问题描述
下面的fun()函数对data进行解压缩并反序列化voidfun(){byte[]data=getData();byte[]data2=myDecompress(data);//调用myDecompress函数解压缩BinaryFormatterbf=newBinaryFormatter();MemoryStreamms=newMemoryStream(data2);objectsurrogate=bf.Deserialize(ms);//反序列化}(1)privatebyte[]myDecompress(byte[]data)//解压缩函数一，这段代码没问题{MemoryStreamms=newMemoryStream(data);GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress,true);byte[]buffer=newbyte[4096];MemoryStreamoutput=newMemoryStream();intread=-1;read=zipStream.Read(buffer,0,buffer.Length);while(read>0){output.Write(buffer,0,read);read=zipStream.Read(buffer,0,buffer.Length);}zipStream.Close();ms.Close();returnoutput.ToArray();}(2)privatebyte[]myDecompress2(byte[]data)//解压缩函数二，这段代码被调用后会产生异常{MemoryStreamms=newMemoryStream();GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress,true);byte[]buffer=newbyte[data.Length];//如果数组data的长度太长，是不是这句写的不合理呢？zipStream.Read(buffer,0,data.Length);returnbuffer;}本人觉得第2段代码直接返回buffer跟第一段的代码效果一样，但这样当调用fun()函数中的objectsurrogate=bf.Deserialize(ms);时会引发SerializationException异常:EndofStreamencounteredbeforeparsingwascompleted.然后在函数myDecompress2中byte[]buffer=newbyte[data.Length];//如果数组data的长度太长，是不是这句写的不合理呢？请教各位，谢谢！
解决方案
解决方案二：
(2)privatebyte[]myDecompress2(byte[]data)//解压缩函数二，这段代码被调用后会产生异常{MemoryStreamms=newMemoryStream();GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress,true);byte[]buffer=newbyte[data.Length];//如果数组data的长度太长，是不是这句写的不合理呢？zipStream.Read(buffer,0,data.Length);returnbuffer;}问题太大了把MemoryStreamms=newMemoryStream();//空~~byte[]buffer=newbyte[data.Length];解压后的大小不是这个你返回了一个空~~然后去反序列化空~~
解决方案三：
2)privatebyte[]myDecompress2(byte[]data)//解压缩函数二，这段代码被调用后会产生异常{MemoryStreamms=newMemoryStream();GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress,true);byte[]buffer=newbyte[data.Length];//如果数组data的长度太长，是不是这句写的不合理呢？zipStream.Read(buffer,0,data.Length);returnbuffer.ToArray();}
解决方案四：
privatebyte[]myDecompress2(byte[]data)//解压缩函数二，这段代码被调用后会产生异常{MemoryStreamms=newMemoryStream();GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress,true);byte[]buffer=newbyte[data.Length];//如果数组data的长度太长，是不是这句写的不合理呢？zipStream.Read(buffer,0,data.Length);returnbuffer.ToArray();}
解决方案五：
不要意思把函数myDecompress2(byte[]data)里第一句更正如下：MemoryStreamms=newMemoryStream(data);
解决方案六：
回3楼没有buffer.ToArray()这个方法
解决方案七：
引用5楼yangxinglouis的回复:
回3楼没有buffer.ToArray()这个方法
byte[]buffer是一个数组,怎么会没有.ToArray()方法?你测试过了?
解决方案八：
对呀测试过了没有这个方法
解决方案九：
问题应该是处在buffer数组的长度上buffer数组的长度定义应该是取解压缩后的字符流长度byte[]buffer=newbyte[data.Length];==>byte[]buffer=newbyte[zipStream.Length];
解决方案十：
读取的方法同样也要修改，希望能对你有所帮助
解决方案十一：
回楼上我把方法改称这样子：privatebyte[]myDecompress2(byte[]data)//解压缩函数二，这段代码被调用后会产生异常{MemoryStreamms=newMemoryStream();GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress,true);byte[]buffer=newbyte[zipStream.Length];zipStream.Read(buffer,0,Convert.ToInt32(zipStream.Length));returnbuffer;}执行到此句byte[]buffer=newbyte[zipStream.Length];时抛出NotSupportedExceptionThisoperationisnotsupported.
