使自定义.NET Exception可序列化的正确方法是什么?

3xiyfsfu  于 2023-05-19  发布在  .NET
关注(0)|答案(8)|浏览(167)

更具体地说,当异常包含自定义对象时,这些对象本身可能是或可能不是可序列化的。
举个例子:

public class MyException : Exception
{
    private readonly string resourceName;
    private readonly IList<string> validationErrors;

    public MyException(string resourceName, IList<string> validationErrors)
    {
        this.resourceName = resourceName;
        this.validationErrors = validationErrors;
    }

    public string ResourceName
    {
        get { return this.resourceName; }
    }

    public IList<string> ValidationErrors
    {
        get { return this.validationErrors; }
    }
}

如果此Exception被序列化和反序列化,则两个自定义属性(ResourceNameValidationErrors)将不会保留。属性将返回null

自定义异常序列化的实现有没有通用的Code Pattern?

axzmvihb

axzmvihb1#

基本实现,无自定义属性

SerializableExceptionWithoutCustomProperties.cs:

namespace SerializableExceptions
{
    using System;
    using System.Runtime.Serialization;

    [Serializable]
    // Important: This attribute is NOT inherited from Exception, and MUST be specified 
    // otherwise serialization will fail with a SerializationException stating that
    // "Type X in Assembly Y is not marked as serializable."
    public class SerializableExceptionWithoutCustomProperties : Exception
    {
        public SerializableExceptionWithoutCustomProperties()
        {
        }

        public SerializableExceptionWithoutCustomProperties(string message) 
            : base(message)
        {
        }

        public SerializableExceptionWithoutCustomProperties(string message, Exception innerException) 
            : base(message, innerException)
        {
        }

        // Without this constructor, deserialization will fail
        protected SerializableExceptionWithoutCustomProperties(SerializationInfo info, StreamingContext context) 
            : base(info, context)
        {
        }
    }
}

完整实现,自定义属性

自定义可序列化异常(MySerializableException)和派生的sealed异常(MyDerivedSerializableException)的完整实现。
关于此实现的要点总结如下:
1.您必须使用[Serializable]属性修饰每个派生类-此属性不是从基类继承的,如果未指定,序列化将失败,并显示SerializationException,声明 “程序集Y中的类型X未标记为可序列化"
1.必须实现自定义序列化[Serializable]属性本身是不够的-Exception实现了ISerializable,这意味着派生类还必须实现自定义序列化。这涉及两个步骤:
1.提供序列化构造函数。如果你的类是sealed,这个构造函数应该是private,否则它应该是protected,以允许访问派生类。
1.重写GetObjectData(),并确保在最后调用base.GetObjectData(info, context),以便让基类保存自己的状态。

SerializableExceptionWithCustomProperties.cs:

namespace SerializableExceptions
{
    using System;
    using System.Collections.Generic;
    using System.Runtime.Serialization;
    using System.Security.Permissions;

    [Serializable]
    // Important: This attribute is NOT inherited from Exception, and MUST be specified 
    // otherwise serialization will fail with a SerializationException stating that
    // "Type X in Assembly Y is not marked as serializable."
    public class SerializableExceptionWithCustomProperties : Exception
    {
        private readonly string resourceName;
        private readonly IList<string> validationErrors;

        public SerializableExceptionWithCustomProperties()
        {
        }

        public SerializableExceptionWithCustomProperties(string message) 
            : base(message)
        {
        }

        public SerializableExceptionWithCustomProperties(string message, Exception innerException)
            : base(message, innerException)
        {
        }

        public SerializableExceptionWithCustomProperties(string message, string resourceName, IList<string> validationErrors)
            : base(message)
        {
            this.resourceName = resourceName;
            this.validationErrors = validationErrors;
        }

        public SerializableExceptionWithCustomProperties(string message, string resourceName, IList<string> validationErrors, Exception innerException)
            : base(message, innerException)
        {
            this.resourceName = resourceName;
            this.validationErrors = validationErrors;
        }

        [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter = true)]
        // Constructor should be protected for unsealed classes, private for sealed classes.
        // (The Serializer invokes this constructor through reflection, so it can be private)
        protected SerializableExceptionWithCustomProperties(SerializationInfo info, StreamingContext context)
            : base(info, context)
        {
            this.resourceName = info.GetString("ResourceName");
            this.validationErrors = (IList<string>)info.GetValue("ValidationErrors", typeof(IList<string>));
        }

        public string ResourceName
        {
            get { return this.resourceName; }
        }

        public IList<string> ValidationErrors
        {
            get { return this.validationErrors; }
        }

