從文本文件中掃描

Question

我想從文本文件中打印多個信息，如打印nameOfEmployee，hourlyRate，hoursWorked，taxRate，grossAmount，netAmount，但它只給我java.util.InputMismatchException，並且在控制檯中並非全部來自員工的信息僅打印姓名，小時收入，工作時間，稅收收入，我也想要合計員工的全部總額。

private static Scanner ian; 

    public static void main (String[]args) throws FileNotFoundException 
    { 
     Scan(); 
    } 

    public static void Scan() 
    { 
     try 
     { 
      ian = new Scanner(new File("payroll.dat")); 
     } 
     catch (IOException e)  
     { 
      e.printStackTrace(); 
     } 

     while(ian.hasNext()) 
     { 
      String a = ian.nextLine(); 
      int b = ian.nextInt(); 
      int c = ian.nextInt(); 
      int d = ian.nextInt(); 
      int e = ian.nextInt(); 
      int f = ian.nextInt(); 

      System.out.printf("a= ", a , "b= ", b , " c= ", c , " d= ", d , "e = ", e , "f = " ,f); 
     } 
    } 
} 

Answer 1

請參閱 http://examples.javacodegeeks.com/core-java/lang/string/java-string-format-example/

編輯的代碼... 的printf的完整簽名的printf（字符串格式，對象...參數）。第一個參數是一個描述所需輸出格式的字符串。從那裏開始，printf可以有多個任意類型的參數。在運行時，這些參數將被轉換爲字符串，並將根據格式化指令進行打印。對於整數和％s
1％d的字符串：

import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.IOException; 
import java.util.Scanner; 




public class readfile { 
    private static Scanner ian; 

    public static void main (String[]args) throws FileNotFoundException 
    { 
     Scan(); 
    } 

    public static void Scan() 
    { 
     try 
     { 
      ian = new Scanner(new File("demo.txt")); 
     } 
     catch (IOException e) 
     { 
      e.printStackTrace(); 
     } 

     while(ian.hasNext()) 
     { 

      int b = ian.nextInt(); 
      int c = ian.nextInt(); 
      int d = ian.nextInt(); 
      int e = ian.nextInt(); 
      int f = ian.nextInt(); 
      String a = ian.nextLine(); 

      System.out.printf("a : %s, b : %d, c : %d ,d : %d ,e : %d, g : %d " ,a,b,c,d,e,f); 
     } 
    } 
} 

Answer 2

嘗試的東西更換的printf一行：

System.out.printf("a= %d b= %d c= %d d= %d e = %d f = %d" ,a,b,c,d,e,f); 

的printf就拿第一個參數字符串格式，然後其他的參數裏面

http://docs.oracle.com/javase/7/docs/api/java/io/PrintStream.html#printf(java.lang.String,%20java.lang.Object...)

Answer 3

如何格式化關於從java 7風格的文件中讀取？

public static void main(String[] arg) throws Exception { 
    try(Scanner scan = new Scanner(new File("payroll.dat"))){ 
     while(scan.hasNextLine()){ 
      // extract data here 
     } 
    } 
} 

Answer 4

從文檔的Scannerhttp://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html

nextLine()：「此掃描器執行當前行，並返回跳過的輸入信息。」

您正在檢查是否有更多的輸入與hasNext()，但你打電話nextLine()這將跳過（並返回）整個下一行。然後你打電話給nextInt()，但是在你的最後一行之後，將不會有更多的整數。

你可能想是這樣的：

while(ian.hasNextLine()) 
    { 
     int b = ian.nextInt(); 
     int c = ian.nextInt(); 
     int d = ian.nextInt(); 
     int e = ian.nextInt(); 
     int f = ian.nextInt(); 
     String a = ian.nextLine(); 

     System.out.printf("a= ", a , "b= ", b , " c= ", c , " d= ", d , "e = ", e , "f = " ,f); 
    } 
} 

，但它取決於你的文件，你還沒有發佈的格式。

Answer 5

這是原創，我嘗試過，因爲我想知道如果它只是原來是錯的，我很抱歉沒有清除我的問題，而不是特別希望你能幫助傢伙。

private static final double FULL_TIME = 40.0; 

static Scanner scanner = new Scanner(System.in); 

static String nameOfEmployee; 
static double hourlyRate; 
static double hoursWorked; 
static double taxRate; 
static double grossAmount = 0; 
static double netAmount = 0; 

static double TOtalGrossAmount = 0; 
static double TotalNetAmount = 0; 

private static Scanner ian; 



public static void main (String []args) throws IOException 

    { 

     Instructions(); 

     PayrollReport(); 

     printEmployeeInfo(nameOfEmployee, hourlyRate, hoursWorked, taxRate, grossAmount, netAmount); 

    } 



public static void Instructions() 

{ 
    System.out.println("\t\t\t\t\t\tInstructions for Payroll Report Program" + 
      "\n\t\t\t\tThis program calculates a paycheck for each employee." + 
      "\n\t\t\t\tA text file containing the following information will be created." + 
      "\n\t\t\t\tname, pay rate, hours worked, and tax percentage to be deducted"); 

    System.out.println("\n\t\t\t\tThe program will create a report in columnar format showing the " + 
      "\n\t\t\t\ttemployee name, hourly rate, number of worked, tax rate," + 
      "\n\t\t\t\tgross pay, and netpay."); 

    System.out.println("\n\t\t\t\tAfter all emplyoees are processed , totals will be displayed," + 
      "\n\t\t\t\tincluding total gross amount and total net pay."); 
} 

public static void PayrollReport() 
{ 
    { 
     System.out.println("\n\t\t\t\t\t\t\t\tPayroll Report "); 
     System.out.print(""); 

     System.out.print("\n\t\t\t\tEmployee Name " + " Hourly Rate " + " Hours Worked " + " Tax Rate " + " Gross Amount " + " Net Amount"); 

     System.out.print(""); 
     System.out.println("\n\t\t\t\t--------------- " + " ----------- " + " ------------" + " --------- " + " ----------- " + " -----------");   
    }  
} 

public static void printEmployeeInfo(String nameOfEmployee , double HourlyRate , double HoursWorked , 
     double TaxRate , double GrossAmount , double NetAmount) throws IOException 
    { 

     try 
      { 

      ian = new Scanner(new File("payroll.dat")); 

      } 

     catch (IOException e)  

     { 
      e.printStackTrace(); 
     } 


    while (ian.hasNext())  
    { 
     nameOfEmployee = ian.nextLine(); 
     HourlyRate = ian.nextInt(); 
     HoursWorked = ian.nextInt(); 
     TaxRate = ian.nextInt(); 
     GrossAmount = 0; 
     NetAmount = 0; 

     TOtalGrossAmount += GrossAmount ; 
     TotalNetAmount += NetAmount; 

     System.out.printf("%s %s %s %s %s %s \n" , "\t\t\t\t" , nameOfEmployee , " " 
       , HourlyRate , " " , HoursWorked , " " , TaxRate , GrossAmount, NetAmount);  
    } 

    System.out.printf(" " , TOtalGrossAmount + " " + TotalNetAmount); 

     ian.close(); 
    } 

}