persistence注意事项

1. Don't simply return data which was put into cache, make a shallow copy of that.

 List value = 
 cache.put(key, value);
3 return new ArrayList(value);

2.Do not construct query string directly. Use something like:

 String sqlString = "insert into application_authorization(application_id, security_token)"
                 + " values(:applicationId, :securityToken)";
 Query query = session.createSQLQuery(sqlString);
 query.setLong("applicationId", applicationId);
 query.setString("securityToken", hashSecurityToken);

3. To get entity by id, simply use session.get(clazz, id);

4. Code rafactoring！extract the frequently used code to util or helper class！

5. 数据库操作的component单元测试中，要在tearDown中做清理数据库的操作。