Best way to get data from database inside Thread Class in Spring

Question

Currently i am troubling that how to get data from database inside my thread class.

I can't make bean of my thread class because new instance is created of thread on every request.

MyThread.class

class MyThread implements Runnable{
public void run(){
 //How to get Employee data and also data from other tables.??????
}
} 

EmployeeDAO.class

@Component("employeeDAO")
public class EmployeeDAO {
@Cacheable(value = "employeeCache")
public List<Employee> getEmployees() {
 //got data from database
 return employees;
}
}

Is this good to get context and get dao bean from context and use in every my thread class?

Can you suggest or share code how to solve my above problem?

• Mike Partridge: Make EmployeeDAO available in the class that instantiates MyThread, then pass the DAO into MyThread (ideally via the constructor) before running it.
• Kamlesh Kanazariya: @MikePartridge Is there another solution rather suggested by you because i don't want to pass every dao which required in my thread to constructor ? can you imagine that above solution is bad when i have required to get data from multiple tables inside my thread
• chrylis -cautiouslyoptimistic-: Use the constructor. Otherwise, you're creating implicit dependencies that aren't clear in your object's API and are just asking for subtle environment bugs.
• Kamlesh Kanazariya: @chrylis If I have required to use multiple DAO inside my thread then Is this good to pass every DAO inside constructor?
• chrylis -cautiouslyoptimistic-: That's exactly the kind of unreliable design I mean by "implicit dependencies". If your class needs new dependencies, then the constructor should reflect them.

Answer 1

I have found one solution from this site .

Is below solution is good or not? If not good then what are disadvantage of solution

Here is what I tried and got success

@Service
public class StaticContextHolder implements ApplicationContextAware {
public static ApplicationContext CONTEXT;
public StaticContextHolder() {
}
public static Object getBean(String s) {
 return CONTEXT.getBean(s);
}
public static <T> T getBean(String s, Class<T> tClass){
 return CONTEXT.getBean(s, tClass);
}
public static <T> T getBean(Class<T> tClass){
 return CONTEXT.getBean(tClass);
}
public static Object getBean(String s, Object... objects){
 return CONTEXT.getBean(s, objects);
}
public static boolean containsBean(String s) {
 return CONTEXT.containsBean(s);
}
@Override
public void setApplicationContext(ApplicationContext arg0) throws BeansException {
 System.out.println("ApplicationContext initialized");
 CONTEXT = arg0;
} 
} 
class MyThread implements Runnable{
public void run(){
 EmployeeDAO employeeDAO = StaticContextHolder.getBean(EmployeeDAO.class);
}
} 

• Ian McLaird: This is the Singleton (anti-)pattern. For a discussion, see this question: stackoverflow.com/questions/11292109/…