Using the spring framework, when the app starts, load the data

Scenario Description:

Sometimes we need to load some infrequently-changed data into the cache when the app starts, avoid querying the database or other data sources every time the request is made, to improve performance (preparing the connection, establishing the connection, closing the connection, Reduce the number of IO data read). If the spring frame is used in the application, it is possible to implement this function with spring mechanism.

Solution:

1: Write a class, implement the Beanpostprocessor interface, this interface has two methods.

(1): Postprocessbeforeinitialization method, call this method before bean initialization defined in spring

(2): Postprocessafterinitialization method, call this method after bean initialization defined in spring

Example code:

public class Cachebeanpostprocessor implements Beanpostprocessor {


	@Override public
	Object Postprocessafterinitialization (Object obj, String arg1) throws Beansexception {
		try {
			if (obj instanceof Columnservice) {  
				((columnservice) obj). Getcolumnlist ();//Load column data
	        }else if (obj instanceof Tradeserviceimpl) { (
	        	(Tradeserviceimpl) obj). Gettradelist ();//Load Industry data
	        }
		} catch (Exception e) {
			 e.printstacktrace ();
		} 
                return obj;  
	}

	
	@Override Public
	Object Postprocessbeforeinitialization (Object arg0, String arg1)
			throws Beansexception {
		//TODO auto-generated method stub
		return arg0;
	}

}

2: In the spring XML file, add

<!--initial cache data, which is used before and after the bean defined in spring is initialized with this implementation class--
<bean id= "Cachebeanpostprocessor" class= "Com.guagua.cache.CacheBeanPostProcessor"/>

3: After loading the data, where the data exists, you will decide, I This example is placed in a "static variable"

@Service ("Columnservice") Public
class Columnserviceimpl implements Columnservice {public

	static list< column> columnlist = new arraylist<column> ();
	@Autowired
	private Columndao Columndao;

	public void Setcolumndao (Columndao columndao) {
		This.columndao = Columndao;
	}
	
	@Override public
	list<column> getcolumnlist () throws Exception {
		columnlist = columndao.getcolumnlist () ;
		return columnlist;
	}
}

Concluding remarks:

If in doubt, please make an objection.