解决方案十二：
对于方法二抛出的异常更详细的信息如下：<ExceptionType>System.Runtime.Serialization.SerializationException,mscorlib,Version=2.0.0.0,Culture=neutral,PublicKeyToken=b77a5c561934e089</ExceptionType><Message>Binarystream'0'doesnotcontainavalidBinaryHeader.Possiblecausesareinvalidstreamorobjectversionchangebetweenserializationanddeserialization.</Message>
解决方案十三：
下面给出测试代码(windows应用程序)希望通过大家的努力能知道为什么！usingSystem;usingSystem.Collections.Generic;usingSystem.ComponentModel;usingSystem.Data;usingSystem.Drawing;usingSystem.Text;usingSystem.Windows.Forms;usingSystem.Data.SqlClient;usingSystem.IO;usingSystem.IO.Compression;usingSystem.Runtime.Serialization.Formatters.Binary;namespaceDataSetApp11{publicpartialclassForm1:Form{publicForm1(){InitializeComponent();}privatevoidbutton1_Click(objectsender,EventArgse){stringconnStr=@"server=WT-SH-GWZ172XSQLEXPRESS;database=test;trusted_connection=true";stringsql="select*frommyUser";DataSetds=newDataSet();using(SqlConnectionconn=newSqlConnection(connStr)){using(SqlDataAdapterda=newSqlDataAdapter(sql,conn)){da.Fill(ds);byte[]data=serializeAndCompressDataSet(ds);//byte[]buffer=myDecompress2(data);//会产生异常byte[]buffer=myDecompress(data);//没问题BinaryFormatterbf=newBinaryFormatter();MemoryStreamms=newMemoryStream(buffer);DataSetds2=bf.Deserialize(ms)asDataSet;ms.Close();this.dataGridView1.DataSource=ds2.Tables[0];}}}privatebyte[]myDecompress2(byte[]data)//解压缩函数二，这段代码被调用后会产生异常{MemoryStreamms=newMemoryStream();GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress,true);byte[]buffer=newbyte[data.Length];//如果数组data的长度太长，是不是这句写的不合理呢？zipStream.Read(buffer,0,Convert.ToInt32(data.Length));returnbuffer;}privatebyte[]myDecompress(byte[]data)//解压缩函数一，这段代码没问题{MemoryStreamms=newMemoryStream(data);GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress,true);byte[]buffer=newbyte[4096];MemoryStreamoutput=newMemoryStream();intread=-1;read=zipStream.Read(buffer,0,buffer.Length);while(read>0){output.Write(buffer,0,read);read=zipStream.Read(buffer,0,buffer.Length);}zipStream.Close();ms.Close();returnoutput.ToArray();}privatebyte[]serializeAndCompressDataSet(DataSetds)//序列化并压缩DataSet{MemoryStreamms=newMemoryStream();BinaryFormatterbf=newBinaryFormatter();bf.Serialize(ms,ds);byte[]data=ms.ToArray();ms.Close();MemoryStreamoutput=newMemoryStream();GZipStreamzipStream=newGZipStream(output,CompressionMode.Compress,true);zipStream.Write(data,0,data.Length);zipStream.Close();output.Close();returnoutput.ToArray();}}}
解决方案十四：
zipStream.Length==》zipStream.BaseStream.Length原因就是buffer数组的长度定义应该是取解压缩后的字符流长度
解决方案十五：
另外MemoryStreamms=newMemoryStream();=>MemoryStreamms=newMemoryStream(data);这个上面有人已经说了
解决方案：
另外如果压缩的字符流比较长zipStream.Read(buffer,0,Convert.ToInt32(zipStream.BaseStream.Length));直接转换成int并不合适，这里只是一个例子，你需要拆分为多个byte数组处理
解决方案：
privatebyte[]myDecompress2(byte[]data){MemoryStreamms=newMemoryStream(data);GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress,true);byte[]buffer=newbyte[zipStream.BaseStream.Length];zipStream.Read(buffer,0,Convert.ToInt32(zipStream.BaseStream.Length));returnbuffer;}请问楼上如果用这种方法是不是读一次就有了呢？但上面的代码还是会有异常。我检查了发现byte[]buffer=myDecompress(data);跟byte[]buffer=myDecompress2(data);buffer的维数是不同的，myDecompress2的小
解决方案：
zipStream.Read(buffer,0,Convert.ToInt32(zipStream.BaseStream.Length));要读多次的因为Read方法的参数是Int，而byte数组的Length是long。可以把byte数组拆成N个长度为2048的数组，最后Contact就好
解决方案：
