Second week: statistical improvement of Word frequency

Demand:

1. Enter commands in the console;

2. The input must be a path or a file that already exists on the hard disk;

3. Enter the directory name to count the directories;
4. Enter the file in the file to count the words inside.

Analysis:
1. Read the file using the BufferedReader class to read by line;
2. Define a regular expression to filter the string symbol;
3. Create HashMap;
4. Use StringTokenizer to participle;
5. Add the words to the haspmap stored key value pairs;
6, traverse hashmap output result;
7. Let the user enter a path in the console;
8. The user input path to judge if it is a directory to traverse the directory, in the statistics inside the word;
9. Otherwise, the file is traversed, and the word in the statistics file is sorted using the Collections.sort () method.

Specific code implementation:

1. Determine whether the input is a directory, directory traversal and statistics.

1File File =NewFile (URL);//Create a File object2         if(File.isdirectory ()) {//determine if the file object is a directory3string[] names = File.list ();//gets the file name of all files under the directory4              for(String name:names) {5 System.out.println (name);6                 if(!hashmap.containskey (name)) {//determine if there is a word in the HashMap7Hashmap.put (Name,NewInteger (1)); 8                     //if the value of Word is not treated as a key, the key value is recorded once9                     Ten}Else{     One                     intK=hashmap.get (name). Intvalue () +1;//If you have the value of Word as a key, the key value is added on the original basis AHashmap.put (Name,NewInteger (k));  -                      -                 }     the                       for(String key:hashMap.keySet ()) { -                             //print words and the number of words -SYSTEM.OUT.PRINTLN (key + ": \ T" +Hashmap.get (key)); -                         } +                  -              +             } A              at              -}

2. If the input is a file, read the word inside the file.

        //The words in the statistics file at the time of the document            Else{bufferedreader br=NewBufferedReader (Newfilereader (URL));                   String value;  while((Value=br.readline ())! =NULL){//Read the text and read a line until it is finished readingValue=value.replaceall (Fregex, "");//use spaces instead of some special symbols in text//use StringTokenizer to participle (the application class StringTokenizer used to separate strings)StringTokenizer Tokenizer =NewStringTokenizer (value);  while(Tokenizer.hasmoretokens ()) {String Word=Tokenizer.nexttoken (); if(!hashmap.containskey (Word)) {//determine if there is a word in the HashMapHashmap.put (Word,NewInteger (1));//if the value of Word is not treated as a key, the key value is recorded once}Else{                                     intK=hashmap.get (Word). Intvalue () +1;//If you have the value of Word as a key, the key value is added on the original basisHashmap.put (Word,NewInteger (k)); }                                               }                     }                 

3. Count the words and sort them.

arraylist<map.entry<string, integer>> Com =NewArraylist<map.entry<string, integer>>(Hashmap.entryset ()); //sort using the Sort method inside the Collections tool classCollections.sort (Com,NewComparator<map.entry<string, integer>>()                    {                             Public intCompare (map.entry<string, integer> O1, map.entry<string, integer>O2) {                                return(O2.getvalue ()-O1.getvalue ());                        };                    }); System.out.println ("Total:" + hashmap.size ());//traverse HashMap, Output results                    intCount = 50;  for(Map.entry<string, integer>comp:com) {                            if(count--< 0) Break; System.out.println (Comp.getkey ()+ ": \ T" +Comp.getvalue ()); }                                                      }           }

4. Enter the command in the console.

/**      * Console input command     * can be a directory or a file     *      * */public    static  String Scan () {        new  Scanner (system.in);          System.out.print ("Please enter directory or file:");          = Sc.next ();           return text;    }}

Operation Result:

1. Read the directory.

2. Read the files in the directory.

Second week: statistical improvement of Word frequency