        [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter = true)]
        public override void GetObjectData(SerializationInfo info, StreamingContext context)
        {
            if (info == null)
            {
                throw new ArgumentNullException("info");
            }

            info.AddValue("ResourceName", this.ResourceName);

            // Note: if "List<T>" isn't serializable you may need to work out another
            //       method of adding your list, this is just for show...
            info.AddValue("ValidationErrors", this.ValidationErrors, typeof(IList<string>));

            // MUST call through to the base class to let it save its own state
            base.GetObjectData(info, context);
        }
    }
}

DerivedSerializableExceptionWithAdditionalCustomProperties.cs:

namespace SerializableExceptions
{
    using System;
    using System.Collections.Generic;
    using System.Runtime.Serialization;
    using System.Security.Permissions;

    [Serializable]
    public sealed class DerivedSerializableExceptionWithAdditionalCustomProperty : SerializableExceptionWithCustomProperties
    {
        private readonly string username;

        public DerivedSerializableExceptionWithAdditionalCustomProperty()
        {
        }

        public DerivedSerializableExceptionWithAdditionalCustomProperty(string message)
            : base(message)
        {
        }

        public DerivedSerializableExceptionWithAdditionalCustomProperty(string message, Exception innerException) 
            : base(message, innerException)
        {
        }

        public DerivedSerializableExceptionWithAdditionalCustomProperty(string message, string username, string resourceName, IList<string> validationErrors) 
            : base(message, resourceName, validationErrors)
        {
            this.username = username;
        }

        public DerivedSerializableExceptionWithAdditionalCustomProperty(string message, string username, string resourceName, IList<string> validationErrors, Exception innerException) 
            : base(message, resourceName, validationErrors, innerException)
        {
            this.username = username;
        }

        [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter = true)]
        // Serialization constructor is private, as this class is sealed
        private DerivedSerializableExceptionWithAdditionalCustomProperty(SerializationInfo info, StreamingContext context)
            : base(info, context)
        {
            this.username = info.GetString("Username");
        }

        public string Username
        {
            get { return this.username; }
        }

        public override void GetObjectData(SerializationInfo info, StreamingContext context)
        {
            if (info == null)
            {
                throw new ArgumentNullException("info");
            }
            info.AddValue("Username", this.username);
            base.GetObjectData(info, context);
        }
    }
}

单元测试

上面定义的三种异常类型的MSTest单元测试。

UnitTests.cs:

namespace SerializableExceptions
{
    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Runtime.Serialization.Formatters.Binary;
    using Microsoft.VisualStudio.TestTools.UnitTesting;

    [TestClass]
    public class UnitTests
    {
        private const string Message = "The widget has unavoidably blooped out.";
        private const string ResourceName = "Resource-A";
        private const string ValidationError1 = "You forgot to set the whizz bang flag.";
        private const string ValidationError2 = "Wally cannot operate in zero gravity.";
        private readonly List<string> validationErrors = new List<string>();
        private const string Username = "Barry";

        public UnitTests()
        {
            validationErrors.Add(ValidationError1);
            validationErrors.Add(ValidationError2);
        }

        [TestMethod]
        public void TestSerializableExceptionWithoutCustomProperties()
        {
            Exception ex =
                new SerializableExceptionWithoutCustomProperties(
                    "Message", new Exception("Inner exception."));

            // Save the full ToString() value, including the exception message and stack trace.
            string exceptionToString = ex.ToString();

            // Round-trip the exception: Serialize and de-serialize with a BinaryFormatter
            BinaryFormatter bf = new BinaryFormatter();
            using (MemoryStream ms = new MemoryStream())
            {
                // "Save" object state
                bf.Serialize(ms, ex);

                // Re-use the same stream for de-serialization
                ms.Seek(0, 0);

                // Replace the original exception with de-serialized one
                ex = (SerializableExceptionWithoutCustomProperties)bf.Deserialize(ms);
            }

