ?";
PreparedStatement prepStmt =
con.prepareStatement(selectStatement);
prepStmt.setDouble(1, low);
prepStmt.setDouble(2, high);
ResultSet rs = prepStmt.executeQuery();
ArrayList a = new ArrayList();
while (rs.next()) {
String id = rs.getString(1);
a.add(id);
}
prepStmt.close();
return a;
}
private void loadRow() throws SQLException {
String selectStatement =
"select firstname, lastname, balance " +
"from account where id = ? ";
PreparedStatement prepStmt =
con.prepareStatement(selectStatement);
prepStmt.setString(1, this.id);
ResultSet rs = prepStmt.executeQuery();
if (rs.next()) {
this.firstName = rs.getString(1);
this.lastName = rs.getString(2);
this.balance = rs.getDouble(3);
prepStmt.close();
}
else {
prepStmt.close();
throw new NoSuchEntityException("Row for id " + id +
" not found in database.");
}
}
private void storeRow() throws SQLException {
String updateStatement =
"update account set firstname = ? ," +
"lastname = ? , balance = ? " +
"where id = ?";
PreparedStatement prepStmt =
con.prepareStatement(updateStatement);
prepStmt.setString(1, firstName);
prepStmt.setString(2, lastName);
prepStmt.setDouble(3, balance);
prepStmt.setString(4, id);
int rowCount = prepStmt.executeUpdate();
prepStmt.close();
if (rowCount == 0) {
throw new EJBException("Storing row for id " + id + " failed.");
}
}
} // AccountEJB
doc/guides/ejb/examples/jsptobean directory.
doc/guides/ejb/examples/account directory.
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