@Service( "userService")
public class UserService extends BaseService {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Autowired
    private ScoreService scoreService;
   
    public void logon(String userName) {
        updateLastLogonTime(userName);       
        scoreService.addScore(userName, 20);
    }

    public void updateLastLogonTime(String userName) {
        String sql = "UPDATE t_user u SET u.last_logon_time = ? WHERE user_name =?";
        jdbcTemplate.update(sql, System. currentTimeMillis(), userName);
    }

    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("com/baobaotao/nestcall/applicatonContext.xml" );
        UserService service = (UserService) ctx.getBean("userService" );
        service.logon( "tom");

    }
}

@Service( "scoreUserService" )
public class ScoreService extends BaseService{
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void addScore(String userName, int toAdd) {
        String sql = "UPDATE t_user u SET u.score = u.score + ? WHERE user_name =?";
        jdbcTemplate.update(sql, toAdd, userName);
    }
}

@Service( "userService")
public class UserService extends BaseService {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Autowired
    private ScoreService scoreService;

    public void logon(String userName) {
        updateLastLogonTime(userName);
        Thread myThread = new MyThread(this.scoreService , userName, 20);//使用一个新线程运行
        myThread .start();
    }

    public void updateLastLogonTime(String userName) {
        String sql = "UPDATE t_user u SET u.last_logon_time = ? WHERE user_name =?";
        jdbcTemplate.update(sql, System. currentTimeMillis(), userName);
    }

    private class MyThread extends Thread {
        private ScoreService scoreService;
        private String userName;
        private int toAdd;
        private MyThread(ScoreService scoreService, String userName, int toAdd) {
            this. scoreService = scoreService;
            this. userName = userName;
            this. toAdd = toAdd;
        }

        public void run() {
            scoreService.addScore( userName, toAdd);
        }
    }

    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("com/baobaotao/multithread/applicatonContext.xml" );
        UserService service = (UserService) ctx.getBean("userService" );
        service.logon( "tom");
       }
}

@Service( "jdbcUserService" )
public class JdbcUserService {
    @Autowired
    private JdbcTemplate jdbcTemplate;
   
    @Transactional
    public void logon(String userName) {
        try {
            Connection conn = jdbcTemplate.getDataSource().getConnection();           
            String sql = "UPDATE t_user SET last_logon_time=? WHERE user_name =?";
            jdbcTemplate.update(sql, System. currentTimeMillis(), userName);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    public static void asynchrLogon(JdbcUserService userService, String userName) {
        UserServiceRunner runner = new UserServiceRunner(userService, userName);
        runner.start();
    }

    public static void reportConn(BasicDataSource basicDataSource) {
        System. out.println( "连接数[active:idle]-[" +
                       basicDataSource.getNumActive()+":" +basicDataSource.getNumIdle()+ "]");
    }

    private static class UserServiceRunner extends Thread {
        private JdbcUserService userService;
        private String userName;

        public UserServiceRunner(JdbcUserService userService, String userName) {
            this. userService = userService;
            this. userName = userName;
        }

        public void run() {
            userService.logon( userName);
        }
    }

    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("com/baobaotao/connleak/applicatonContext.xml" );
        JdbcUserService userService = (JdbcUserService) ctx.getBean("jdbcUserService" );
        JdbcUserService. asynchrLogon(userService, "tom");
    }
}

• Spring中DAO和Service都是以单实例的bean形式存在，Spring通过ThreadLocal类将有状态的变量（例如数据库连接Connection）本地线程化，从而做到多线程状况下的安全。在一次请求响应的处理线程中， 该线程贯通展示、服务、数据持久化三层，通过ThreadLocal使得所有关联的对象引用到的都是同一个变量。 
• 在事务属性为REQUIRED时，在相同线程中进行相互嵌套调用的事务方法工作于相同的事务中。如果互相嵌套调用的事务方法工作在不同线程中，则不同线程下的事务方法工作在独立的事务中。
• 程序只要使用SpringDAO模板，例如JdbcTemplate进行数据访问，一定没有数据库连接泄露问题！如果程序中显式的获取了数据连接Connection，则需要手工关闭它，否则就会泄露！
• 当Spring事务方法运行时，就产生一个事务上下文，它在本事务执行线程中对同一个数据源绑定了一个唯一的数据连接，所有被该事务上下文传播的方法都共享这个连接。要获取这个连接，如要使用Spirng的资源获取工具类DataSourceUtils。
• 事务管理上下文就好比一个盒子，所有的事务都放在里面。如果在某个事务方法中开启一个新线程，新线程中执行另一个事务方法，则由上面第二条可知这两个方法运行于两个独立的事务中，但是：如果使用DataSourcesUtils，则新线程中的方法可以从事务上下文中获取原线程中的数据连接！

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