UnknownFormatConversionException is caused by symbol '%' in String.format()

问题

String template = "%s and '%'";
String result = String.format(template, "my string");
System.out.println(result);

Expected:

my string and '%'

But result is:

java.util.UnknownFormatConversionException: Conversion = '''

Why? How to correctly declared the sequence '%' so that it's ignored by String.format()?

回答1:

% is already used by format specifiers so it requires an additional % to display that character:

String template = "%s and '%%'";

来源：https://stackoverflow.com/questions/16713396/unknownformatconversionexception-is-caused-by-symbol-in-string-format