import java.io.*;
public class Ans {
public static void main(String[] args) throws IOException, ClassNotFoundException {
//test0();
//test1();
//test2();
//test3();
//test4();
test5();
}
static void test0() throws IOException, ClassNotFoundException {
//序列化可以让我们拥有保存对象到文件的能力
//序列化实现Serializable的对象不会调用构造函数，但是要保证可以找到.class文件
class B { //没有实现Serializable的类出现在序列化中会报错
B() {System.out.println("New B");}
B(int i) {System.out.println("New B With I");}
}
class C{
C() {System.out.println("New C");}
}
class A extends C implements Serializable { //如果父类没有实现Serializable，在重新导入时会调用默认构造函数
A(int x,String s,A a) {this.x=x;this.s=s;this.a=a; }
@Override
public String toString() {
return "A{" +
"x=" + x +
", s='" + s + '\'' +
", a=" + a +
'}';
}
//! B b = new B(1);
int x;
String s;
A a;
}
A a = new A(0,"a",null);
a = new A(1,"c",a);
a = new A(2,"d",a);
a = new A(3,"e",a);
a = new A(4,"f",a);
System.out.println(a);
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test"));
oos.writeObject(a);
oos.close();
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test"));
a = (A)ois.readObject();
System.out.println(a);
}
static void test1() throws IOException, ClassNotFoundException {
//如果想控制序列化行为，就需要使用Externalizable然后实现writeExternal和readExternal
class A implements Externalizable {
public A() {System.out.println("New A");} //Externalizable会的调用默认构造器构造对象，然后使用readExternal，所以默认构造器必须是存在的而且是public
A(int x,String s,A a) {this.x=x;code=s;this.a=a; }
public void writeExternal(ObjectOutput oo) throws IOException {
oo.writeInt(x);
oo.writeObject(a);
}
public void readExternal(ObjectInput oi) throws IOException, ClassNotFoundException {
x = oi.readInt();
a = (A) oi.readObject();
code = "no";
}
@Override
public String toString() {
return "A{" +
"x=" + x +
", code='" + code + '\'' +
", a=" + a +
'}';
}
int x;
String code;
A a;
}
A a = new A(0,"a",null);
a = new A(1,"c",a);
a = new A(2,"d",a);
a = new A(3,"e",a);
a = new A(4,"f",a);
System.out.println(a);
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test"));
oos.writeObject(a);
oos.close();
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test"));
a = (A)ois.readObject();
System.out.println(a);
}
static void test2() throws IOException, ClassNotFoundException {
//有些属性不想传输出去，可以使用transient关键字
class A implements Serializable {
A(int x,String s,A a) {this.x=x;code=s;this.a=a; }
@Override
public String toString() {
return "A{" +
"x=" + x +
", code='" + code + '\'' +
", a=" + a +
'}';
}
int x;
transient String code;
A a;
}
A a = new A(0,"a",null);
a = new A(1,"c",a);
a = new A(2,"d",a);
a = new A(3,"e",a);
a = new A(4,"f",a);
System.out.println(a);
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test"));
oos.writeObject(a);
oos.close();
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test"));
a = (A)ois.readObject();
System.out.println(a);
}
static void test3() throws IOException,ClassNotFoundException {
//如果不想使用Externalizable，可以使用Serializable然后添加writeObject,readObject，这里添加的两个两个方法不是继承而来也不是实现接口中的方法，其实只是两个普通的方法，只不过在运行时ObjectInputStream和ObjectOutputStream会通过反射调用他们
class A implements Serializable {
A(int x,String s,A a) {this.x=x;code=s;this.a=a; }
private void writeObject(ObjectOutputStream oos) throws IOException {
oos.writeInt(x);
oos.defaultWriteObject(); //通过这个先进行正常的保存，通过反射来实现
oos.writeObject("tts");
}
private void readObject(ObjectInputStream ois) throws IOException,ClassNotFoundException {
System.out.println(ois.readInt());
ois.defaultReadObject();
String s = (String)ois.readObject();
System.out.println(s+"*");
}
@Override
public String toString() {
return "A{" +
"x=" + x +
", code='" + code + '\'' +
", a=" + a +
'}';
}
int x;
String code;
A a;
}
A a = new A(0,"a",null);
a = new A(1,"c",a);
a = new A(2,"d",a);
a = new A(3,"e",a);
a = new A(4,"f",a);
System.out.println(a);
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test"));
oos.writeObject(a);
oos.close();
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test"));
a = (A)ois.readObject();
System.out.println(a);
}
static void test4() throws IOException,ClassNotFoundException {
class B implements Serializable {B() {System.out.println("New B");}}
class A implements Serializable {
A(int x,String s,A a,B b) {this.x=x;code=s;this.a=a;this.b=b; }
@Override
public String toString() {
return "A{" +
"x=" + x +
", code='" + code + '\'' +
", a=" + a +
", b=" + b +
'}';
}
int x;
String code;
A a;
B b;
}
A a = new A(0,"a",null,new B());
a = new A(1,"c",a,new B());
a = new A(2,"d",a,new B());
a = new A(3,"e",a,new B());
a = new A(4,"f",a,new B());
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test"));
ObjectOutputStream oos2 = new ObjectOutputStream(new FileOutputStream("test2"));
oos.writeObject(a);
oos.writeObject(a);
oos2.writeObject(a);
oos.close();
oos2.close();
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test"));
ObjectInputStream ois2 = new ObjectInputStream(new FileInputStream("test2"));
a = (A)ois.readObject();
A a2 = (A)ois.readObject();
A a3 = (A)ois2.readObject();
System.out.println(a); //同一个对象存入同一个流两次，拿出后的结果只会创建一个实例，而放入不同的流两次，拿出后会创建两个不同的实例
System.out.println(a2);
System.out.println(a3);
}
static void test5() throws IOException,ClassNotFoundException {
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test"));
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test"));
X x = new X();
oos.writeObject(x);
x = (X) ois.readObject();
System.out.println(x); //如果在别的文件下这个x中俄的static属性无法被保存，所以需要编写额外的代码将其存入
}
static void test6() {
//书中还降到了用XML和Preference来实现序列化，但是由于讲的比较少，在这里先不搞了，以后会深入探究，同时这两方法是不限于java语言的
}
}
class X implements Serializable {
@Override
public String toString() {
return String.valueOf(x);
}
static int x = 10;
}