            // Double-check that the exception message and stack trace (owned by the base Exception) are preserved
            Assert.AreEqual(exceptionToString, ex.ToString(), "ex.ToString()");
        }

        [TestMethod]
        public void TestSerializableExceptionWithCustomProperties()
        {
            SerializableExceptionWithCustomProperties ex = 
                new SerializableExceptionWithCustomProperties(Message, ResourceName, validationErrors);

            // Sanity check: Make sure custom properties are set before serialization
            Assert.AreEqual(Message, ex.Message, "Message");
            Assert.AreEqual(ResourceName, ex.ResourceName, "ex.ResourceName");
            Assert.AreEqual(2, ex.ValidationErrors.Count, "ex.ValidationErrors.Count");
            Assert.AreEqual(ValidationError1, ex.ValidationErrors[0], "ex.ValidationErrors[0]");
            Assert.AreEqual(ValidationError2, ex.ValidationErrors[1], "ex.ValidationErrors[1]");

            // Save the full ToString() value, including the exception message and stack trace.
            string exceptionToString = ex.ToString();

            // Round-trip the exception: Serialize and de-serialize with a BinaryFormatter
            BinaryFormatter bf = new BinaryFormatter();
            using (MemoryStream ms = new MemoryStream())
            {
                // "Save" object state
                bf.Serialize(ms, ex);

                // Re-use the same stream for de-serialization
                ms.Seek(0, 0);

                // Replace the original exception with de-serialized one
                ex = (SerializableExceptionWithCustomProperties)bf.Deserialize(ms);
            }

            // Make sure custom properties are preserved after serialization
            Assert.AreEqual(Message, ex.Message, "Message");
            Assert.AreEqual(ResourceName, ex.ResourceName, "ex.ResourceName");
            Assert.AreEqual(2, ex.ValidationErrors.Count, "ex.ValidationErrors.Count");
            Assert.AreEqual(ValidationError1, ex.ValidationErrors[0], "ex.ValidationErrors[0]");
            Assert.AreEqual(ValidationError2, ex.ValidationErrors[1], "ex.ValidationErrors[1]");

            // Double-check that the exception message and stack trace (owned by the base Exception) are preserved
            Assert.AreEqual(exceptionToString, ex.ToString(), "ex.ToString()");
        }

        [TestMethod]
        public void TestDerivedSerializableExceptionWithAdditionalCustomProperty()
        {
            DerivedSerializableExceptionWithAdditionalCustomProperty ex = 
                new DerivedSerializableExceptionWithAdditionalCustomProperty(Message, Username, ResourceName, validationErrors);

            // Sanity check: Make sure custom properties are set before serialization
            Assert.AreEqual(Message, ex.Message, "Message");
            Assert.AreEqual(ResourceName, ex.ResourceName, "ex.ResourceName");
            Assert.AreEqual(2, ex.ValidationErrors.Count, "ex.ValidationErrors.Count");
            Assert.AreEqual(ValidationError1, ex.ValidationErrors[0], "ex.ValidationErrors[0]");
            Assert.AreEqual(ValidationError2, ex.ValidationErrors[1], "ex.ValidationErrors[1]");
            Assert.AreEqual(Username, ex.Username);

            // Save the full ToString() value, including the exception message and stack trace.
            string exceptionToString = ex.ToString();

            // Round-trip the exception: Serialize and de-serialize with a BinaryFormatter
            BinaryFormatter bf = new BinaryFormatter();
            using (MemoryStream ms = new MemoryStream())
            {
                // "Save" object state
                bf.Serialize(ms, ex);

                // Re-use the same stream for de-serialization
                ms.Seek(0, 0);

                // Replace the original exception with de-serialized one
                ex = (DerivedSerializableExceptionWithAdditionalCustomProperty)bf.Deserialize(ms);
            }

            // Make sure custom properties are preserved after serialization
            Assert.AreEqual(Message, ex.Message, "Message");
            Assert.AreEqual(ResourceName, ex.ResourceName, "ex.ResourceName");
            Assert.AreEqual(2, ex.ValidationErrors.Count, "ex.ValidationErrors.Count");
            Assert.AreEqual(ValidationError1, ex.ValidationErrors[0], "ex.ValidationErrors[0]");
            Assert.AreEqual(ValidationError2, ex.ValidationErrors[1], "ex.ValidationErrors[1]");
            Assert.AreEqual(Username, ex.Username);

