[英]Issue with writing and reading from file
我處於一種情況,我想寫一些東西(用打孔和打孔方式寫員工詳細信息)並讀回文件(以顯示所有員工打孔和打孔的人的報告)。
package Test;
import java.io.*;
import java.text.*;
import java.util.*;
public class Test {
public static void main(String[] args) throws IOException {
String lastName = "";
String firstName = "";
String choice = "y";
String customerChoice = "x";
int empid = 0;
Scanner sc = new Scanner(System.in);
int currentIndex;
File file = new File("E:/output.txt");
FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();
int[] punchedArray;
punchedArray = new int[100];
// System.out.println(t);
while (!customerChoice.equalsIgnoreCase("d") && customerChoice != "invalid" && choice.equalsIgnoreCase("y")) {
customerChoice = getValidCustomerChoice(sc);
if (customerChoice.equalsIgnoreCase("a")) {
// System.out.println("In Create Customer");
System.out.print("Enter your first name: ");
firstName = sc.next();
System.out.print("Enter your last name: ");
lastName = sc.next();
System.out.println(firstName + lastName + "with employee id" + empid);
//System.out.println(firstNameArray[newEmployeeIndex] + " " + lastNameArray[newEmployeeIndex] + " your employee ID is: " + employeeIDArray[newEmployeeIndex]);
empid++;
//sc.next();
}
if (customerChoice.equalsIgnoreCase("b")) {
System.out.println("Welcome to the punch in/out screen"+"\n");
System.out.print("Enter your employee ID: ");
currentIndex = Integer.parseInt(sc.next());
if (punchedArray[currentIndex] == 0)
{
System.out.println("You are now punched in");
punchedArray[currentIndex] = 1;
}
else if (punchedArray[currentIndex] == 1)
{
System.out.println("You are now punched out");
punchedArray[currentIndex] = 0;
}
System.out.print(firstName + " "+ lastName + " "+ "your employee ID is " + currentIndex + " and your clock date and time is: " + " "+ cal.getTime() +"\n");
String content = firstName + lastName + empid + cal.getTime();
bw.write(content);
bw.newLine();
bw.close();
}
if (customerChoice.equalsIgnoreCase("c")) {
System.out.print("Welcome to the report screen." + "\n");
System.out.print("Enter your selection (I = individual report or A= all employees):" + "\n");
customerChoice = sc.next();
if (customerChoice.equalsIgnoreCase("i")) {
System.out.println("In Individual Report");
} else if (customerChoice.equalsIgnoreCase("a")) {
System.out.println("In Consoldated Report");
}
}
if(customerChoice.equalsIgnoreCase("d"))
{
//bw.close();
break;
}
}
}
public static String getValidCustomerChoice(Scanner sc) {
String customerChoice = "";
// sc.nextLine();
boolean isValid = false;
int invalidCounter = 0;
System.out.print("Enter your selection (a= Add New Employee, b = Punch in/out, c= Report, d = Exit):");
while (isValid == false && invalidCounter < 3) {
customerChoice = sc.next();
if (!customerChoice.equalsIgnoreCase("a")
&& !customerChoice.equalsIgnoreCase("b") && !customerChoice.equalsIgnoreCase("c") && !customerChoice.equalsIgnoreCase("d") && !customerChoice.equalsIgnoreCase("I") && !customerChoice.equalsIgnoreCase("A")) {
System.out.println("Invalid choice. Try again.\n");
invalidCounter++;
} else {
isValid = true;
}
sc.nextLine();
}
if (invalidCounter >= 3) {
System.out.println("Invalid three times. Program Exiting.\n");
return "invalid";
}
return customerChoice;
}
}
在第[75]行,bw.write(content)我正在寫一個名為“ output.txt”的文件(我也想給我寫文件的那些雇員加上時間戳)。 但是由於某種原因,數據並沒有進入文件,所以我確信在關閉該文件時我在某個地方犯了一個錯誤,並且我想從我編寫的同一文件中讀取數據。 有人可以建議我哪里出問題了嗎?
添加更多詳細信息:
run:
Enter your selection (a= Add New Employee, b = Punch in/out, c= Report, d = Exit):a
Enter your first name: Sa
Enter your last name: Ka
SaKawith employee id0
Enter your selection (a= Add New Employee, b = Punch in/out, c= Report, d = Exit):b
Welcome to the punch in/out screen
Enter your employee ID: 0
You are now punched in
Sa Ka your employee ID is 0 and your clock date and time is: Sun Jun 08 20:19:42 EDT 2014
Enter your selection (a= Add New Employee, b = Punch in/out, c= Report, d = Exit):a
Enter your first name: Ka
Enter your last name: Ma
KaMawith employee id1
Enter your selection (a= Add New Employee, b = Punch in/out, c= Report, d = Exit):b
Welcome to the punch in/out screen
Enter your employee ID: 1
You are now punched in
Ka Ma your employee ID is 1 and your clock date and time is: Sun Jun 08 20:19:42 EDT 2014
Enter your selection (a= Add New Employee, b = Punch in/out, c= Report, d = Exit):c
Welcome to the report screen.
Enter your selection (I = individual report or A= all employees):
a
In Consoldated Report
Enter your selection (a= Add New Employee, b = Punch in/out, c= Report, d = Exit):BUILD STOPPED (total time: 1 minute 8 seconds)
因此,當我現在轉到PC的E驅動器時,我只看到一個名為output.txt(最新修改時間)的文件,但其中沒有任何內容。 我試圖在循環后關閉緩沖區,但是沒有運氣。 另外,請建議您閱讀我寫入文件的數據
請指教!
謝謝
我不確定我是否理解您的問題,但是像這樣,您只能寫入一次文件,因為在寫入文件后將其關閉。 相反,您可以使用flush()方法來確保將內容寫入文件中。
考慮閱讀http://docs.oracle.com/javase/7/docs/api/java/io/BufferedWriter.html上的文檔。
在我的測試中,它工作正常。 但是改變bw.close(); 到bw.flush(); 因為在第一次輸入后輸出流將關閉。 並在第二次輸入時遇到了異常
馬上,我建議嘗試用E:\\output.txt
替換您的文件名。 我相信Windows文件路徑使用反斜杠。
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