Rest Web Services API的预处理

Question

I am building a simple web service in Java using Jersey to add and delete users from a DB.

Where is the best way to do the preprocessing for this, eg if i want to establish a connection with the DB?

@Path("/user/service")
public class UserService 
{
    private Connection connect = null;
    final private String host = "localhost";
    final private String user = "qwerty";
    final private String passwd = "mysql";
    final private String database = "user_db";

    public void connectToDB() throws Exception 
    {
        Class.forName("com.mysql.jdbc.Driver");
        connect = DriverManager.getConnection("jdbc:mysql://" + host + "/"
                        + database + "?" + "user=" + user + "&password=" + passwd);
    }

    @PUT
    @Path("/create")
    public void createUser(){
        System.out.println("Inside Create User method");
    }

    @GET
    @Path("/get/{id}")
    public String getUser(@PathParam("id")String userid, @QueryParam("first")String first){
        System.out.println("GET: " + first);
    }
}

I want to call connectToDB() once at the start and not inside every request.

Thanks

Answer 1

You can create singleton class and move your connectToDB logic into that singleton class and when invoked that singleton class will make a DB connection which can be used in all subsequent calls from the API.

You can also create a connection inside a static block but that's not a clean way imo.

More on singleton