Question

我是java新手，我正在创建一个存储电影和电影信息的文件目录。电影和信息存储在如下文件中：

Movie Title 
Rating Year Reviews Month Day Year

第一行的标题和第二行的其他信息。因此，对于多部电影，它看起来像这样：

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。我有一个方法将电影打印到控制台，但我遇到了正确格式化电影的问题。电影信息的格式应如下：

   Star Wars     PG    1977   5 stars  1/5/2018

每列应正确对齐。标题，评级和年份应保持一致;的数量星星和日期对齐。

第一次打印出电影信息的确切方式，但是当我添加多部电影时，它会让事情变得混乱。这是我的代码，我相信问题出在listMovies方法中，我尝试格式化输出，但是我包含了所有代码，万一有些东西搞砸了。

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();
}

这是一部电影（运行程序一次）后的输出，它应该是它的外观：

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

这是在运行两次之后：

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)

这是在运行5次之后：

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

如果我理解正确的问题，解决方案很简单：在dirOut.hasNext（）循环中的System.out.printf（）下面添加以下行。

dirOut.nextLine();

您的输入模式有两行;这个额外的nextLine（）正确地在文件中前进。

使用Scanner解析文件中的输入。 JAVA

1 个答案: