Integer.valueOf() vs. Integer.parseInt() [duplicate]

Question

This question already has an answer here:

• Difference between parseInt and valueOf in java? 12 answers

Aside from Integer.parseInt() handling the minus sign (as documented), are there any other differences between Integer.valueOf() and Integer.parseInt()?

And since neither can parse , as a decimal thousands separator (produces NumberFormatException), is there an already available Java method to do that?

Answer 1

Actually, valueOf uses parseInt internally. The difference is parseInt returns an int primitive while valueOf returns an Integer object. Consider from the Integer.class source:

public static int parseInt(String s) throws NumberFormatException {
    return parseInt(s, 10);
}

public static Integer valueOf(String s, int radix) throws NumberFormatException {
    return Integer.valueOf(parseInt(s, radix));
}

public static Integer valueOf(String s) throws NumberFormatException {
    return Integer.valueOf(parseInt(s, 10));
}

As for parsing with a comma, I'm not familiar with one. I would sanitize them.

int million = Integer.parseInt("1,000,000".replace(",", ""));

Answer 2

First Question: Difference between parseInt and valueOf in java?

Second Question:

NumberFormat format = NumberFormat.getInstance(Locale.FRANCE);
Number number = format.parse("1,234");
double d = number.doubleValue();

Third Question:

DecimalFormat df = new DecimalFormat();
DecimalFormatSymbols symbols = new DecimalFormatSymbols();
symbols.setDecimalSeparator('.');
symbols.setGroupingSeparator(',');
df.setDecimalFormatSymbols(symbols);
df.parse(p);

Answer 3

Integer.valueOf() returns an Integer object, while Integer.parseInt() returns an int primitive.

Answer 4

parseInt() parses String to int while valueOf() additionally wraps this int into Integer. That's the only difference.

If you want to have full control over parsing integers, check out NumberFormat with various locales.

Answer 5

The difference between these two methods is:

• parseXxx() returns the primitive type
• valueOf() returns a wrapper object reference of the type.