[JAVA 코드] HashMap value값에 따라 그룹화

1. [파일]  : file_sample.txt

영수, 70 수영, 80 은지, 80 철수, 90 가영, 60

2. [자바 코드]

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import java.util.Map.Entry;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
 
    
public class convert {
 
    public static void main(String[] args) throws IOException {
        
        convert convert = new convert();
        convert.getFile();
        convert.grouping();
 
    }
 
    
    
        // 전역 변수 선언
        Map<String,String> Word = new HashMap<String,String>();
     
        // 파일 읽기
        public Map<String, String> getFile() throws FileNotFoundException {
     
        File file = new File("C:/Users/kej82/Desktop/sample.txt");
     
        try {
                System.out.println(file.getAbsoluteFile() + " reading...");
                BufferedReader inFiles = new BufferedReader(new InputStreamReader(new FileInputStream(file.getAbsolutePath()), "UTF8"));
                
                String line = "";
                while((line = inFiles.readLine()) != null) {
                 if(line.trim().length() > 0) {
                     String [] line2 = line.split(",");
                     Word.put(line2[0],line2[1]);
                 }
                }
                
                inFiles.close();
                
               } catch (Exception e) {
                e.printStackTrace();
               }
     
     
           return Word;
        }
     
     
        public void grouping() throws FileNotFoundException {
        // 그룹화_ mapbyValueGrouping
        Map<String, List<String>> wordTypeList = Word.keySet().stream()
                                            .collect(Collectors.groupingBy(Word::get, TreeMap::new, Collectors.toList()));
        
        System.out.println(wordTypeList);
     
        }
        

3. 결과