Java Printwriter输出不接受。是否将printf格式化程序转换为文件?
使用以下代码输出到已建立的文件时:Java Printwriter输出不接受。是否将printf格式化程序转换为文件?,java,printwriter,Java,Printwriter,使用以下代码输出到已建立的文件时: import java.util.Scanner; import java.io.*; public class BarakProductOrder { public static void main(String[] args) throws IOException { //Establish scanner object Scanner input = new Scanner (System.in);
import java.util.Scanner;
import java.io.*;
public class BarakProductOrder
{
public static void main(String[] args) throws IOException
{
//Establish scanner object
Scanner input = new Scanner (System.in);
//Declare variables
String name, product, street, city, state, zip;
int qty;
double price;
//Collect data
System.out.println("Welcome to Matt's Dog Food Emporium!\n\nWhat is your name?");
name = input.nextLine();
System.out.println("Which product would you like to order today?");
product = input.nextLine();
System.out.println("How many would you like?");
qty = input.nextInt();
price = 4.56*qty;
input.nextLine(); //Must be placed to not skip over "address" line
System.out.println("Enter your street address:");
street = input.nextLine();
System.out.println("Enter the City:");
city = input.nextLine();
System.out.println("Enter the State (ex.: NY):");
state = input.nextLine();
System.out.println("Enter the Zip:");
zip = input.nextLine();
System.out.println("Thank you for your order, " + name);
//Output data to file "BarakOrder.txt"
PrintWriter outputFile = new PrintWriter("C:\\Users\\fbara\\Desktop\\CISS 110\\BarakOrder.txt");
outputFile.println("Order Number: 001");
outputFile.println("Product: " + product);
outputFile.println("Quantity: " + qty);
outputFile.printf("Price = 4.56*" + qty + " = $" + "%.2f" + price);
outputFile.println("Customer Contact Info: " + name);
outputFile.println("Address: " + street);
outputFile.println(city + ", " + state + " " + zip);
//Close scanner and file object
input.close();
outputFile.close();
System.out.println("Data has been written.");
}
}
在第45行使用“%.2f”修饰符会显示以下错误消息:
java.util.MissingFormatArgumentException:位于的格式说明符“%.2f”
位于的java.util.Formatter.format(未知源)
java.io.PrintWriter.format(未知源代码)位于
java.io.PrintWriter.printf(未知源代码)位于
main(BarakProductOrder.java:45)位于
sun.reflect.NativeMethodAccessorImpl.invoke0(本机方法)位于
位于的sun.reflect.NativeMethodAccessorImpl.invoke(未知源)
sun.reflect.DelegatingMethodAccessorImpl.invoke(未知源)位于
java.lang.reflect.Method.invoke(未知源代码)位于
edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:267)
我是否在
outputFile.printf
中使用了错误的修饰符?或错误“.print()”行?这不是printf
的工作原理;你给它一个格式,然后打印出来
您并没有将任何内容传递给%.2f
,而是尝试添加它。这些文档提供了如何使用它的信息(世界上有很多例子)
大致:
outputFile.printf("Price = 4.56*" + qty + " = $" + "%.2f", price);
虽然我不知道你为什么不为
qty
啊,可怕的逗号做同样的格式化…我想我需要多加注意。是的,解决了,谢谢。Qty是一个int,为什么我需要它呢?@FaridB你不需要它,但是因为你已经在格式化了,在我看来,不需要字符串连接就更容易阅读。