protostuff序列化map_为什么要实现序列化

大家好，又见面了，我是你们的朋友全栈君。

这几天在看rpc框架的东西，一哥们写的轻量级rpc框架（http://my.oschina.net/huangyong/blog/361751?fromerr=NpC3phqY）实现，写的rpc很不错，就跟着撸了遍代码，里面用到的序列化工具是protostuff，之前我们项目供应商接口用的xml，没用过protostuff，拿过来研究下，写个demo示例，以后再需要的话，也可以拿过来用。

常用的序列化基本是xml，protobuf，protostuff，xml用起来简单方便，顺手就用，但是序列化/反序列化的性能不行，protobuf，Google出品，性能比xml肯定好，用于不同语言，不同平台的交互，需要预编译，用起来麻烦，改的东西都要编译下，感觉不适合数据结构经常变动，后来就来了protostuff，无需预编译，就可以对javabean进行序列化和反序列化，性能更好。

上代码,添加maven依赖：

	<!-- Protostuff -->
	<dependency>
	    <groupId>com.dyuproject.protostuff</groupId>
	    <artifactId>protostuff-core</artifactId>
	    <version>1.0.8</version>
	</dependency>
	<dependency>
	    <groupId>com.dyuproject.protostuff</groupId>
	    <artifactId>protostuff-runtime</artifactId>
	    <version>1.0.8</version>
	</dependency>
	
		<!-- Objenesis -->
	<dependency>
	    <groupId>org.objenesis</groupId>
	    <artifactId>objenesis</artifactId>
	    <version>2.1</version>
	</dependency>

ps：一般反射实例化java类的时候，newInstance如果java类没有默认构造函数，肯定不行，而objenesis用来对实例化java类，无需默认构造函数，官网：http://objenesis.org/tutorial.html，用起来很简单

SerializationUtils，序列化工具类，上面那个哥们rpc里面用的：

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.objenesis.Objenesis;
import org.objenesis.ObjenesisStd;

import com.dyuproject.protostuff.LinkedBuffer;
import com.dyuproject.protostuff.ProtostuffIOUtil;
import com.dyuproject.protostuff.Schema;
import com.dyuproject.protostuff.runtime.RuntimeSchema;

public class SerializationUtils {

    private static Map<Class<?>, Schema<?>> cachedSchema = new ConcurrentHashMap<Class<?>, Schema<?>>();
    
    private static Objenesis objenesis = new ObjenesisStd(true);
    
    private SerializationUtils(){
    }
    
    @SuppressWarnings("unchecked")
    private static <T> Schema<T> getSchema(Class<T> cls){
        Schema<T> schema = (Schema<T>)cachedSchema.get(cls);
        if(schema == null){
            schema = RuntimeSchema.createFrom(cls);
            if(schema != null){
                cachedSchema.put(cls, schema);
            }
        }
        return schema;
    }
    
    @SuppressWarnings("unchecked")
    public static <T> byte[] serializer(T obj){
        Class<T> cls = (Class<T>) obj.getClass();
        LinkedBuffer buffer = LinkedBuffer.allocate(LinkedBuffer.DEFAULT_BUFFER_SIZE);
        try{
            Schema<T> schema = getSchema(cls);
            return ProtostuffIOUtil.toByteArray(obj, schema, buffer);
        }catch (Exception e) {
            throw new IllegalStateException(e.getMessage(), e);
        }finally{
            buffer.clear();
        }
    }
    
    public static <T> T deserializer(byte[] data, Class<T>cls){
        try{
            T message = (T)objenesis.newInstance(cls);
            Schema<T> schema = getSchema(cls);
            ProtostuffIOUtil.mergeFrom(data, message, schema);
            return message;
        }catch (Exception e) {
            throw new IllegalStateException(e.getMessage(), e);
        }
    }
}

下面是几个javabean

public class OrderInfo {
    /**
     * 订单流水
     */
    private String orderNo;
    /**
     * 订单概要信息
     */
    private Map<String, Object> orderItem;
    /**
     * 订单扩展信息
     */
    private List<OrderExt> orderExts;
    
    /**
     * 收货信息
     */
    private DelieryAddress address;

    //getter,setter,toString方法

public class OrderExt {
    /**
     * 订单流水
     */
    private String orderNo;
    /**
     * 商品编码
     */
    private String goodsNo;
    
    //getter,setter,toString方法

public class DelieryAddress {

    /**
     * 收货地址
     */
    private String address;
    /**
     * 收货人
     */
    private String consigneeName;
    /**
     * 送达时间
     */
    private Date expectTime;
    
    //getter,setter,toString方法

测试类：

public class ProtostuffTest {

    public static void main(String[] args) {
        OrderInfo oldOrder = createOrder();
        System.out.println(oldOrder);
        
        byte[] orderinfo = SerializationUtils.serializer(oldOrder);
        
        OrderInfo neOrder = SerializationUtils.deserializer(orderinfo, OrderInfo.class);
        
        System.out.println(neOrder);
        System.out.println(neOrder.getOrderNo() == null ? "y" : "n");
    }
    
    private static OrderInfo createOrder(){
        OrderInfo orderInfo = new OrderInfo();
        DelieryAddress delieryAddress = new DelieryAddress();
        List<OrderExt> orderExts = new LinkedList<OrderExt>();
        
        for(int i=0; i<2; i++){
            OrderExt orderExt = new OrderExt();
            orderExt.setGoodsNo("343434");
            orderExt.setOrderNo("12345");
            orderExts.add(orderExt);
        }
        
        delieryAddress.setAddress("江苏南京");
        delieryAddress.setConsigneeName("熊猫");
        delieryAddress.setExpectTime(new Date());
        
        Map<String, Object> orderItem = new HashMap<String, Object>();
        orderItem.put("google","google.com");
        orderItem.put("baidu", "baidu.com");
        
        orderInfo.setOrderItem(orderItem);
        orderInfo.setAddress(delieryAddress);
        orderInfo.setOrderExts(orderExts);
        
        return orderInfo;
    }

}

主要测试javabean字段里面null/string/list/map或其他javabean做为参数，看看是否能够正确序列化和反序列。

结果完全没问题：

protostuff序列化map_为什么要实现序列化