[英]Is is possible use the same FileWriter file and write to it from multiple methods?
我正在從用戶那里獲取輸入文件和輸出文件,並嘗試從main方法和towerOfHanoiMoves方法寫入輸出文件。 我試圖將輸出變量作為參數傳遞給towerOfHanoiMoves方法,但始終出現錯誤。
我收到的錯誤是:
Exception in thread "main" java.lang.Error: Unresolved compilation problem: Unhandled exception type IOException
at TowerofHanoiRecursive.towerOfHanoiMoves(TowerofHanoiRecursive.java:72)
at TowerofHanoiRecursive.main(TowerofHanoiRecursive.java:41)
有沒有一種方法可以使我從兩個單獨的方法寫入同一輸出文件?
我嘗試使用PrintWriter,但這給了我同樣的事情。 我也嘗試過在towerOfHanoiMoves方法中刷新並關閉outStream,但這也不起作用。 我還導入了所有必需的java.io文件,但是由於某些原因,它們沒有顯示在這里。
public class TowerofHanoiRecursive{
public static void main(String[] args) throws IOException, EmptyFile,
FileNotFoundException{
int n; //number of disks
String rodLeft = "A", rodRight = "C", rodMiddle = "B";
FileReader inputStream = null;
FileWriter outputStream = null;
BufferedReader str = null;
try {
outputStream = new FileWriter(args[1]); // output file
inputStream = new FileReader(args[0]); // input file
str = new BufferedReader(inputStream);
String nextLine;
File newFile = new File(args[0]);
if (newFile.length()==0) { //Tests if input file is empty
//if file is empty, the EmptyFile exception will be thrown
throw new EmptyFile("Input file is empty");
}
while ((nextLine = str.readLine()) != null) {
outputStream.write("----------------------------------------"
+ "------------------------\n");
outputStream.write("Number of Disks in Starting Tower = "
+ nextLine);
n = Integer.parseInt(nextLine);
towerOfHanoiMoves(n, rodLeft, rodRight, rodMiddle,
outputStream);
}
}catch (FileNotFoundException e) {
outputStream.write("Input file not found.);
outputStream.flush();
if (outputStream != null) outputStream.close();
}catch (EmptyFile e) {
outputStream.write(e.getMessage());
outputStream.flush();
if (inputStream != null) inputStream.close();
if (outputStream != null) outputStream.close();
str.close();
} finally {
outputStream.write("");
outputStream.write("\n\nSuccess!);
outputStream.flush();
if (inputStream != null) inputStream.close();
if (outputStream != null) outputStream.close();
str.close();
}
}
public static void towerOfHanoiMoves(int n, String leftRod, String
rightRod, String MidRod, FileWriter outStream) {
if (n == 1) {
outStream.write("Move disk 1 from ....");
}
}
}
特殊的錯誤是write()
方法可以引發IOException
。 結果,必須捕獲或聲明該Exception。 因此,可以修改towerOfHannoiMoves
引發IOException
public static void towerOfHanoiMoves(int n,
String leftRod,
String rightRod,
String MidRod,
FileWriter outStream)
throws IOException
另一個注意事項:那里發布的代碼缺少一些引號。 例如,
outputStream.write("Input file not found.);
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