如何避免由于代码重复而导致的重载？

Question

I am trying to insert the name,hashed password,salt and the hash type to the database. Only thing changing is the type of the parameters. I believe that it can be done more efficiently. How can I avoid using overloading? Do I need to use generics? Thank you.

InsertMethods

protected void insert(String name, String secretpassword, String salt, String type)
{
    String sql = "INSERT INTO login(username,password,salt,type) VALUES(?,?,?,?)";

    try (Connection conn = this.connect();
         PreparedStatement pstmt = conn.prepareStatement(sql)) {
        pstmt.setString(1, name);
        pstmt.setString(2, secretpassword);
        pstmt.setString(3, salt);
        pstmt.setString(4, type);
        pstmt.executeUpdate();
        System.out.println("Successful");
    } catch (SQLException e) {
        System.out.println(e.getMessage());
    }
}

protected void insert(String name, byte[] secretpassword, String salt, String type)
{
    String sql = "INSERT INTO login(username,password,salt,type) VALUES(?,?,?,?)";

    try (Connection conn = this.connect();
         PreparedStatement pstmt = conn.prepareStatement(sql)) {
        pstmt.setString(1, name);
        pstmt.setString(2, Arrays.toString(secretpassword));
        pstmt.setString(3, salt);
        pstmt.setString(4, type);
        pstmt.executeUpdate();
        System.out.println("Successful");
    } catch (SQLException e) {
        System.out.println(e.getMessage());
    }
}

Answer 1

You can call the first method from the second one like:

protected void insert(String name, byte[] secretpassword, String salt, String type)
{
    insert(name, Arrays.toString(secretpassword), salt, type);
}

Answer 2

I don't see much of an issue here, because you always end up inserting the password as a string into your login table. So, I suggest just always using the first version:

protected void insert(String name, String secretpassword, String salt,
    String type);

If you come across your password as a byte[] , just use string's constructor to generate a String :

byte[] array = ...;
String password = new String(array);

So, to be clear, I suggest possibly deleting the second method, because other than one parameter, it does precisely the same thing at the database level.

Keeping both methods means more maintenance work in your code base, because if you change one, you will have to make the same logical changes in the other.

Answer 3

Two ways come to mind:

public String getValue(String value1) {
  return value1 + "0";
}

public String getValue(String value1, int num) {
  return value1 + String.valueOf(num);
}

Option 1: extract the code in a method that both call:

public String getValue(String value1) {
  return getMyValue(value1, 0);
}

public String getValue(String value1, int num) {
  return getMyValue(value1, num);
}

public String getMyValue(String val, int num) {
  return val + String.valueOf(num);
}

or, option 2, chain the calls:

public String getValue(String value1) {
  return getValue(value1, 0);
}

public String getValue(String value1, int num) {
  return value1 + String.valueOf(num);
}

but, in your case, you should really ask yourself whether you need both methods.