Question

我正在尝试编写一个加载电影数据库文件的程序，然后将该信息拆分为电影标题，年份和所有关联的actor。我将所有信息分开，但是我将问题转换为int，这是将字符串转换为int的问题。年份字符串的格式是（****），*是一年，例如1999.当我尝试使用解析时，我得到一个数字格式异常。我试过替换括号，但它只是给了我更多的错误！有什么想法吗？

public class MovieDatabase {

ArrayList<Movie> allMovie = new ArrayList<Movie>();

//Loading the text file and breaking it apart into sections
public void loadDataFromFile( String aFileName) throws FileNotFoundException{
    Scanner theScanner = new Scanner(aFileName);
    theScanner = new Scanner(new FileInputStream("cast-mpaa.txt"));

    while(theScanner.hasNextLine()){
        String line = theScanner.nextLine();
        String[] splitting = line.split("/" );
        String movieTitleAndYear = splitting[0];
        int movieYearIndex = movieTitleAndYear.indexOf("(");
        String movieYear = movieTitleAndYear.substring(movieYearIndex);
        System.out.println(movieYear);
        //this is where I have issues
        int theYear = Integer.parseInt(movieYear);
        String movieTitle = movieTitleAndYear.substring(0, movieYearIndex);
        ArrayList<Actor> allActors = new ArrayList<Actor>();
        for ( int i = 1; i < splitting.length; i++){
            String[] names = splitting[i].split(",");
            String firstName = names[0];
            Actor theActor = new Actor(firstName);
            ArrayList<Actor> allActor = new ArrayList<Actor>();
            allActor.add(theActor);
        }

        Movie theMovie = new Movie(movieTitle, theYear, allActors);
        allMovie.add(theMovie);

    }       
    theScanner.close();
}

输出：

(1967)

以下是我遇到的错误：

Exception in thread "main" java.lang.NumberFormatException: For input string: "(1967)"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:481)
at java.lang.Integer.parseInt(Integer.java:527)
at MovieDatabase.loadDataFromFile(MovieDatabase.java:27)

Answer 1

数字周围有括号。您可以更正文件，也可以使用以下方法删除括号：

String str = "(1967)";
System.out.println(str.substring(1, str.length()-1));
Output:
1967

在您的代码中，您使用了：

int movieYearIndex = movieTitleAndYear.indexOf("(");
String movieYear = movieTitleAndYear.substring(movieYearIndex);

因此，如果我的movieTitleAndYear字符串是＆＃34; hi（1947）＆＃34;，indexOf将给出索引＆＃34;（＆＃34; as 3和substring将开始从索引3读取字符串，其中包括＆＃34;（＆＃34;。您可以避免打开括号的一种方法是将子字符串行更改为：

String movieYear = movieTitleAndYear.substring(movieYearIndex + 1);//but still you have closing bracket.

如果您确定它总是四位数，那么您可以执行以下操作：

String movieYear = movieTitleAndYear.substring(movieYearIndex + 1, movieYearIndex  + 5);

Answer 2

您的substring来电当前用括号括起一年，例如(1967)。您可以通过调用substring variant that accepts an endIndex来避免这种情况，只需获取年份的四位数字：

String movieYear = 
    movieTitleAndYear.substring(movieYearIndex + 1, // to get rid of "("
                                movieYearIndex + 5 // to get rid of ")" 
                               );

Answer 3

您需要为“）”添加indexof。代码段：

int movieYearOpenBracesIndex = movieTitleAndYear.indexOf("(");
int movieYearCloseBracesIndex = movieTitleAndYear.indexOf(")");
String movieYear = movieTitleAndYear.substring(movieYearOpenBracesIndex + 1, movieYearCloseBracesIndex);
System.out.println(movieYear);

这将给出确切的年份。例如1967年

数字格式问题，新手项目

3 个答案: