alternative solutions for Static Methods And Singleton in java database

i Want to make a class and some methods in that class which interact with database. Many other classes Should call that methods.

Q1:is it possible to create only one instance of that class for others ?

Q2:Can i give methods as Static?

Q3:Is there is any alternative solution for stati开发者_如何转开发c and singleton for java database?

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I have not used singletons in Java yet. However, there's a pretty good discussion on the subject at http://c2.com/cgi/wiki?JavaSingleton

Basically, you will make your constructor private along with a private static final instance variable. Then you will need a public static getInstance method that returns your instance. It gets a bit more complicated if you need to be thread safe, so read the linked article.

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You can also use an enum with a single variable INSTANCE like below:

public enum EmployeeDAO {
INSTANCE;

static{
    //Initialize connection info etc.
    init();
}

private EmployeeDAO(){
    //Constructor stuff
}

public Employee getEmployeesById(int id){
            //Replace this with your data retrieval logic
    return null;
}

public Employee getDeadBeatEmployees(){
            //Replace this with your data retrieval logic
    return null;
}

public Employee getAllStars(){
            //Replace this with your data retrieval logic
    return null;
}

public static void init(){

}

}

public class Employee{}

public class SillyCanuck{
    public static void main(String args[]){

    EmployeeDAO.INSTANCE.getEmployeeById(5);
}

}