能不能帮我分析下 下面这个题目啊
/** (3)
* 将money格式化成逗点加小数点形式
* 如：formatMoney("123456")将返回"123,456.00"
* formatMoney("1234567.10")将返回"1,234,567.10"
* 当输入为不合法的数字时抛出异常
*/
public String formatMoney(String money) throw Exception;
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public String formatMoney(String money) throw Exception
{
try{
Interger.pase(money);
}catch(Exception e)
{
throw IlleageArguException();
}
DicimalFormater formater = new Dicimalformater("###,###,###.00");
return formater.format(money);
}
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package test;
import java.text.DecimalFormat;
public class Testtt {
public String formatMoney(String money) throws Exception {
Double num;
try {
num =Double.parseDouble(money);
} catch (Exception e) {
throw new IllegalArgumentException("please input a number");
}
DecimalFormat formater = new DecimalFormat("###,###.00");
return formater.format(num);
}
public static void main(String[] args) {
Testtt tt = new Testtt();
try {
System.out.println(tt.formatMoney("123456"));
System.out.println(tt.formatMoney("1234567.10"));
} catch (Exception e) {
e.printStackTrace();
}
}
}
------解决方案--------------------
DecimalFormat
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- Java code
public static void formatMoney(String money) { if (!money.matches("(?!(\\.|[0]{2,}))[\\d\\.]*(?<!\\.)")){ System.out.println("Invalid Number"); return; } int integralNumber = money.indexOf('.'); int newCharLength = (integralNumber - 1) / 3 + money.length(); char[] c = new char[newCharLength]; for (int i = integralNumber % 3; i < integralNumber; i += 3) { if (i != 0) { c[i++] = ','; } } int count = 0; for (int i = 0; i < newCharLength; i++) { if (c[i] != ',') { c[i] = money.charAt(count++); } } System.out.println("The answer is: "); System.out.println(c); }
------解决方案--------------------
- Java code
public class Test { public static void main(String[] args) { String str = "1234567"; System.out.println(formatMoney(str)); str = "1234567.10"; System.out.println(formatMoney(str)); } public static String formatMoney(String money) { if(!money.matches("\\d+(\\.\\d{1,2})?")) { throw new IllegalArgumentException("money format error!"); } int pointIndex = money.indexOf("."); if(pointIndex < 0) { money = money + ".00"; } if(pointIndex == money.length() - 2) { money = money + "0"; } money = money.replaceAll("(?<=\\d)(?=(?:\\d\\d\\d)+\\.)", ","); return money; }}
------解决方案--------------------
使用DecimalFormat或者，你有时间，也可以试试NumberFormat
同意2楼的做法。
------解决方案--------------------
money = money.replaceAll("(?<=\\d)(?=(?:\\d\\d\\d)+\\.)", ",");