正在java中格式化I/O文件中的双值。。。

请问我如何将此程序中更新的薪资值设置为小数点后2位

     package elapsedTime;
import java.io.*;
import java.util.*;
public class Salary {

public static void main(String[] args)throws FileNotFoundException {
    String firstname,lastname;
    double currentSalary, PayIncrease;
    double updatedsalary;
Scanner infile=new Scanner(new FileReader("Ch3_Ex7Data.txt"));
PrintWriter Outfile=new PrintWriter("Outdata.dat");
    firstname=infile.next();
    lastname=infile.next();
    currentSalary=infile.nextDouble();
    PayIncrease=infile.nextDouble();
    updatedsalary=((PayIncrease*currentSalary)/100)+currentSalary;
Outfile.printf("FIRSTNAME:"+firstname+"\n"+"LASTNAME:"+lastname+"\n"+"UPDATEDSALARY:"+updatedsalary+"\n"+"\n");
firstname=infile.next();
lastname=infile.next();
currentSalary=infile.nextDouble();
PayIncrease=infile.nextDouble();
updatedsalary=((PayIncrease*currentSalary)/100)+currentSalary;
Outfile.printf("FIRSTNAME:"+firstname+"\n"+"LASTNAME:"+lastname+"\n"+"UPDATEDSALARY:"+updatedsalary+"\n"+"\n");
firstname=infile.next();
lastname=infile.next();
currentSalary=infile.nextDouble();
PayIncrease=infile.nextDouble();
updatedsalary=((PayIncrease*currentSalary)/100)+currentSalary;
Outfile.printf("FIRSTNAME:"+firstname+"\n"+"LASTNAME:"+lastname+"\n"+"UPDATEDSALARY:"+updatedsalary+"\n"+"\n");
infile.close();
Outfile.close();
}

}

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我主要不知道在Outfile.printf语句中在哪里使用格式说明符。

您可能正在寻找。 你会这样做

double d = 2.34568;
DecimalFormat f = new DecimalFormat("##.00");
Outfile.printf(f.format(d));

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您可以使用这行代码将工资打印到小数点后2位：

Outfile.printf("FIRSTNAME:"+firstname+"\n"+"LASTNAME:"+lastname+"\n"+"UPDATEDSALARY:%.2f\n"+"\n", updatedsalary);

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缩进代码。并且只发布相关部分。这里有一个提示：这个问题已经被回答了几十次了（在这里就这样）。使用双精度来显示/操纵货币通常不是一个好主意，但是如果你仍然想走这条路，请看DecimalFormat类。谢谢大家。。。我是新手。。发布代码有点小问题。。。下次肯定会缩进我的代码。。。顺便说一下，我使用%.2f格式说明符成功地格式化了它。。。谢谢