Kỹ thuật Autowiring sử dụng annotation trong Spring Framework

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

<modelVersion>4.0.0</modelVersion>
<groupId>vn.smartjob.demo</groupId>
<artifactId>demoSpring</artifactId>
<packaging>war</packaging>
<version>1.0.0-SNAPSHOT</version>
<name>demoSpring Maven Webapp</name>
<url>http://smartJob.vn</url>

<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
</dependencies>
<build>
<finalName>demoSpring</finalName>
</build>
</project>

package vn.smartJob.demoSpring.annotationBasedAutowiring;

import java.util.Date;

/**
* Account domain.
* 
* @author SmartJob
*/
public class Account {

private long id;
private String ownerName;
private double balance;
private Date accessTime;
private boolean locked;

public Account() {

}

public Account(long id, String ownerName, double balance, Date accessTime, boolean locked) {
this.id = id;
this.ownerName = ownerName;
this.balance = balance;
this.accessTime = accessTime;
this.locked = locked;
}

public long getId() {
return id;
}

public void setId(long id) {
this.id = id;
}

public String getOwnerName() {
return ownerName;
}

public void setOwnerName(String ownerName) {
this.ownerName = ownerName;
}

public double getBalance() {
return balance;
}

public void setBalance(double balance) {
this.balance = balance;
}

public Date getAccessTime() {
return accessTime;
}

public void setAccessTime(Date accessTime) {
this.accessTime = accessTime;
}

public boolean isLocked() {
return locked;
}

public void setLocked(boolean locked) {
this.locked = locked;
}

}

package vn.smartJob.demoSpring.annotationBasedAutowiring;

import java.util.List;

/**
* Interface dùng để làm khuôn cho các phương thức (method) truy vấn dữ liệu.
* 
* @author SmartJob
*/
public interface AccountDAO {

public void insert(Account account);

public void update(Account account);

public void update(List<Account> accounts);

public void delete(long accountId);

public Account find(long accountId);

public List<Account> find(List<Long> accountIds);

public List<Account> find(String ownerName);

public List<Account> find(boolean locked);

}

package vn.smartJob.demoSpring.annotationBasedAutowiring;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Repository;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Repository
@Qualifier("accountDao")
public class AccountDAOInMemoryImpl implements AccountDAO {

private Map<Long, Account> accountsMap = new HashMap<>();

{
Account account1 = new Account();
account1.setId(1L);
account1.setOwnerName("Hoang The Anh");
account1.setBalance(8000000.0);

Account account2 = new Account();
account2.setId(2L);
account2.setOwnerName("Nguyen Duc Hai");
account2.setBalance(4000000.0);

accountsMap.put(account1.getId(), account1);
accountsMap.put(account2.getId(), account2);
}

@Override
public void insert(Account account) {
accountsMap.put(account.getId(), account);
}

@Override
public void update(Account account) {
accountsMap.put(account.getId(), account);
}

@Override
public void update(List<Account> accounts) {
for (Account account : accounts) {
update(account);
}
}

@Override
public void delete(long accountId) {
accountsMap.remove(accountId);
}

@Override
public Account find(long accountId) {
return accountsMap.get(accountId);
}

@Override
public List<Account> find(List<Long> accountIds) {
List<Account> accounts = new ArrayList<>();
for (Long id : accountIds) {
accounts.add(accountsMap.get(id));
}
return accounts;
}

@Override
public List<Account> find(String ownerName) {
List<Account> accounts = new ArrayList<>();
for (Account account : accountsMap.values()) {
if (ownerName.equals(account.getOwnerName())) {
accounts.add(account);
}
}
return accounts;
}

@Override
public List<Account> find(boolean locked) {
List<Account> accounts = new ArrayList<>();
for (Account account : accountsMap.values()) {
if (locked == account.isLocked()) {
accounts.add(account);
}
}
return accounts;
}

}

package vn.smartJob.demoSpring.annotationBasedAutowiring;

/**
* Interface service.
* 
* @author SmartJob
*/
public interface AccountService {

public void transferMoney(long sourceAccountId, long targetAccountId, double amount);

public void depositMoney(long accountId, double amount) throws Exception;

public Account getAccount(long accountId);

}

package vn.smartJob.demoSpring.annotationBasedAutowiring;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;

/**
* Truy vấn dữ liệu.
*
* @author SmartJob
*/
@Service
public class AccountServiceImpl implements AccountService {
private AccountDAO accountDAO;

@Autowired
@Qualifier("accountDao")
public void setAccountDao(AccountDAO accountDAO) {
this.accountDAO = accountDAO;
}

/**
* Giao dịch Chuyển tiền.
* 
* @param sourceAccountId Tài khoản người gửi
* @param targetAccountId Tài khoản người nhận
* @param amount Số tiền chuyển khoản
*/
@Override
public void transferMoney(long sourceAccountId, long targetAccountId, double amount) {
Account sourceAccount = accountDAO.find(sourceAccountId);
Account targetAccount = accountDAO.find(targetAccountId);
sourceAccount.setBalance(sourceAccount.getBalance() - amount);
targetAccount.setBalance(targetAccount.getBalance() + amount);
accountDAO.update(sourceAccount);
accountDAO.update(targetAccount);
}

@Override
public void depositMoney(long accountId, double amount) throws Exception {
Account account = accountDAO.find(accountId);
account.setBalance(account.getBalance() + amount);
accountDAO.update(account);
}

@Override
public Account getAccount(long accountId) {
return accountDAO.find(accountId);
}

}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans 
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context 
http://www.springframework.org/schema/context/spring-context-4.0.xsd">

<context:component-scan base-package="vn.smartJob.demoSpring.annotationBasedAutowiring"/>

</beans>

package vn.smartJob.demoSpring.annotationBasedAutowiring;

import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
* Ứng dụng chuyển tiền.
*
* @author SmartJob
*/
public class App {

public static void main(String[] args) {
ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
AccountService accountService = applicationContext.getBean("accountServiceImpl", AccountService.class);

System.out.println("Trước khi chuyển tiền");
System.out.println("Số dư trong tài khoản Hoàng Thế Anh:" + accountService.getAccount(1).getBalance());
System.out.println("Số dư trong tài khoản Nguyễn Đức Hải:" + accountService.getAccount(2).getBalance());

// Hoàng Thế Anh chuyển cho Nguyễn Đức Hải 4 triệu 200 nghìn đồng.
accountService.transferMoney(1, 2, 4200000.0);

System.out.println("---------------------------------------------------");
System.out.println("Sau khi chuyển tiền");
System.out.println("Số dư trong tài khoản Hoàng Thế Anh:" + accountService.getAccount(1).getBalance());
System.out.println("Số dư trong tài khoản Nguyễn Đức Hải:" + accountService.getAccount(2).getBalance());
}

}

// Kết quả:

//Trước khi chuyển tiền
//Số dư trong tài khoản Hoàng Thế Anh:8000000.0
//Số dư trong tài khoản Nguyễn Đức Hải:4000000.0
//---------------------------------------------------
//Sau khi chuyển tiền
//Số dư trong tài khoản Hoàng Thế Anh:3800000.0
//Số dư trong tài khoản Nguyễn Đức Hải:8200000.0