分布式开发

序列化/反序列化 - 实现内存对象 - 二进制数据的转换，二进制数据用于存储、持久化、网络传输。
技术选型要素：①序列化空间开销(压缩比) ②序列化时间损耗(性能需求) ③是否跨平台 ④使用的难易程度 ⑤是否需要可读性

Java序列化

// 序列化对象需实现Serializable接口，可通过transient标签标注属性无需序列化，建议设置序列化UUID
public class JavaSerializer implements ISerializer {
    public <T> byte[] serialize(T obj) {
        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
             ObjectOutputStream oos = new ObjectOutputStream(baos);){
            oos.writeObject(obj);
            return baos.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return new byte[0];
    }

    public <T> T deserialize(byte[] data) {
        try (ByteArrayInputStream bais = new ByteArrayInputStream(data);
             ObjectInputStream ois = new ObjectInputStream(bais);){
            return (T)ois.readObject();
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }
}

XML序列化

// 当前demo采用Xstream组件
public class XMLSerializer implements ISerializer{
    XStream stream=new XStream(new DomDriver());
    @Override
    public <T> byte[] serialize(T obj) {
        return stream.toXML(obj).getBytes();
    }

    @Override
    public <T> T deserialize(byte[] data) {
        return (T)stream.fromXML(new String(data));
    }
}

Json序列化

// Fastjson组件，性能最高，但稳定性不如Gson和Jackson
public class FastjsonSerializer implements ISerializer{
    public <T> byte[] serialize(T obj) {
        return JSON.toJSONBytes(obj);
    }

    public <T> T deserialize(byte[] data) {
        return JSON.parseObject(data, User.class);
    }
}

Hessian序列化

public class HessianSerializer implements ISerializer{
    @Override
    public <T> byte[] serialize(T obj) {
        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();){
            HessianOutput oos = new HessianOutput(baos);
            oos.writeObject(obj);
            return baos.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return new byte[0];
    }

    @Override
    public <T> T deserialize(byte[] data) {
        try (ByteArrayInputStream bais = new ByteArrayInputStream(data);){
            HessianInput ois = new HessianInput(bais);
            return (T)ois.readObject();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}

protobuf序列化

特殊的序列化组件，需要额外的脚本支持(压缩率快而高)

int压缩算法：zigzag和varint算法

    private static void testProtobufSerializer() throws InvalidProtocolBufferException {
        UserProto.User user = UserProto.User.newBuilder().setName("kiqi").setAge(18).setStatus(-200).build();
        byte[] bytes = user.toByteArray();
        System.out.println(Arrays.toString(bytes));

        UserProto.User userRever = UserProto.User.parseFrom(bytes);
        System.out.println(userRever.toString());
    }