錯誤打印字符串使用％替換格式化爲％.0f

Question

我試圖在toString()中打印字符串。如果我刪除了%.0f和this.years替代品，它會打印出正常，但如果包含它，則不會打印。我不知道爲什麼。我能想到的唯一原因可能是因爲年份是int，而我的字符串格式只適用於doubles？

如何更改代碼以便我可以將%.0f替換爲this.years？

// instance members 
private double amountBorrowed; 
private double yearlyRate; 
private int years; 
public double A; 
public double n = years * 12; 

// public instance method 
public MyLoan(double amt, double rt, int yrs) { 
    this.amountBorrowed = amt; 
    this.yearlyRate = rt; 
    this.years = yrs; 
    this.n = yrs * 12; 

public String toString() { 

    String temp1 = String.format("Loan: $%.2f at %.2f for %.0f years.", this.amountBorrowed, this.yearlyRate, this.years); 
    return temp1; 

嘗試打印時我收到的錯誤是：

Exception in thread "main" java.util.IllegalFormatConversionException: f != java.lang.Integer at java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4302) at java.util.Formatter$FormatSpecifier.printFloat(Formatter.java:2806) at java.util.Formatter$FormatSpecifier.print(Formatter.java:2753) at java.util.Formatter.format(Formatter.java:2520) at java.util.Formatter.format(Formatter.java:2455) at java.lang.String.format(String.java:2940) at hw2.MyLoan.toString(MyLoan.java:61) at hw2.MyLoan.main(MyLoan.java:101)

Answer 1

使用 '％d'，而不是 '到％.0f' 爲在格式化 '詮釋'。

對於有關格式見這裏 http://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html