最好的方法是使用Apache Commons Lang中的SerializationUtils。

序列化:

byte[] data = SerializationUtils.serialize(yourObject);

反序列化:

YourObject yourObject = SerializationUtils.deserialize(data)

如前所述，这需要Commons Lang库。它可以使用Gradle导入:

compile 'org.apache.commons:commons-lang3:3.5'

Maven:

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.5</version>
</dependency>

Jar文件

这里提到了更多的方法

或者，可以导入整个集合。参考这个连结

如果你使用Java >= 7，你可以使用try和资源改进接受的解决方案:

private byte[] convertToBytes(Object object) throws IOException {
    try (ByteArrayOutputStream bos = new ByteArrayOutputStream();
         ObjectOutputStream out = new ObjectOutputStream(bos)) {
        out.writeObject(object);
        return bos.toByteArray();
    } 
}

反过来说:

private Object convertFromBytes(byte[] bytes) throws IOException, ClassNotFoundException {
    try (ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
         ObjectInputStream in = new ObjectInputStream(bis)) {
        return in.readObject();
    } 
}

这只是一个被接受的答案的优化代码形式，以防有人想在生产中使用它:

    public static void byteArrayOps() throws IOException, ClassNotFoundException{

    String str="123";
     byte[] yourBytes = null;

    // Convert to byte[]

    try(ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutputStream out =  new ObjectOutputStream(bos);) {


      out.writeObject(str);
      out.flush();
      yourBytes = bos.toByteArray();

    } finally {

    }

    // convert back to Object

    try(ByteArrayInputStream bis = new ByteArrayInputStream(yourBytes);
            ObjectInput in = new ObjectInputStream(bis);) {

      Object o = in.readObject(); 

    } finally {

    }




}

我也推荐使用SerializationUtils工具。我想对@Abilash的错误评论做一个调整。SerializationUtils.serialize()方法不限制为1024字节，这与这里的另一个答案相反。

public static byte[] serialize(Object object) {
    if (object == null) {
        return null;
    }
    ByteArrayOutputStream baos = new ByteArrayOutputStream(1024);
    try {
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        oos.writeObject(object);
        oos.flush();
    }
    catch (IOException ex) {
        throw new IllegalArgumentException("Failed to serialize object of type: " + object.getClass(), ex);
    }
    return baos.toByteArray();
}

乍一看，您可能认为新的ByteArrayOutputStream(1024)只允许固定的大小。但是如果你仔细观察ByteArrayOutputStream，你会发现流在必要时还会增长:

该类实现了一个输出流，其中数据为 写入字节数组。缓冲区自动作为数据增长 被写入。 可以使用toByteArray()和 toString ()。

Java 8+的代码示例:

public class Person implements Serializable {

private String lastName;
private String firstName;

public Person() {
}

public Person(String firstName, String lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
}

public void setFirstName(String firstName) {
    this.firstName = firstName;
}

public String getFirstName() {
    return firstName;
}

public String getLastName() {
    return lastName;
}

public void setLastName(String lastName) {
    this.lastName = lastName;
}

@Override
public String toString() {
    return "firstName: " + firstName + ", lastName: " + lastName;
}
}


public interface PersonMarshaller {
default Person fromStream(InputStream inputStream) {
    try (ObjectInputStream objectInputStream = new ObjectInputStream(inputStream)) {
        Person person= (Person) objectInputStream.readObject();
        return person;
    } catch (IOException | ClassNotFoundException e) {
        System.err.println(e.getMessage());
        return null;
    }
}

default OutputStream toStream(Person person) {
    try (OutputStream outputStream = new ByteArrayOutputStream()) {
        ObjectOutput objectOutput = new ObjectOutputStream(outputStream);
        objectOutput.writeObject(person);
        objectOutput.flush();
        return outputStream;
    } catch (IOException e) {
        System.err.println(e.getMessage());
        return null;
    }

}

}

Spring框架org.springframework.util.SerializationUtils

byte[] data = SerializationUtils.serialize(obj);