Chapter 10: JPA Integration"
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= Overview = | = Overview = | ||
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In previous chapters, we mimic a database with a static list as follows: | In previous chapters, we mimic a database with a static list as follows: | ||
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| + | ''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. We will create a simple database with HSQL and implement a persistence layer in DAO (Data Access Object) pattern to encapsulate all database related operations. | ||
= Configuration= | = Configuration= | ||
Revision as of 06:29, 5 February 2013
Overview
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;
}
...
}
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. We will create a simple database with HSQL and implement a persistence layer in DAO (Data Access Object) pattern to encapsulate all database related operations.