java - 如何解决 IllegalFormatConversionException

Question

public class Experiments {
    public static void main(String[] args) {
        double x;
        x = (1.3/100)*950;
        System.out.printf("1.3% of 950 is %1.2f", x);
    }
}

运行程序显示:

1.3Exception in thread "main" java.util.IllegalFormatConversionException: o != java.lang.Double at java.util.Formatter$FormatSpecifier.failConversion(Unknown Source) at java.util.Formatter$FormatSpecifier.printInteger(Unknown Source) at java.util.Formatter$FormatSpecifier.print(Unknown Source) at java.util.Formatter.format(Unknown Source) at java.io.PrintStream.format(Unknown Source) at java.io.PrintStream.printf(Unknown Source) at Experiments.main(Experiments.java:6)

Answer 1

如果您想在格式字符串中使用百分号，则需要对它们进行转义:

System.out.printf("1.3%% of 950 is %1.2f", x);

现在，Java 尝试使用 %o (八进制表示法)格式化 double 值，但这仅对整数有效。