我正在使用EJB和JPA在Eclipse开发一个应用程序。
我的会话bean是：
package itso.bank.session;
import itso.bank.entities.Account;
import itso.bank.entities.Customer;
import itso.bank.entities.Transaction;
import itso.bank.exception.ITSOBankException;
import itso.bank.service.EJBBankService;
import java.math.BigDecimal;
import java.util.Arrays;
import java.util.List;
import javax.ejb.Stateless;
import javax.persistence.*;
/**
* Session Bean implementation class EJBBankBean
*/
@Stateless
public class EJBBankBean implements EJBBankService {
@PersistenceContext (unitName="RAD8JPA", type=PersistenceContextType.TRANSACTION)
private EntityManager entityMgr;
/**
* Default constructor.
*/
public EJBBankBean() {
// TODO Auto-generated constructor stub
}
public void addCustomer(Customer customer) throws ITSOBankException {
System.out.println("addCustomer: " + customer.getSsn());
entityMgr.persist(customer);
}
public void closeAccount(String ssn, String id) throws ITSOBankException {
System.out.println("closeAccount: " + id + " of customer " + ssn);
Account account = getAccount(id);
Transaction[] trans = getTransactions(id);
for (Transaction tx : trans) {
entityMgr.remove(tx);
}
entityMgr.remove(account);
System.out.println("closed account with " + trans.length + " transactions");
}
public void deleteCustomer(String ssn) throws ITSOBankException {
System.out.println("deleteCustomer: " + ssn);
Customer customer = getCustomer(ssn);
Account[] accounts = getAccounts(ssn);
for (Account acct : accounts) {
closeAccount(ssn, acct.getId());
}
entityMgr.remove(customer);
}
public void deposit(String id, BigDecimal amount) throws ITSOBankException {
System.out.println("deposit: " + id + " amount " + amount);
Account account = getAccount(id);
try {
Transaction tx = account.processTransaction(amount, Transaction.CREDIT);
entityMgr.persist(tx);
} catch (Exception e) {
throw new ITSOBankException(e.getMessage());
}
}
public Account getAccount(String id) throws ITSOBankException {
System.out.println("getAccount: " + id);
try {
return entityMgr.find(Account.class, id);
} catch (Exception e) {
System.out.println("Exception: " + e.getMessage());
throw new ITSOBankException(id);
}
}
public Account[] getAccounts(String ssn) throws ITSOBankException {
System.out.println("getAccounts: " + ssn);
Query query = null;
try {
query = entityMgr.createNamedQuery("getAccountsBySSN");
query.setParameter(1, ssn);
List<Account> accountList = query.getResultList();
Account[] array = new Account[accountList.size()];
return accountList.toArray(array);
} catch (Exception e) {
System.out.println("Exception: " + e.getMessage());
throw new ITSOBankException(ssn);
}
}
public Customer getCustomer(String ssn) throws ITSOBankException {
System.out.println("getCustomer: " + ssn);
//Query query = null;
try {
//query = entityMgr.createNamedQuery("getCustomerBySSN");
//query.setParameter(1, ssn);
//return (Customer)query.getSingleResult();
return entityMgr.find(Customer.class, ssn);
} catch (Exception e) {
System.out.println("Exception: " + e.getMessage());
throw new ITSOBankException(ssn);
}
}
public Customer[] getCustomers(String partialName) throws ITSOBankException {
System.out.println("getCustomer: " + partialName);
Query query = null;
try {
query = entityMgr.createNamedQuery("getCustomersByPartialName");
query.setParameter(1, partialName);
List<Customer> beanlist = query.getResultList();
Customer[] array = new Customer[beanlist.size()];
return beanlist.toArray(array);
} catch (Exception e) {
throw new ITSOBankException(partialName);
}
}
public Customer[] getCustomersAll() {
System.out.println("getCustomers: all");
Query query = null;
try {
query = entityMgr.createNamedQuery("getCustomers");
List<Customer> beanlist = query.getResultList();
Customer[] array = new Customer[beanlist.size()];
return beanlist.toArray(array);
} catch (Exception e) {
System.out.println("Exception: " + e.getMessage());
return null;
}
}
public Transaction[] getTransactions(String accountID) throws ITSOBankException {
System.out.println("getTransactions: " + accountID);
Query query = null;
try {
query = entityMgr.createNamedQuery("getTransactionsByID");
query.setParameter(1, accountID);
List<Transaction> transactionsList = query.getResultList();
Transaction[] array = new Transaction[transactionsList.size()];
return transactionsList.toArray(array);
} catch (Exception e) {
System.out.println("Exception: " + e.getMessage());
e.printStackTrace();
throw new ITSOBankException(accountID);
}
}
public String openAccount(String ssn) throws ITSOBankException {
System.out.println("openAccount: " + ssn);
Customer customer = getCustomer(ssn);
int acctNumber = (new java.util.Random()).nextInt(899999) + 100000;
String id = "00" + ssn.substring(0, 1) + "-" + acctNumber;
Account account = new Account();
account.setId(id);
entityMgr.persist(account);
List<Customer> custSet = Arrays.asList(customer);
account.setCustomers(custSet);
System.out.println("openAccount: " + id);
return id;
}
public void transfer(String idDebit, String idCredit, BigDecimal amount) throws ITSOBankException {
System.out.println("transfer: " + idCredit + " " + idDebit + " amount " + amount);
withdraw(idDebit, amount);
deposit(idCredit, amount);
}
public void updateCustomer(String ssn, String title, String firstName, String lastName) throws ITSOBankException {
System.out.println("updateCustomer: " + ssn);
Customer customer = getCustomer(ssn);
customer.setTitle(title);
customer.setLastName(lastName);
customer.setFirstName(firstName);
System.out.println("updateCustomer: " + customer.getTitle() + " " + customer.getFirstName() + " " + customer.getLastName());
}
public void withdraw(String id, BigDecimal amount) throws ITSOBankException {
System.out.println("withdraw: " + id + " amount " + amount);
Account account = getAccount(id);
try {
Transaction tx = account.processTransaction(amount, Transaction.DEBIT);
entityMgr.persist(tx);
} catch (Exception e) {
throw new ITSOBankException(e.getMessage());
}
}
}
我的JPA已经连接到EJB项目。我的问题是我如何从Java服务器页面调用Session Bean，而无需Servlet？
谢谢！
简单地说，通过@Named注释
@Stateless
@Named("eJBBankBean")
public class EJBBankBean implements EJBBankService {....}
在您的JSP文件中，使用： #{ejbBankBean.yourServiceMethod(parameter1_ifAny,parameter2_ifAny)}
@Named是CDI注释，没有@Named EJB bean在JSP EL中将看不见'$'或Unified El I.
我想必须有一个不使用MVC框架的原因。
所以，假设您正在使用本地接口，这是我记得从.jsp
调用EJB的最干净，标准的方式<ejb-local-ref>
<ejb-ref-name>MyBeanName</ejb-ref-name>
<ejb-ref-type>Session</ejb-ref-type>
<local>com.myapp.ejb.MyBeanLocal</local>
</ejb-local-ref>
然后从您的JSP
<%
String lookupUrl = "java:comp/env/MyBeanName";
Context ctx = new javax.naming.InitialContext();
MyBeanNameLocal ejbLocal = (MyBeanNameLocal) ctx.lookup(lookupUrl);
String output = ejbLocal.myBusinessMethod();
%>