Question

我想要一个java程序来计算文件中最常见的元素

Answer 1

问题是“newCount”是String而不是Integer吗？

        String newCount = entry.getValue().toString();
        if(topN.containsKey(entry.getKey())){
            newCount += topN.get(entry.getKey());
        }

Answer 2

使用行Parser parser;，您声明了类Parser的变量，但是您没有初始化该变量。请改用Parser parser = new Parser();。

似乎也存在很多类型问题

String newCount = entry.getValue().toString();
if(topN.containsKey(entry.getKey())){
    newCount += topN.get(entry.getKey());
}
topN.put(entry.getKey(), newCount);

您似乎想要计算累计数，但如果您先将Integer转换为String，这将无效！此外，key的{{1}}将是一个值，因此Entry永远不能包含该密钥，因为它是topN Map和{Strings 1}}，即使是这样，您如何向Actors（或Actor）添加Integer？最后，正如其他人所指出的那样，String将失败，因为密钥的类型和值都与put的类型不匹配。

如果不知道其他课程（Map，Sketch，Value等）是做什么的，那么很难给出如何解决问题的明确建议。

Answer 3

topN被声明为Map<String, Actor>。因此密钥必须为String，且值必须为Actor类型。

在topN.put(entry.getKey(), newCount);中，newCount（字符串）不是Actor。另请检查entry.getKey()是否为字符串。

public class Parser {

        private BufferedReader bf;
        private static final String ACTOR_MOVIE_FILE = "actormovie.txt";
        private Map<String, Actor> actors;

        //this is the input file size
        int fileSize = ACTOR_MOVIE_FILE.length();

        public Parser() {
                try {
                        bf = new BufferedReader(new FileReader(ACTOR_MOVIE_FILE), 32768);
                } catch (FileNotFoundException e) {
                        JOptionPane.showMessageDialog(null, "file cannot be located ", "File not found exception", JOptionPane.ERROR_MESSAGE);
                }
                actors = new Hashtable<String, Actor>(1713251);
        }

        /**
         * this reads data on a line one at a time
         * @return actors in the hash table, with the name of an actor as a,
         * and value as the actor object
         */
        public Map<String, Actor> readLines() {
                 String line=" ";

                while(true){
                        try {
                                line = bf.readLine();
                        } catch (IOException e) {
                                JOptionPane.showMessageDialog(null, "deadlock file not in proper format", "we have error reading the file", JOptionPane.ERROR_MESSAGE);
                        }

                        if(line == null){ 
                            break; 
                            }

                        String[] tokens = line.split("/");        
                        assemblyLines(tokens);
                }
                try { 
                    bf.close(); 

                } catch(IOException e){

                }
                return actors;
        }

        /**
         * from a line we get stringTokenizers parse to the data structures. Film is described as a
         * stringTokenizer with film object created from it. There are actors which are as well 
         * stringTokenizers created as actor object
         * there is an actor table that controls entry space. In occurrences of other actors , 
         * the object is altered, other than that 
         * objected is created and appended to the table
         * @param stringTokenizer makes the text file divided into individual components
         */
        public void assemblyLines(String[] stringTokenizer){
                Film film = new Film(stringTokenizer[0]);

                for(int i = 1; i < stringTokenizer.length;i++){

                        Actor actor;
                        String actorName = stringTokenizer[i];

                        if(actors.containsKey(actorName)){                        
                                actor = actors.get(actorName);
                        } else {
                                actor = new Actor(actorName);
                                actors.put(actorName, actor);
                        }
                        film.addActor(actor);
                        actor.addFilm(film);
                }
        }        

}

用于计算最常见元素的Java程序

3 个答案: