JAVA序列化与反序列化三种格式存取（默认格式、XML格式、JSON格式）

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。

上面两段来源：http://lionheart.iteye.com/blog/139540

 

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

 

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

 

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}}