实体类:
public class Account implements Serializable {
    private Integer id;
    private String name;
    private Float money;
    //生成set/get
}

//接口
public interface IAccountService {
    void transfer(String sourceName,String targeName,Float money);
}

//实现类
public class AccountServiceImpl implements IAccountService {
    private IAccountDao accountDao;//生成set/get

    //转账方法
    public void transfer(String sourceName, String targeName, Float money) {
        //1.根据名称查询两个账户
        Account source = accountDao.findAccountByName(sourceName);
        Account target = accountDao.findAccountByName(targeName);
		//2.修改两个账户的金额
        source.setMoney(source.getMoney()-money);//转出账户减钱
        target.setMoney(target.getMoney()+money);//转入账户加钱
		//3.更新两个账户
        accountDao.updateAccount(source);
        int i=1/0;   //抛出异常测试事务是否起作用
        accountDao.updateAccount(target);
    }
}

//接口
public interface IAccountDao {
    Account findAccountByName(String name);
    void updateAccount(Account account);
}

//实现类   继承JdbcDaoSupport的方式
public class AccountDaoImpl extends JdbcDaoSupport implements IAccountDao {
    //根据账户名称查询
    public Account findAccountByName(String name) {
        List<Account> list = getJdbcTemplate().query("select * from account where name = ? ",
                                                     new AccountRowMapper(),name);
        if(list.isEmpty()){
            return null;
        }
        if(list.size()>1){
            throw new RuntimeException("结果集不唯一，不是只有一个账户对象");
        }
        return list.get(0);
    }

    //更新账户
    public void updateAccount(Account account) {
        super.getJdbcTemplate().update("update account set money = ? where id = ? ",
                                       account.getMoney(),account.getId());
    }
}


//账户的封装类 RowMapper 的实现类
public class AccountRowMapper implements RowMapper {
    public Object mapRow(ResultSet resultSet, int i) throws SQLException {
        Account account = new Account();
        account.setId(resultSet.getInt("id"));
        account.setName(resultSet.getString("name"));
        account.setMoney(resultSet.getFloat("money"));
        return account;
    }
}

//实现类  加入相应注解
@Service("accountService")
@Transactional(readOnly = true,propagation = Propagation.SUPPORTS)
public class AccountServiceImpl implements IAccountService {

    @Autowired
    private IAccountDao accountDao;

    @Transactional(readOnly=false,propagation=Propagation.REQUIRED)
    public void transfer(String sourceName, String targeName, Float money) {
        //1.根据名称查询两个账户
        Account source = accountDao.findAccountByName(sourceName);
        Account target = accountDao.findAccountByName(targeName);
		//2.修改两个账户的金额
        source.setMoney(source.getMoney()-money);//转出账户减钱
        target.setMoney(target.getMoney()+money);//转入账户加钱
		//3.更新两个账户
        accountDao.updateAccount(source);
        int i=1/0;  //抛出异常测试事务是否起作用
        accountDao.updateAccount(target);
    }
}

细节：
该注解的属性和 xml 中的属性含义一致。该注解可以出现在接口上，类上和方法上。
出现接口上，表示该接口的所有实现类都有事务支持。
出现在类上，表示类中所有方法有事务支持
出现在方法上，表示方法有事务支持。
以上三个位置的优先级：方法>类>接口

//实现类，加入相应注解。不能使用继承JdbcDaoSupport的方式了
@Repository("accountDao")
public class AccountDaoImpl implements IAccountDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public Account findAccountByName(String name) {
        List<Account> list = jdbcTemplate.query("select * from account where name = ? ",
                                                new AccountRowMapper(),name
                                               );
        if(list.isEmpty()){
            return null;
        }
        if(list.size()>1){
            throw new RuntimeException("结果集不唯一，不是只有一个账户对象");
        }
        return list.get(0);
    }

    public void updateAccount(Account account) {
        jdbcTemplate.update("update account set money = ? where id = ? ",
                            account.getMoney(),account.getId()
                           );
    }
}

//账户的封装类 RowMapper 的实现类  AccountRowMapper也和XML方式相同
public class AccountRowMapper implements RowMapper {
    public Object mapRow(ResultSet resultSet, int i) throws SQLException {
        Account account = new Account();
        account.setId(resultSet.getInt("id"));
        account.setName(resultSet.getString("name"));
        account.setMoney(resultSet.getFloat("money"));
        return account;
    }
}

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.PropertySource;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import javax.sql.DataSource;

@PropertySource("classpath:jdbcConfig.properties")
public class JdbcConfig {
    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;

    @Bean(name = "dataSource")
    public DriverManagerDataSource createDataSource() {
        DriverManagerDataSource ds = new DriverManagerDataSource();
        ds.setDriverClassName(driver);
        ds.setUrl(url);
        ds.setUsername(username);
        ds.setPassword(password);
        return ds;
    }

    @Bean(name = "jdbcTemplate")
    public JdbcTemplate createJdbcTemplate(DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }
}

import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;

public class TransactionConfig {
    @Bean(name = "transactionManager")
    public PlatformTransactionManager createTransactionManager(DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
}

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@ComponentScan(basePackages = {"com.mg"})
@Import({JdbcConfig.class,TransactionConfig.class})
@EnableTransactionManagement //开启Spring注解事务的支持
public class SpringConfig {

}