我有一个不同长度的字符串arraylist。我想组字符串

Question

我有一个不同长度的字符串数组列表。我想将字符串分组，并将它们放入相应长度的不同ArrayList中，并将每个组的ArrayList映射到hashmap。 like：map.put（4，list4）;是指列出4的长度是所有单词4.

Answer 1

package javaapplication13; 

import java.io.BufferedReader; 
import java.io.FileNotFoundException; 
import java.io.FileReader; 
import java.io.IOException; 
import java.util.ArrayList; 
import java.util.HashMap; 

public class JavaApplication13 { 

    public static void main(String[] args) { 
    // TODO code application logic here 
    BufferedReader br; 
    String strLine; 
    ArrayList<String> arr =new ArrayList<>(); 
    HashMap<Integer,ArrayList<String>> hm = new HashMap<>(); 
    try { 
     br = new BufferedReader(new FileReader("words.txt")); 
     while((strLine = br.readLine()) != null){ 
      arr.add(strLine); 
     } 
    } catch (FileNotFoundException e) { 
     System.err.println("Unable to find the file: fileName"); 
    } catch (IOException e) { 
     System.err.println("Unable to read the file: fileName"); 
    } 


    ArrayList<Integer> lengths = new ArrayList<>(); //List to keep lengths information 


    System.out.println("Total Words: "+arr.size()); //Total waords read from file 

    int i=0; 
    while(i<arr.size()) //this loop will itrate our all the words of text file that are now stored in words.txt 
    { 
     boolean already=false; 
     String s = arr.get(i); 
     //following for loop will check if that length is already in lengths list. 
     for(int x=0;x<lengths.size();x++) 
     { 
      if(s.length()==lengths.get(x)) 
       already=true; 
     } 
     //already = true means file is that we have an arrayist of the current string length in our map 
     if(already==true) 
     { 

      hm.get(s.length()).add(s); //adding that string according to its length in hm(hashmap) 
     } 
     else 
     { 
       hm.put(s.length(),new ArrayList<>()); //create a new element in hm and the adding the new length string 
       hm.get(s.length()).add(s); 
       lengths.add(s.length()); 

     } 

     i++; 
    } 
    //Now Print the whole map 
    for(int q=0;q<hm.size();q++) 
    { 
     System.out.println(hm.get(q)); 
    } 
    } 

}