java - 如何使用 Formatter 在 Java 中格式化字符串

Question

public class Test {
    public static void main(String[] args) {
        final String test1 = new String("01,");
        final String test2 = new String("01,0");
        final String test3 = new String("1,00");

        String pattern = "##,##";
        DecimalFormat formatter;
        DecimalFormatSymbols dfs = new DecimalFormatSymbols();
        dfs.setGroupingSeparator(',');

        formatter = new DecimalFormat(pattern, dfs);
        String result1 = formatter.format(test1);
        String result2 = formatter.format(test2);
        String result3 = formatter.format(test3);

        System.out.println("Result 1 == " + result1);
        System.out.println("Result 2 == " + result2);
        System.out.println("Result 3 == " + result3);
    }
}

我正在尝试格式化字符串。我添加了用于格式化的代码。我越来越异常(exception)。

我希望所有这些的结果都是 01,00。

异常 -

Exception in thread "main" java.lang.IllegalArgumentException: Cannot format given Object as a Number
    at java.text.DecimalFormat.format(DecimalFormat.java:487)
    at java.text.Format.format(Format.java:140)
    at com.test.Test.main(Test.java:21)

如果有人有任何想法，请指导我。

Answer 1

DecimalFormat.format 只接受 Date 或 Number 对象，不接受 String!

EDIT-1:

1) 字符串模式 = "00.00"

2)

        String result1 = formatter.format(formatter.parse(test1));
        String result2 = formatter.format(formatter.parse(test2));
        String result3 = formatter.format(formatter.parse(test3));

例如:对于

    final String test1 = new String("01,");
    final String test2 = new String("02,3");
    final String test3 = new String("1,00");

它给了我:

Result 1 == 01,00
Result 2 == 02,30
Result 3 == 01,00