blocks|key|1527166|text|把数据写到ByteArrayOutputStream而不是FileOutputStream怎么样？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1527167|否则，您可以使用XMLEncoder序列化对象，持久化XML，然后通过XMLDecoder进行反序列化。|1527168|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

How about writing the data to a ByteArrayOutputStream instead of a FileOutputStream?

Otherwise, you could serialize the object using XMLEncoder, persist the XML, then deserialize via XMLDecoder.

blocks|key|1742237|text|将对象持久化为blob怎么样？|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1742238|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.oracle.com/javase/7/docs/api/java/sql/Blob.html^0|7|4|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

How about persisting the object as a <a href="https://docs.oracle.com/javase/7/docs/api/java/sql/Blob.html" rel="nofollow noreferrer">blob</a>

blocks|key|1742252|text|您可以使用UUEncoding|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1742253|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

blocks|key|1527305|text|如果您在数据库中将对象存储为二进制数据，那么您确实应该使用BLOB数据类型。数据库能够更有效地存储数据，您不必担心编码等问题。JDBC提供了根据流创建和检索blobs的方法。如果可以，请使用Java+6，它对JDBC+API做了一些添加，使处理blobs变得非常容易。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1527306|如果您绝对需要将数据存储为字符串，我建议将XStream用于基于XML的存储(比XMLEncoder简单得多)，但是替代的对象表示可能也同样有用(例如JSON)。您的方法取决于为什么您实际上需要以这种方式存储对象。|1527307|entityMap|0|LINK|mutability|MUTABLE|url|http://xstream.codehaus.org/^0|T|4|0|14|A|L|7|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|H|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

If you're storing an object as binary data in the database, then you really should use a <code>BLOB</code> datatype. The database is able to store it more efficiently, and you don't have to worry about encodings and the like. JDBC provides methods for creating and retrieving blobs in terms of streams. Use Java 6 if you can, it made some additions to the JDBC API that make dealing with blobs a whole lot easier.

If you absolutely need to store the data as a String, I would recommend <a href="http://xstream.codehaus.org/" rel="nofollow noreferrer">XStream</a> for XML-based storage (much easier than <code>XMLEncoder</code>), but alternative object representations might be just as useful (e.g. JSON). Your approach depends on why you actually need to store the object in this way.

blocks|key|1527378|text|序列化的流只是一个字节序列(八位字节)。因此，问题是如何将字节序列转换为字符串，然后再转换回来。此外，如果要将其存储在数据库中，则需要使用一组有限的字符代码。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1527379|该问题的明显解决方案是将该字段更改为二进制LOB。如果您想坚持使用字符LOB，那么您将需要以某种方案进行编码，例如base64、十六进制或uu。|1527380|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

The serialised stream is just a sequence of bytes (octets). So the question is how to convert a sequence of bytes to a String, and back again. Further it needs to use a limited set of character codes if it is going to be stored in a database.

The obvious solution to the problem is to change the field to a binary LOB. If you want to stick with a characer LOB, then you'll need to encode in some scheme such as base64, hex or uu.

blocks|key|1527464|text|看一看java.sql.PreparedStatement类，特别是函数|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1527465|http://java.sun.com/javase/6/docs/api/java/sql/PreparedStatement.html#setBinaryStream(int,%2520java.io.InputStream)|offset|length|1527466|然后看一下java.sql.ResultSet类，特别是函数|1527467|http://java.sun.com/javase/6/docs/api/java/sql/ResultSet.html#getBinaryStream(int)|1527468|请记住，如果要将对象序列化到数据库中，然后在新版本的代码中更改该对象，则反序列化过程很容易失败，因为对象的签名已更改。我曾经在存储序列化的自定义首选项，然后对首选项定义进行更改时犯下了这个错误。突然之间，我无法读取任何以前序列化的信息。|1527469|您最好在表中编写笨重的每个属性列，并以这种方式组合和分解对象，以避免对象版本和反序列化出现此问题。或者将属性写入某种哈希表中，如java.util.Properties对象，然后序列化极不可能更改的属性对象。|1527470|entityMap|0|LINK|mutability|MUTABLE|url|http://java.sun.com/javase/6/docs/api/java/sql/PreparedStatement.html#setBinaryStream(int,%2520java.io.InputStream)|1^0|0|0|35|0|0|0|0|2A|1|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@$D|Y|E|Z|1|10]]|A|$]]|$1|F|3|G|5|6|7|11|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|12|8|@]|9|@$D|13|E|14|1|15]]|A|$]]|$1|J|3|K|5|6|7|16|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|17|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|O|$P|$5|Q|R|S|A|$T|U]]|V|$5|Q|R|S|A|$T|I]]]]

Take a look at the java.sql.PreparedStatement class, specifically the function

<a href="http://java.sun.com/javase/6/docs/api/java/sql/PreparedStatement.html#setBinaryStream(int,%20java.io.InputStream)" rel="nofollow noreferrer">http://java.sun.com/javase/6/docs/api/java/sql/PreparedStatement.html#setBinaryStream(int,%20java.io.InputStream)</a>

Then take a look at the java.sql.ResultSet class, specifically the function

<a href="http://java.sun.com/javase/6/docs/api/java/sql/ResultSet.html#getBinaryStream(int)" rel="nofollow noreferrer">http://java.sun.com/javase/6/docs/api/java/sql/ResultSet.html#getBinaryStream(int)</a>

Keep in mind that if you are serializing an object into a database, and then you change the object in your code in a new version, the deserialization process can easily fail because your object's signature changed. I once made this mistake with storing a custom Preferences serialized and then making a change to the Preferences definition. Suddenly I couldn't read any of the previously serialized information.

