什么是序列化
Java中的序列化（serialization）机制能够将一个实例对象的状态信息写入到一个字节流中，使其可以通过socket进行传输、或者持久化存储到数据库或文件系统中；然后在需要的时候，可以根据字节流中的信息来重构一个相同的对象。序列化机制在Java中有着广泛的应用，EJB、RMI等技术都是以此为基础的。
正确使用序列化机制
一般而言，要使得一个类可以序列化，只需简单实现java.io.Serializable接口即可（还要实现无参数的构造方法）。该接口是一个标记式接口，它本身不包含任何内容，实现了该接口则表示这个类准备支持序列化的功能。如下例定义了类Person，并声明其可以序列化。
public class Person implements Serializable {
private static final long serialVersionUID = 1L;private String name;;private int age;public Person(){}public Person(String str,int n){System.out.println(“Inside Person’s Constructor”);name = str;age = n;}public String getName() {return name;}public int getAge() {return age;}}
下面为三种格式转换的代码：
1、默认格式
public class SerializeToFlatFile {public static void main(String[] args) {SerializeToFlatFile ser = new SerializeToFlatFile();ser.savePerson();ser.restorePerson();}public void savePerson(){Person myPerson = new Person(“Jay”, 24);try{FileOutputStream fos = new FileOutputStream(“E:\\person.txt”);ObjectOutputStream oos = new ObjectOutputStream(fos);System.out.println(“Person–Jay,24—Written”);oos.writeObject(myPerson);oos.flush();oos.close();}catch(Exception e){e.printStackTrace();}}@SuppressWarnings(“resource”)public void restorePerson(){try{FileInputStream fls = new FileInputStream(“E:\\person.txt”);ObjectInputStream ois = new ObjectInputStream(fls);Person myPerson = (Person)ois.readObject();System.out.println(“\n———————\n”);System.out.println(“Person –read:”);System.out.println(“Name is:”+myPerson.getName());System.out.println(“Age is :”+myPerson.getAge());}catch(Exception e){e.printStackTrace();}}}
输出结果：? sr test.serializable.Person I ageL namet Ljava/lang/String;xp t Jay
2、XML格式
//参考:public class SerializeXML {
public static void main(String[] args) {SerializeXML ser = new SerializeXML();ser.serializeToXml();ser.deSerializeFromXml();}public void serializeToXml(){Person[] myPersons = new Person[2];myPersons[0] = new Person(“Jay”, 24);myPersons[1] = new Person(“Tom”, 23);XStream xStream = new XStream();xStream.alias(“Person”, Person.class);try{FileOutputStream foStream = new FileOutputStream(“E:\\persons.xml”);xStream.toXML(myPersons,foStream);}catch(Exception e){e.printStackTrace();}}public void deSerializeFromXml(){XStream xStream = new XStream();xStream.alias(“Person”, Person.class);Person[] myPersons = null;try{FileInputStream flStream = new FileInputStream(“E:\\persons.xml”);myPersons = (Person[])xStream.fromXML(flStream);if(myPersons!=null){for(Person person:myPersons){System.out.println(person.getName());System.out.println(person.getAge());}}}catch(Exception e){e.printStackTrace();}}}
输出结果：
<Person-array> <Person> <name>Jay</name> <age>24</age> </Person> <Person> <name>Tom</name> <age>23</age> </Person></Person-array>
3、JSON格式
//参考:public class SerializeJSON {
public static void main(String[] args) {SerializeJSON serializeJSON = new SerializeJSON();serializeJSON.writeJSON();serializeJSON.readJSON();}
public void writeJSON(){XStream xStream = new XStream(new JettisonMappedXmlDriver());Person person = new Person(“geniushehe”, 16);try {FileOutputStream fos = new FileOutputStream(“E:\\json.js”);xStream.setMode(XStream.NO_REFERENCES);xStream.alias(“Person”, Person.class);xStream.toXML(person, fos);} catch (FileNotFoundException e) {e.printStackTrace();}}public void readJSON(){XStream xStream = new XStream(new JettisonMappedXmlDriver());Person person = null;try {FileInputStream fis = new FileInputStream(“E:\\json.js”);xStream.setMode(XStream.NO_REFERENCES);xStream.alias(“Person”, Person.class);person = (Person)xStream.fromXML(fis);System.out.println(person.getName());System.out.println(person.getAge());} catch (FileNotFoundException e) {e.printStackTrace();}}}
输出结果：
{“Person”:{“name”:”geniushehe”,”age”:16}}
我也相信爱可以排除万难;只是，万难之后，又有万难。这是我更相信的。
