Basic REST Web Service can not register

Question

First, I am very new on creating a web service. Someone always did it for me before, but this time I need to build it on my own. Please bear with me, I still do not understand a lot.

I followed this tutorial (you can download the source code there, I followed almost everything) and changed some variable on my need, like :

//Change these parameters according to your DB
public class Constants {
    public static String dbClass = "com.mysql.jdbc.Driver";
    private static String dbName= "users";
    public static String dbUrl = "jdbc:mysql://localhost:3306/"+dbName;
    public static String dbUser = "root";
    public static String dbPwd = "";

}

I tried to run the project, but its only running the web on eclipse's default browser (run as -> run at server). All I know is the tomcat is already running on the local server .

I followed the tutorial by turning on Apache and MySql on my XAMPP and created the table. I also installed Advanced rest client on chrome browser.

I tried to do the registration by using this URL : http://localhost:3306/useraccount/register/doregister?username=admin&password=admin and GET method on Advanced rest client, and the result is 200 OK but no JSON was returned (it should be return some JSON).

When I checked my DB on phpmyadmin, the user table is still empty so the registration is failed.

This is the registration class :

public class Register {
    // HTTP Get Method
    @GET 
    // Path: http://localhost/<appln-folder-name>/register/doregister
    @Path("/doregister")  
    // Produces JSON as response
    @Produces(MediaType.APPLICATION_JSON) 
    // Query parameters are parameters: http://localhost/<appln-folder-name>/register/doregister?name=pqrs&username=abc&password=xyz
    public String doLogin(@QueryParam("name") String name, @QueryParam("username") String uname, @QueryParam("password") String pwd){
        String response = "";
        //System.out.println("Inside doLogin "+uname+"  "+pwd);
        int retCode = registerUser(name, uname, pwd);
        if(retCode == 0){
            response = Utitlity.constructJSON("register",true);
        }else if(retCode == 1){
            response = Utitlity.constructJSON("register",false, "You are already registered");
        }else if(retCode == 2){
            response = Utitlity.constructJSON("register",false, "Special Characters are not allowed in Username and Password");
        }else if(retCode == 3){
            response = Utitlity.constructJSON("register",false, "Error occured");
        }
        return response;

    }

    private int registerUser(String name, String uname, String pwd){
        System.out.println("Inside checkCredentials");
        int result = 3;
        if(Utitlity.isNotNull(uname) && Utitlity.isNotNull(pwd)){
            try {
                if(DBConnection.insertUser(name, uname, pwd)){
                    System.out.println("RegisterUSer if");
                    result = 0;
                }
            } catch(SQLException sqle){
                System.out.println("RegisterUSer catch sqle");
                //When Primary key violation occurs that means user is already registered
                if(sqle.getErrorCode() == 1062){
                    result = 1;
                } 
                //When special characters are used in name,username or password
                else if(sqle.getErrorCode() == 1064){
                    System.out.println(sqle.getErrorCode());
                    result = 2;
                }
            }
            catch (Exception e) {
                // TODO Auto-generated catch block
                System.out.println("Inside checkCredentials catch e ");
                result = 3;
            }
        }else{
            System.out.println("Inside checkCredentials else");
            result = 3;
        }

        return result;
    }

Please help me out, I did whatever I can and I am lost now.

Thanks a lot for your time.

Answer 1

I just remembered I did something with the localhost loooongggg ago, so the correct url is http://localhost:8080/useraccount/register/doregister?username=admin&password=admin .

Now I can register successfully, but I still do not understand what is this code for : public static String dbUrl = "jdbc:mysql://localhost:3306/"+dbName; (please see my question)

Please kindly explain those things for me.

Answer 2

3306: It is the port for MySQL which accepts database requests. 8080: It is the port for tomcat which listens to Http requests.

The code: public static String dbUrl = "jdbc:mysql://localhost:3306/"+dbName;

is telling the jdbc (java database connectivity) url to connect to mysql for doing insert, delete , read operations on your backend database. The DBConnection utilizes this constant to connect to the MySQL database.

Here is a JDBC guide that may be helpful to you: http://www.tutorialspoint.com/jdbc/jdbc-quick-guide.htm

Looking at your code, I would recommend: 1. Use Log4j or Logback instead of System out 2. Return status code 500 for internal erros, 400 for validation errors etc. Here is a list of status codes that you can utilize: http://www.restapitutorial.com/httpstatuscodes.html