You might be better off writing clunky per property columns in a table and composing and decomposing the object in this manner instead, to avoid this issue with object versions and deserialization. Or writing the properties into a hashmap of some sort, like a java.util.Properties object, and then serializing the properties object which is extremely unlikely to change.

blocks|key|1742581|text|您可以使用内置的类sun.misc.Base64Decoder和sun.misc.Base64Encoder将序列化的二进制数据转换为字符串。你不需要额外的类，因为它是内置的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1742582|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You can use the build in classes sun.misc.Base64Decoder and sun.misc.Base64Encoder to convert the binary data of the serialize to a string. You das not need additional classes because it are build in.

blocks|key|1527576|text|Java8方法，将对象从字符串转换为字符串，灵感来自OscarRyz的answer。对于反/编码，需要并使用java.util.Base64。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1527577|import+java.io.ByteArrayInputStream;
import+java.io.ByteArrayOutputStream;
import+java.io.IOException;
import+java.io.ObjectInputStream;
import+java.io.ObjectOutputStream;
import+java.io.Serializable;
import+java.util.Base64;
import+java.util.Optional;

final+class+ObjectHelper+{

++private+ObjectHelper()+{}

++static+Optional<String>+convertToString(final+Serializable+object)+{
++++try+(final+ByteArrayOutputStream+baos+=+new+ByteArrayOutputStream();
++++++ObjectOutputStream+oos+=+new+ObjectOutputStream(baos))+{
++++++oos.writeObject(object);
++++++return+Optional.of(Base64.getEncoder().encodeToString(baos.toByteArray()));
++++}+catch+(final+IOException+e)+{
++++++e.printStackTrace();
++++++return+Optional.empty();
++++}
++}

++static+<T+extends+Serializable>+Optional<T>+convertFrom(final+String+objectAsString)+{
++++final+byte[]+data+=+Base64.getDecoder().decode(objectAsString);
++++try+(final+ObjectInputStream+ois+=+new+ObjectInputStream(new+ByteArrayInputStream(data)))+{
++++++return+Optional.of((T)+ois.readObject());
++++}+catch+(final+IOException+%7C+ClassNotFoundException+e)+{
++++++e.printStackTrace();
++++++return+Optional.empty();
++++}
++}
}|code-block|syntax|javascript|1527578|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/134918/1645517|1|https://docs.oracle.com/javase/8/docs/api/java/util/Base64.html^0|Q|8|0|1I|G|1|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]|$A|W|B|X|1|Y]]|C|$]]|$1|D|3|E|5|F|7|Z|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|10|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]|Q|$5|L|M|N|C|$O|R]]]]

Java8 approach, converting Object from/to String, inspired by answer from <a href="https://stackoverflow.com/a/134918/1645517">OscarRyz</a>. For de-/encoding, <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Base64.html" rel="nofollow noreferrer" title="java.util.Base64">java.util.Base64</a> is required and used.

<pre><code>import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Base64;
import java.util.Optional;

final class ObjectHelper {

 private ObjectHelper() {}

 static Optional&lt;String&gt; convertToString(final Serializable object) {
 try (final ByteArrayOutputStream baos = new ByteArrayOutputStream();
 ObjectOutputStream oos = new ObjectOutputStream(baos)) {
 oos.writeObject(object);
 return Optional.of(Base64.getEncoder().encodeToString(baos.toByteArray()));
 } catch (final IOException e) {
 e.printStackTrace();
 return Optional.empty();
 }
 }

 static &lt;T extends Serializable&gt; Optional&lt;T&gt; convertFrom(final String objectAsString) {
 final byte[] data = Base64.getDecoder().decode(objectAsString);
 try (final ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(data))) {
 return Optional.of((T) ois.readObject());
 } catch (final IOException | ClassNotFoundException e) {
 e.printStackTrace();
 return Optional.empty();
 }
 }
}
</code></pre>

blocks|key|1742657|text|简单的解决方案，对我很有效|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1742658|public+static+byte[]+serialize(Object+obj)+throws+IOException+{
++++ByteArrayOutputStream+out+=+new+ByteArrayOutputStream();
++++ObjectOutputStream+os+=+new+ObjectOutputStream(out);
++++os.writeObject(obj);
++++return+out.toByteArray();
}|code-block|syntax|javascript|1742659|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Simple Solution,worked for me

<pre><code>public static byte[] serialize(Object obj) throws IOException {
 ByteArrayOutputStream out = new ByteArrayOutputStream();
 ObjectOutputStream os = new ObjectOutputStream(out);
 os.writeObject(obj);
 return out.toByteArray();
}
</code></pre>

I am able to serialize an object into a file and then restore it again as is shown in the next code snippet. I would like to serialize the object into a string and store into a database instead. Can anyone help me?

<pre><code>LinkedList&lt;Diff_match_patch.Patch&gt; patches = // whatever...
FileOutputStream fileStream = new FileOutputStream("foo.ser");
ObjectOutputStream os = new ObjectOutputStream(fileStream);
os.writeObject(patches1);
os.close();

FileInputStream fileInputStream = new FileInputStream("foo.ser");
ObjectInputStream oInputStream = new ObjectInputStream(fileInputStream);
Object one = oInputStream.readObject();
LinkedList&lt;Diff_match_patch.Patch&gt; patches3 = (LinkedList&lt;Diff_match_patch.Patch&gt;) one;
os.close();
</code></pre>

How to serialize an object into a string

我能够将一个对象序列化为一个文件，然后再次恢复它，如下面的代码片段所示。我想将对象序列化为字符串并存储到数据库中。有谁可以帮我？LinkedList<Diff_match_patch.Patch> patches = // whatever...FileOutputStream fileStream = new Fil...

问如何将对象序列化为字符串
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