            // Double-check that the exception message and stack trace (owned by the base Exception) are preserved
            Assert.AreEqual(exceptionToString, ex.ToString(), "ex.ToString()");
        }
    }
}
r8uurelv

r8uurelv2#

Exception已经是可序列化的了,但是你需要重写GetObjectData方法来存储你的变量,并提供一个构造函数,当重新水合你的对象时可以调用它。
所以你的例子变成了:

[Serializable]
public class MyException : Exception
{
    private readonly string resourceName;
    private readonly IList<string> validationErrors;

    public MyException(string resourceName, IList<string> validationErrors)
    {
        this.resourceName = resourceName;
        this.validationErrors = validationErrors;
    }

    public string ResourceName
    {
        get { return this.resourceName; }
    }

    public IList<string> ValidationErrors
    {
        get { return this.validationErrors; }
    }

    [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter=true)]
    protected MyException(SerializationInfo info, StreamingContext context) : base (info, context)
    {
        this.resourceName = info.GetString("MyException.ResourceName");
        this.validationErrors = info.GetValue("MyException.ValidationErrors", typeof(IList<string>));
    }

    [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter=true)]
    public override void GetObjectData(SerializationInfo info, StreamingContext context)
    {
        base.GetObjectData(info, context);

        info.AddValue("MyException.ResourceName", this.ResourceName);

        // Note: if "List<T>" isn't serializable you may need to work out another
        //       method of adding your list, this is just for show...
        info.AddValue("MyException.ValidationErrors", this.ValidationErrors, typeof(IList<string>));
    }

}
oxalkeyp

oxalkeyp3#

为了补充上面的正确答案,我发现如果将自定义属性存储在Exception类的Data collection中,就可以避免这种自定义序列化操作。
例如:

[Serializable]
public class JsonReadException : Exception
{
    // ...

    public string JsonFilePath
    {
        get { return Data[@"_jsonFilePath"] as string; }
        private set { Data[@"_jsonFilePath"] = value; }
    }

    public string Json
    {
        get { return Data[@"_json"] as string; }
        private set { Data[@"_json"] = value; }
    }

    // ...
}

可能这在性能方面不如the solution provided by Daniel有效,并且可能只适用于“整数”类型,如字符串和整数等。
不过,这对我来说很容易,也很容易理解。

7gyucuyw

7gyucuyw4#

实现ISerializable,并按照normal pattern执行此操作。
您需要用[Serializable]属性标记类,并添加对该接口的支持,还需要添加隐含的构造函数(在该页面上进行了描述,搜索 * 意味着一个构造函数 *)。您可以在文本下方的代码中看到其实现的示例。

k97glaaz

k97glaaz5#

曾经在MSDN上有一篇来自Eric Gunnerson的优秀文章“The well-tempered exception”,但它似乎已经被删除了。URL是:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dncscol/html/csharp08162001.asp
Aydsman的答案是正确的,更多信息在这里:
http://msdn.microsoft.com/en-us/library/ms229064.aspx
我想不出任何使用非序列化成员的Exception的用例,但是如果你避免在GetObjectData和反序列化构造函数中序列化/反序列化它们,你应该没问题。还要用[NonSerialized]属性来标记它们,这更像是一个文档,而不是其他任何东西,因为您是自己实现序列化的。

xqnpmsa8

xqnpmsa86#

在.NET Core中,.Net 5.0及更高版本不使用Serializable,因为Microsoft遵循BinaryFormatter中的安全威胁实践。
使用存储在数据收集中的示例

siotufzp

siotufzp7#

用[Serializable]标记这个类,尽管我不确定序列化器处理IList成员的效果如何。

编辑

下面的帖子是正确的,因为您的自定义异常具有接受参数的构造函数,所以您必须实现ISerializable。
如果使用默认构造函数并使用getter/setter属性公开两个自定义成员,则只需设置属性即可。

i7uq4tfw

i7uq4tfw8#

我不得不认为,想要序列化一个异常是一个强烈的迹象,表明你正在采取错误的方法。最终目标是什么?如果在两个进程之间传递异常,或者在同一进程的不同运行之间传递异常,那么异常的大多数属性在另一个进程中都是无效的。
在catch()语句中提取所需的状态信息并将其存档可能更有意义。

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