System.out.printf 与 System.out.format

Question

System.out.printf和System.out.format是否完全相同，或者它们在某种程度上有所不同？

Answer 1

System.out is a PrintStream , and quoting the javadoc for PrintStream.printf

An invocation of this method of the form out.printf(l, format, args) behaves in exactly the same way as the invocation out.format(l, format, args)

Answer 2

The actual implementation of both printf overloaded forms

public PrintStream printf(Locale l, String format, Object ... args) {
    return format(l, format, args);
}

and

public PrintStream printf(String format, Object ... args) {
        return format(format, args);
}

uses the format method's overloaded forms

public PrintStream format(Locale l, String format, Object ... args)

and

public PrintStream format(String format, Object ... args)

respectively.

Answer 3

没有区别。他们都表现得一样。

Answer 4

The key difference between printf and format methods is:

• printf : prints the formatted String into console much like System.out.println() but
• format : method return a formatted String, which you can store or use the way you want.

Otherwise nature of use is different according to their functionalities. An example to add leading zeros to a number:

int num = 5;
String str = String.format("%03d", num);  // 005
System.out.printf("Original number %d, leading with zero : %s", num, str);
// Original number 5, leading with zero : 005