How can we read and write files in Java using Gson streaming API?

We can use Gson Streaming API to read and write files, which is based on the sequential reading and writing standard. JsonWriter and JsonReader are core classes built for streaming writing and reading in the Streaming API. JsonWriterWrites JSON encoded values ​​to the stream, one token at a time. The stream contains literal values ​​( strings, numbers, booleans, and null) as well as Start and End delimiters objects and arrays, JsonReaderRead JSON encoded values ​​as a token stream. This stream contains literal values ​​ ( strings, numbers, booleans, and nulls) and start and End delimiter. Tokens are traversed in depth-first order r, in the same order in which they appear in the JSON document.

Write files using JsonWriter

Example

import java.io.*;
import com.google.gson.stream.*;
public class JsonWriterTest {
   public static void main(String args[]) {
      JsonWriter writer;
      try {
         writer = new JsonWriter(new FileWriter("input.json"));
         writer.beginObject();
         writer.name("name").value("Adithya");
         writer.name("age").value(25);
         writer.name("technologies");
         writer.beginArray();
         writer.value("Java");
         writer.value("Scala");
         writer.value("Python");
         writer.endArray();
         writer.endObject();
         writer.close();
         System.out.println("Data write to a file successfully");
      } catch(Exception e) {
         e.printStackTrace();
      }
   }
}

Output

Data write to a file successfully<strong>
</strong>

##Read files using JsonReader

Example

import java.io.*;
import com.google.gson.stream.*;
public class JsonReaderTest {
   public static void main(String args[]) {
      JsonReader reader;
      try {
         reader = new JsonReader(new FileReader("input.json"));
         reader.beginObject();
         while(reader.hasNext()) {
            String name = reader.nextName();
            if(name.equals("name")) {
               System.out.println(reader.nextString());
            } else if(name.equals("age")) {
               System.out.println(reader.nextInt());
            } else if(name.equals("technologies")) {
               reader.beginArray();
               while(reader.hasNext()) {
                  System.out.println(reader.nextString());
               }
               reader.endArray();
            } else {
               reader.skipValue();
            }
         }
         reader.endObject();
         reader.close();
      } catch(Exception e) {
         e.printStackTrace();
      }
   }
}

Output

Adithya
25
Java
Scala
Python

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