how to check user input a string or number using switch statement in java?

Question

I'm working on scanner code. How can I check the file contains number or strings by using switch statement? Here is my switch statement part code

while(st.hasMoreTokens()){
    int caret=jTextArea1.getCaretPosition();
    switch(st.nextToken()){  
    case "++": jTextArea1.insert("++"+" "+":Unary Operator "+"\n",caret);
               break;
    case "--": jTextArea1.insert("--"+" "+":Unary Operator "+"\n",caret);
               break;
    }
}

Possible duplicate of [What's the best way to check to see if a String represents an integer in Java?](http://stackoverflow.com/questions/237159/whats-the-best-way-to-check-to-see-if-a-string-represents-an-integer-in-java) — Aaron, Oct 23 '15 at 09:37

score 0 · Answer 1 · answered Oct 23 '15 at 09:34

0

Write a method which will return true if the input param is a number other wise it will throw NFE and as a result it will return false :

public static boolean isInteger(String s) {
    try { 
        Integer.parseInt(s); 
    } catch(NumberFormatException e) { 
        return false; 
    } 
    return true;
}

answered Oct 23 '15 at 09:34

Rahman

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I want if any string found in file then set textarea jTextArea1.insert("here string "+" "+":String "+"\n",caret); – Asher Khan Oct 23 '15 at 09:38
I want to check this contains string or number st.hasMoreTokens() – Asher Khan Oct 23 '15 at 09:40
Not getting you. If you want to check `st.nextToken()` contains number or string, pass `st.nextToken()` to `isInteger()` method – Rahman Oct 23 '15 at 09:55

how to check user input a string or number using switch statement in java?

1 Answers1