ProtoStuff不支持BigDecimal反序列化？

平时使用ProtoStuff作为序列化工具，对于一些POJO对象序列化，但是在实际使用中，发现针对BigDecimal对象进行序列化时却出现了问题

不管什么数，生成的byte数组都一样
无法正确反序列化

下面记录一下这个问题

1. 场景复现

我们使用的protostuff依赖如下

<dependency> <groupId>com.dyuproject.protostuff</groupId> <artifactId>protostuff-core</artifactId> <version>1.1.3</version> </dependency> <dependency> <groupId>com.dyuproject.protostuff</groupId> <artifactId>protostuff-runtime</artifactId> <version>1.1.3</version> </dependency>

写一个简单测试demo，如下

public static byte[] serialize(Object obj) {
    Schema schema = RuntimeSchema.getSchema(obj.getClass());
    LinkedBuffer buffer = LinkedBuffer.allocate(1048576); byte[] protoStuff; try {
        protoStuff = ProtostuffIOUtil.toByteArray(obj, schema, buffer);
    } catch (Exception var8) { throw new RuntimeException("Failed to serializer");
    } finally {
        buffer.clear();
    } return protoStuff;
} public static <T> T deserialize(byte[] paramArrayOfByte, Class<T> targetClass) { if (paramArrayOfByte != null && paramArrayOfByte.length != 0) {
        Schema<T> schema = RuntimeSchema.getSchema(targetClass);
        T instance = schema.newMessage();
        ProtostuffIOUtil.mergeFrom(paramArrayOfByte, instance, schema); return instance;
    } else { throw new RuntimeException("Failed to deserialize");
    }
} @Test public void testSer() { byte[] ans = serialize(new BigDecimal(20)); byte[] ans2 = serialize(new BigDecimal(120));

    System.out.println(new String(ans));
    System.out.println(new String(ans2));

    BigDecimal res = deserialize(ans, BigDecimal.class);
    System.out.println(res);
}

执行如下

2. 疑似原因与兼容方法

并没有找到具体的原因，在github上有一个issure: 其中回复为

Protostuff works on user-defined types (pojos), not on built-in jdk types.

上面的说法是ProtoStuff更多的是用于简单对象的序列化，而不是基础的jdk类型，因此推荐的是序列一个成员变量为BigDecimal的对象

接下来我们试一下，定义一个简单的对象，成员为BigDecimal的场景

@Data public static class InnerDecimal { private BigDecimal decimal; public InnerDecimal() {
    } public InnerDecimal(BigDecimal decimal) { this.decimal = decimal;
    }
} @Test public void testSer() { byte[] ans = serialize(new InnerDecimal(new BigDecimal(20.123))); byte[] ans2 = serialize(new InnerDecimal(new BigDecimal(120.1970824)));

    System.out.println(new String(ans));
    System.out.println(new String(ans2));

    InnerDecimal res = deserialize(ans, InnerDecimal.class);
    System.out.println(res);
}

测试输出如下

上面虽然可以正常工作，但与我们希望的差别有点大，序列化一个BigDecimal，还需要定义一个POJO包装他，有点麻烦；于是一个猥琐的方法就是在序列化和反序列化的时候，针对BigDeimal进行特殊处理

public static byte[] serialize(Object obj) { if (obj instanceof BigDecimal) {
        obj = ((BigDecimal) obj).toPlainString();
    }

    Schema schema = RuntimeSchema.getSchema(obj.getClass());
    LinkedBuffer buffer = LinkedBuffer.allocate(1048576); byte[] protoStuff; try {
        protoStuff = ProtostuffIOUtil.toByteArray(obj, schema, buffer);
    } catch (Exception var8) { throw new RuntimeException("Failed to serializer");
    } finally {
        buffer.clear();
    } return protoStuff;
} public static <T> T deserialize(byte[] paramArrayOfByte, Class<T> targetClass) { if (paramArrayOfByte != null && paramArrayOfByte.length != 0) {
        Schema schema; if (targetClass.isAssignableFrom(BigDecimal.class)) {
            schema = RuntimeSchema.getSchema(String.class);
            Object instance = schema.newMessage();
            ProtostuffIOUtil.mergeFrom(paramArrayOfByte, instance, schema); return (T) new BigDecimal((String) instance);
        } else {
            schema = RuntimeSchema.getSchema(targetClass);
            Object instance = schema.newMessage();
            ProtostuffIOUtil.mergeFrom(paramArrayOfByte, instance, schema); return (T) instance;
        }
    } else { throw new RuntimeException("Failed to deserialize");
    }
}