We will look into the Method that allows us to read the HashMap Text from the file or how we can De-serialised the File
De-Serialization: Here we are reproducing the HashMap object and it’s content from a serialized file.
Approach:
Firstly the method/Function HashMapFromTextFile will have the Method bufferedReader which read the Line of the text File and insert into the map and then return the Map
bf = new BufferedWriter( new FileWriter(file_name) );
- Firstly we call the BufferedReader to read each line.
- At each Line, We have the Key-Value Pair. So, Now split it by “:” and same time put the key and Value to the map
- and return the Map
Java
// Java program to reading// text file to HashMap import java.io.*;import java.util.*; class GFG { final static String filePath = "F:/Serialisation/write.txt"; public static void main(String[] args) { // read text file to HashMap Map<String, String> mapFromFile = HashMapFromTextFile(); // iterate over HashMap entries for (Map.Entry<String, String> entry : mapFromFile.entrySet()) { System.out.println(entry.getKey() + " : " + entry.getValue()); } } public static Map<String, String> HashMapFromTextFile() { Map<String, String> map = new HashMap<String, String>(); BufferedReader br = null; try { // create file object File file = new File(filePath); // create BufferedReader object from the File br = new BufferedReader(new FileReader(file)); String line = null; // read file line by line while ((line = br.readLine()) != null) { // split the line by : String[] parts = line.split(":"); // first part is name, second is number String name = parts[0].trim(); String number = parts[1].trim(); // put name, number in HashMap if they are // not empty if (!name.equals("") && !number.equals("")) map.put(name, number); } } catch (Exception e) { e.printStackTrace(); } finally { // Always close the BufferedReader if (br != null) { try { br.close(); } catch (Exception e) { }; } } return map; }} |
