Chapter 10: JPA Integration

Overview

Java Persistence API (JPA) is a POJO-based persistence specification. It offers object-relational mapping solution to enterprise Java applications. In this chapter, we don't create new applications, but re-write data persistence part of previous examples with JPA.

In previous chapters, we mimic a database with a static list as follows:

public class UserInfoServiceImpl implements UserInfoService,Serializable{

	
	static protected List<User> userList = new ArrayList<User>();  
	static{
		userList.add(new User("anonymous","1234","Anonymous","[email protected]"));
		userList.add(new User("admin","1234","Admin","[email protected]"));
		userList.add(new User("zkoss","1234","ZKOSS","[email protected]"));
	}
	
	/** synchronized is just because we use static userList in this demo to prevent concurrent access **/
	public synchronized User findUser(String account){
		int s = userList.size();
		for(int i=0;i<s;i++){
			User u = userList.get(i);
			if(account.equals(u.getAccount())){
				return User.clone(u);
			}
		}
		return null;
	}
	
...
}