使用掃描儀分析文件中的輸入。 JAVA

Question

我是java的新手，並且正在創建一個文件目錄，該目錄存儲電影和有關電影的信息。 電影和信息存儲在這樣的文件中：

Movie Title 
Rating Year Reviews Month Day Year

第一行的標題，第二行的其他信息。 因此，對於多部電影，它看起來像這樣：

Movie Title
Rating Year Reviews Month Day Year
Movie Title
Rating Year Reviews Month Day Year
Movie Title
Rating Year Reviews Month Day Year

...等等。 我有一種將影片打印到控制台的方法，但是我遇到了正確格式化影片的問題。 電影信息應采用以下格式：

   Star Wars     PG    1977   5 stars  1/5/2018

每列應正確對齊。 標題，等級和年份應保持對齊； 星號和日期正確對齊。

第一次它完全按照我想要的方式打印電影信息，但是當我添加多部電影時，事情就變得混亂了。 這是我的代碼，我相信問題出在listMovies方法中，我嘗試格式化輸出，但是我包括了所有代碼，以防其他地方發生混亂。

public class Directory 
{
   private static final String dir = "data/cs2410-directory.data";
   String mTitle,mRat,mRel,mRev,mM,mD,mY;

public Directory()
{
    mTitle = "Movie Title";
    mRat = "Rating";
    mRel = "Year";
    mRev = "Reviews";
    mM = "Month";
    mD = "Day";
    mY ="Year";
    insertMovie();
    listMovies();
}


private void insertMovie()
{
    PrintWriter dirIn = null;

    try
    {
        dirIn = new PrintWriter(new FileOutputStream(dir,true));
    }
    catch (FileNotFoundException e)
    {
        e.printStackTrace();
    }
    dirIn.println(mTitle);
    dirIn.println(mRat+" "+mRel+" "+mRev+" "+mM+" "+mD+" "+mY);
    dirIn.close();
    System.out.print("The following movie has been added to the directory:\n");
    System.out.print(mTitle+" ("+mRel+") "+mRat+"\n");
    System.out.print("Stars: "+mRev+"\n");
    System.out.print("Last Watched: "+mM+"/"+mD+"/"+mY+"\n");
}

private void listMovies()
{
    Scanner dirOut = null;

    try
    {
        dirOut = new Scanner(new FileReader(dir));
    }
    catch (FileNotFoundException e)
    {
        e.printStackTrace();
    }
    while (dirOut.hasNext()) //PROBLEM
    {
        System.out.printf("%-15s%-10s%-10s%5s%10s/%s/%s\n", dirOut.nextLine(),dirOut.next()
                ,dirOut.next(),dirOut.next(),dirOut.next(),dirOut.next(),dirOut.next());
    }
    dirOut.close();
}

public static void main(String[] args)
{
    new Directory();
}

這是一部電影（一次運行程序）后的輸出，應該是這樣的樣子：

The following movie has been added to the directory:
Movie Title (Year) Rating
Stars: Reviews
Last Watched: Month/Day/Year
Movie Title    Rating    Year      Reviews     Month/Day/Year

這是運行兩次之后的結果：

The following movie has been added to the directory:
Movie Title (Year) Rating
Stars: Reviews
Last Watched: Month/Day/Year
Movie Title    Rating    Year      Reviews     Month/Day/Year
               Movie     Exception in thread "main" java.util.NoSuchElementException
Title     Rating      Year/Reviews/Month
    at java.base/java.util.Scanner.throwFor(Scanner.java:858)
    at java.base/java.util.Scanner.next(Scanner.java:1381)
    at cs2410.assn3.directory.Directory.listMovies(Directory.java:71)
    at cs2410.assn3.directory.Directory.<init>(Directory.java:32)
    at cs2410.assn3.directory.Directory.main(Directory.java:79)

這是運行5次后的結果：

The following movie has been added to the directory:
Movie Title (Year) Rating
Stars: Reviews
Last Watched: Month/Day/Year
Movie Title    Rating    Year      Reviews     Month/Day/Year
               Movie     Title     Rating      Year/Reviews/Month
 Day Year      Movie     Title     Rating      Year/Reviews/Month
 Day Year      Movie     Title     Rating      Year/Reviews/Month
 Day Year      Movie     Title     Rating      Year/Reviews/Month
 Exception in thread "main" java.util.NoSuchElementException
    at java.base/java.util.Scanner.throwFor(Scanner.java:858)
    at java.base/java.util.Scanner.next(Scanner.java:1381)
    at cs2410.assn3.directory.Directory.listMovies(Directory.java:71)
    at cs2410.assn3.directory.Directory.<init>(Directory.java:32)
    at cs2410.assn3.directory.Directory.main(Directory.java:79)

Answer 1

如果我正確理解了該問題，則解決方案非常簡單：在dirOut.hasNext（）循環中的System.out.printf（）下面添加以下行。

dirOut.nextLine();

您的輸入模式有兩行； 這個額外的nextLine（）可以正確地瀏覽文件。