将 Hash Map 中的值存储到文本文件中

Question

I have created a class that allows the user to create and store compounds into a Hash Map and now I want to create another class that allows me to take the values stored in that Hash Map and save them into a text file. I'm not sure if this is needed, but here is the code for the first class that I created containing the Hash Map:

package abi;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
public class ChemicalComp {
public static void main(String[] args) throws IOException{
       BufferedReader br = new BufferedReader(new InputStreamReader(System.in));  
       Map<String, String> data = new HashMap<String, String>();
       while(true){
           String readinput=br.readLine();
           if(readinput.equals(""))
               break;
                String input = readinput.replaceAll("\"", "");
                String array[]=input.split(", ");
                String compound=array[0];
                String formula="";
      
                for(int i=1;i<array.length;i++){
                    if(!array[i].equals("1")){
                        formula+=array[i];
                    }
                }
                data.put(compound, formula);
       }
       if(!data.isEmpty()) {
           @SuppressWarnings("rawtypes")
           Iterator it = data.entrySet().iterator();
           while(it.hasNext()) {
               @SuppressWarnings("rawtypes")
               Map.Entry obj = (Entry) it.next();
               System.out.println(obj.getKey()+":"+obj.getValue());
           }
       }

       }


}

I'm not too familiar with text files, but I have done some research and this is what I've gotten so far. I know its pretty basic and that I will probably need some type of getter method, but I'm not sure where to incorporate it into what I have. Here is what I have for the class containing the text file:

package abi;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.IOException;
public class CompoundManager {
private String path;
private boolean append_to_file = false;

public CompoundManager(String file_path) {
    path = file_path;
    
}
public CompoundManager(String file_path, boolean append_value){
    path = file_path; 
    append_to_file = append_value;
}
public void WriteToFile (String textLine) throws IOException{
    
FileWriter Compounds = new FileWriter(path, append_to_file);
PrintWriter print_line = new PrintWriter (Compounds);

print_line.printf("%s" + "%n", textLine);

print_line.close();
}
}

Answer 1

I can't understand what your program does but you can use a buffered writer for it. Just create a try-catch block and wrap a filewriter in a bufferedwriter like this:

try (BufferedWriter br = new BufferedWriter(new FileWriter(new File("filename.txt"))))
{
     for (Map.Entry<Integer, String> entry : map.entrySet()) {
        int key = entry.getKey();
        String value = entry.getValue();
        br.write(key + ": " + value);
        br.newLine();
    }
} catch (Exception e) {
    printStackTrace();
}