how to compare the values present in excel table and value taken by the user in java programming

I have used if loop to compare the values present in table and the value entered from the user, but in the code its not entering to if loop rather it is entering to else loop, i need the suggestion for the problem.

Here is the code :

public void idExists(String SkillID) {

    try{
        Connection conn = dbconnect();
        开发者_StackOverflow中文版conn.setReadOnly(false);
        Statement st = conn.createStatement();
        String  skilid= "Select [Skill ID]from [Skill Master$]";
        ResultSet rs = st.executeQuery(skilid);

        while(rs.next()){

              String Skill = rs.getString("Skill ID");
                          System.out.println(SkillID);
        }
            if (SkillID==Skill) {
                System.out.println("the skill id  exist");   
                } 
            else { 
                System.out.println("the skill id doesnt exist");    
                    }   

            endConnect();


    }
    catch(SQLException e) {
        System.err.println("Got an exception in idexist");
        System.err.println(e.getMessage());

        }
    } 

}

You're comparing string value by reference.
Since your variable refer to two different String instances with the same value, the condition is false.

You should compare strings using the equals method.

Also, you probably want to put the if inside the loop.

Finally, you should replace all of that code with a (parameterized!) WHERE clause.