HashMap.java

// Write a Java Program to diplay the Student Details from a text file in a HashMap and then store this information in an ArrayList.
/*HashMap<String, String> 
   Keys = Roll,
          Name, 
          Age,
          Marks,
          
    ArrayList<HashMap> 
    */

import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.HashMap;
import java.io.BufferedReader;
import java.io.FileReader;

public class StudentHashMap{
    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new File Reader("FilePath.txt"));
        StringBuffer sb = new StringBuffer();
        List<Map> studentArrayList = new ArrayList<>();
        String line;
        while((line = br.readLine()) != null){
            sb.append(line);
            sb.append("\n");
            
            String[] elements = line.split(", ");
            
            String roll = elements[0].trim();
            String name = elements[1].trim();
            String age = elements[2].trim();
            String marks = elements[3].trim();
           
            Map<String, String> studentDetailsMap = new HashMap<>();
            studentDetailsMap.put("Roll", roll);
            studentDetailsMap.put("Name", name);
            studentDetailsMap.put("Age", age);
            studentDetailsMap.put("Marks", marks);
            
            studentArrayList.add(studentDetailsMap);
        }
        br.close();
        for(Map map : studentArrayList){
            System.out.println(map);
        }
    }
}


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/*RollNo    Name     Age    Marks
   101    Chandana   18      90
    .         .       .       .
    .         .       .       .
    .         .       .       .
    .         .       .       .
    .         .       .       .
    .         .       .       .
    
    Create a text file with the above data and write a Java Program to read from the text file from each line and store it in a HashMap
    Now use an ArrayList to get the student details from each Map.*/
   
   
import java.util.List;
import java.util.Map;
import java.util.ArrayList;
import java.util.HashMap;
import java.io.BufferedReader;
import java.io.FileReader;
public class StudentHashMap{
    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new FileReader("FilePath.txt"));
        String buffer sb = new StringBuffer();
        List<Map> studentArrayList = new ArrayList<>();
        String line;
        
       while((line = br.readLine()) != null){
            sb.append(line);
            sb.append("\n");
            
            String[] elements = line.split(", ");
          
            String rollNo = elements[0];
            String name = elements[1];
            String age = elements[2];
            String marks = elements[3];
            
            Map<String, String> studentDetailsMap = new HashMap<>();
            studentArrayList.add(studentDetailsMap);
        }
        br.close();
        for(Map map : studentArrayList){
            System.out.println(map);
        }
    }
}