给你贴下完整的例子源代码吧usingSystem;usingSystem.IO;usingSystem.IO.Compression;publicclassGZipTest{privateconstintbuffer_size=100;publicstaticintReadAllBytesFromStream(Streamstream,byte[]buffer){//Usethismethodisusedtoreadallbytesfromastream.intoffset=0;inttotalCount=0;while(true){intbytesRead=stream.Read(buffer,offset,buffer_size);if(bytesRead==0){break;}offset+=bytesRead;totalCount+=bytesRead;}returntotalCount;}publicstaticboolCompareData(byte[]buf1,intlen1,byte[]buf2,intlen2){//Usethismethodtocomparedatafromtwodifferentbuffers.if(len1!=len2){Console.WriteLine("Numberofbytesintwobufferaredifferent{0}:{1}",len1,len2);returnfalse;}for(inti=0;i<len1;i++){if(buf1[i]!=buf2[i]){Console.WriteLine("byte{0}isdifferent{1}|{2}",i,buf1[i],buf2[i]);returnfalse;}}Console.WriteLine("Allbytescompare.");returntrue;}publicstaticvoidGZipCompressDecompress(stringfilename){Console.WriteLine("Testcompressionanddecompressiononfile{0}",filename);FileStreaminfile;try{//OpenthefileasaFileStreamobject.infile=newFileStream(filename,FileMode.Open,FileAccess.Read,FileShare.Read);byte[]buffer=newbyte[infile.Length];//Readthefiletoensureitisreadable.intcount=infile.Read(buffer,0,buffer.Length);if(count!=buffer.Length){infile.Close();Console.WriteLine("TestFailed:Unabletoreaddatafromfile");return;}infile.Close();MemoryStreamms=newMemoryStream();//Usethenewlycreatedmemorystreamforthecompresseddata.GZipStreamcompressedzipStream=newGZipStream(ms,CompressionMode.Compress,true);Console.WriteLine("Compression");compressedzipStream.Write(buffer,0,buffer.Length);//Closethestream.compressedzipStream.Close();Console.WriteLine("Originalsize:{0},Compressedsize:{1}",buffer.Length,ms.Length);//Resetthememorystreampositiontobegindecompression.ms.Position=0;GZipStreamzipStream=newGZipStream(ms,CompressionMode.Decompress);Console.WriteLine("Decompression");byte[]decompressedBuffer=newbyte[buffer.Length+buffer_size];//UsetheReadAllBytesFromStreamtoreadthestream.inttotalCount=GZipTest.ReadAllBytesFromStream(zipStream,decompressedBuffer);Console.WriteLine("Decompressed{0}bytes",totalCount);if(!GZipTest.CompareData(buffer,buffer.Length,decompressedBuffer,totalCount)){Console.WriteLine("Error.Thetwobuffersdidnotcompare.");}zipStream.Close();}//endtrycatch(InvalidDataException){Console.WriteLine("Error:Thefilebeingreadcontainsinvaliddata.");}catch(FileNotFoundException){Console.WriteLine("Error:Thefilespecifiedwasnotfound.");}catch(ArgumentException){Console.WriteLine("Error:pathisazero-lengthstring,containsonlywhitespace,orcontainsoneormoreinvalidcharacters");}catch(PathTooLongException){Console.WriteLine("Error:Thespecifiedpath,filename,orbothexceedthesystem-definedmaximumlength.Forexample,onWindows-basedplatforms,pathsmustbelessthan248characters,andfilenamesmustbelessthan260characters.");}catch(DirectoryNotFoundException){Console.WriteLine("Error:Thespecifiedpathisinvalid,suchasbeingonanunmappeddrive.");}catch(IOException){Console.WriteLine("Error:AnI/Oerroroccurredwhileopeningthefile.");}catch(UnauthorizedAccessException){Console.WriteLine("Error:pathspecifiedafilethatisread-only,thepathisadirectory,orcallerdoesnothavetherequiredpermissions.");}catch(IndexOutOfRangeException){Console.WriteLine("Error:YoumustprovideparametersforMyGZIP.");}}publicstaticvoidMain(string[]args){stringusageText="Usage:MYGZIP<inputfilename>";//Ifnofilenameisspecified,writeusagetext.if(args.Length==0){Console.WriteLine(usageText);}else{if(File.Exists(args[0]))GZipCompressDecompress(args[0]);}}}
解决方案：
1，压缩前长度和压缩后长度要分清2，Write和Read要分清