How Java uses Apache Avro serialization and deserialization

Apache Avro is a data serialization system that provides a language independent and platform independent data serialization format. Its design goal is to provide efficient data compression and fast serialization/deserialization processes. Avro uses a compact binary format for serialization and supports dynamic typing. The key concepts of Avro include Schema and codec. Schema defines the structure of data, which can be written in JSON format. Each data item has an associated Schema. Schemes can be nested and referenced from other schemas. The definition of Schema plays an important role in data serialization and deserialization. The codec is responsible for converting data from object representations in memory to Avro binary format and restoring it to objects when needed. Avro provides a variety of codecs, including binary encoders, JSON encoders, and language specific encoders. The following are common methods for serialization and deserialization using Apache Avro: 1. Define Schema: First, you need to define the schema of the data. Schema can be written using Avro's Schema definition language or directly in JSON format. 2. Create data objects through a schema: Use a defined schema to create data objects. 3. Serialization: Encode data objects into Avro binary format. 4. Deserialization: Decode Avro binary format into a data object. The following is a simple example of using Apache Avro: 1. Define Schema: String schemaStr = "{\"type\":\"record\",\"name\":\"Person\",\"fields\":[{\"name\":\"name\",\"type\":\"string\"},{\"name\":\"age\",\"type\":\"int\"}]}"; Schema schema = new Schema.Parser().parse(schemaStr); 2. Create data objects through Schema: GenericRecord person = new GenericData.Record(schema); person.put("name", "Alice"); person.put("age", 25); 3. Serialization: ByteArrayOutputStream out = new ByteArrayOutputStream(); DatumWriter<GenericRecord> writer = new GenericDatumWriter<>(schema); BinaryEncoder encoder = EncoderFactory.get().binaryEncoder(out, null); writer.write(person, encoder); encoder.flush(); out.close(); byte[] serializedBytes = out.toByteArray(); 4. Deserialization: ByteArrayInputStream in = new ByteArrayInputStream(serializedBytes); DatumReader<GenericRecord> reader = new GenericDatumReader<>(schema); BinaryDecoder decoder = DecoderFactory.get().binaryDecoder(in, null); GenericRecord deserializedPerson = reader.read(null, decoder); in.close(); The above code uses Avro's Java API for serialization and deserialization operations. Regarding dependencies, Avro's core library and related codecs need to be used. The following Maven dependencies can be added to the pom.xml file of the project: <dependency> <groupId>org.apache.avro</groupId> <artifactId>avro</artifactId> <version>1.10.2</version> </dependency> <dependency> <groupId>org.apache.avro</groupId> <artifactId>avro-tools</artifactId> <version>1.10.2</version> </dependency> This enables the use of Apache Avro for data serialization and deserialization operations in Java projects.