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2010-06-01T05:20:03Z

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в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== Create a serialized output file. ==



<source lang="java">
import java.io.FileOutputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.io.Serializable;
public class MainClass {
// Throw exceptions to console:
public static void main(String[] args) throws Exception {
ObjectOutput out = new ObjectOutputStream(new FileOutputStream("X.file"));
MyClass zorcon = new MyClass();
out.writeObject(zorcon);
}
}
// A serializable class.
class MyClass implements Serializable {
}</source>



== Create ObjectOutputStream out of FileOutputStream ==



<source lang="java">
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Date;
public class ObjectWriter {
public static void main(String[] arguments) {
Message mess = new Message();
String author = "London";
String recipient = "G, B";
String[] letter = { "Merry Christmas." };
Date now = new Date();
mess.writeMessage(author, recipient, now, letter);
try {
FileOutputStream fo = new FileOutputStream("Message.obj");
ObjectOutputStream oo = new ObjectOutputStream(fo);
oo.writeObject(mess);
oo.close();
System.out.println("Object created successfully.");
} catch (IOException e) {
System.out.println("Error - " + e.toString());
}
}
}
class Message implements Serializable {
int lineCount;
String from, to;
Date when;
String[] text;
void writeMessage(String inFrom, String inTo, Date inWhen, String[] inText) {
text = new String[inText.length];
for (int i = 0; i < inText.length; i++)
text[i] = inText[i];
lineCount = inText.length;
to = inTo;
from = inFrom;
when = inWhen;
}
}</source>



== illustrates serialization and deserialization ==



<source lang="java">
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
class shutdown {
public static void main(String[] args) throws ClassNotFoundException, IOException {
FileOutputStream fos = new FileOutputStream("objects.tmp");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject("asdf");
oos.flush();
fos.close();

FileInputStream fis = new FileInputStream ("objects.tmp");
ObjectInputStream ois = new ObjectInputStream (fis);
String t = (String) ois.readObject ();
fis.close ();

}
}</source>



== Object IO ==



<source lang="java">
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Date;
public class ObjectIOApp {
public static void main(String args[]) throws IOException, ClassNotFoundException {
File file = new File("test.txt");
FileOutputStream outFile = new FileOutputStream(file);
ObjectOutputStream outStream = new ObjectOutputStream(outFile);
TestClass1 t1 = new TestClass1(true, 9, "A", 0.0001, "java");
TestClass2 t2 = new TestClass2();
String t3 = "This is a test.";
Date t4 = new Date();
outStream.writeObject(t1);
outStream.writeObject(t2);
outStream.writeObject(t3);
outStream.writeObject(t4);
outStream.close();
outFile.close();
FileInputStream inFile = new FileInputStream(file);
ObjectInputStream inStream = new ObjectInputStream(inFile);
System.out.println(inStream.readObject());
System.out.println(inStream.readObject());
System.out.println(inStream.readObject());
System.out.println(inStream.readObject());
inStream.close();
inFile.close();
file.delete();
}
}
class TestClass1 implements Serializable {
boolean b;
int i;
char c;
double d;
String s;
TestClass1(boolean b, int i, char c, double d, String s) {
this.b = b;
this.i = i;
this.c = c;
this.d = d;
this.s = s;
}
public String toString() {
String r = String.valueOf(b) + " ";
r += String.valueOf(i) + " ";
r += String.valueOf(c) + " ";
r += String.valueOf(d) + " ";
r += String.valueOf(s);
return r;
}
}
class TestClass2 implements Serializable {
int i;
TestClass1 tc1;
TestClass1 tc2;
TestClass2() {
i = 0;
tc1 = new TestClass1(true, 2, "j", 1.234, "Java");
tc2 = new TestClass1(false, 7, "J", 2.468, "JAVA");
}
public String toString() {
String r = String.valueOf(i) + " ";
r += tc1.toString() + " ";
r += tc2.toString();
return r;
}
}</source>



== Reading Basic Data From an Object Stream ==



<source lang="java">
import java.awt.Polygon;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
public class MainClass {
public static void main(String[] args) {
int[] x = new int[] { 1, 2, 3 };
int[] y = new int[] { 4, 5, 6 };
Polygon polygon = new Polygon(x, y, x.length);
try {
ObjectOutputStream objectOut = new ObjectOutputStream(new BufferedOutputStream(
new FileOutputStream("C:/Polygons.bin")));
objectOut.writeObject(polygon);
objectOut.close();
} catch (IOException e) {
e.printStackTrace(System.err);
}
try {
ObjectInputStream objectIn = new ObjectInputStream(new BufferedInputStream(
new FileInputStream("C:/Polygons.bin")));
Polygon theLine = (Polygon) objectIn.readObject();
System.out.println(theLine);
objectIn.close();
} catch (Exception e) {
e.printStackTrace(System.err);
}
}
}</source>



== Serializing an Object (JButton) ==



<source lang="java">
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import javax.swing.JButton;
public class Main {
public static void main(String[] argv) throws Exception {
Object object = new JButton("push me");
ObjectOutput out = new ObjectOutputStream(new FileOutputStream("filename.ser"));
out.writeObject(object);
out.close();
// Serialize to a byte array
ByteArrayOutputStream bos = new ByteArrayOutputStream();
out = new ObjectOutputStream(bos);
out.writeObject(object);
out.close();
// Get the bytes of the serialized object
byte[] buf = bos.toByteArray();
System.out.println(new String(buf));
}
}</source>



== Try to recover a serialized file without the class of object that"s stored in that file ==



<source lang="java">
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.io.Serializable;
public class MainClass {
public static void main(String[] args) throws Exception {
ObjectOutput out = new ObjectOutputStream(new FileOutputStream("X.file"));
MyClass zorcon = new MyClass();
out.writeObject(zorcon);

ObjectInputStream in = new ObjectInputStream(new FileInputStream(new File("X.file")));
Object mystery = in.readObject();
System.out.println(mystery.getClass());

}
}
// A serializable class.
class MyClass implements Serializable {
}</source>



== Writing objects to file with ObjectOutputStream ==



<source lang="java">
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
class Person implements Serializable {
private String firstName;
private String lastName;
private int age;
public Person() {
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String toString() {
StringBuffer buffer = new StringBuffer();
buffer.append(firstName);
buffer.append("\n");
buffer.append(lastName);
buffer.append("\n");
buffer.append(age);
buffer.append("\n");
return buffer.toString();
}
}
public class Main {
public static void main(String[] args) throws Exception {
ObjectOutputStream outputStream = null;
outputStream = new ObjectOutputStream(new FileOutputStream("yourFile.dat"));
Person person = new Person();
person.setFirstName("A");
person.setLastName("B");
person.setAge(38);
outputStream.writeObject(person);
person = new Person();
person.setFirstName("C");
person.setLastName("D");
person.setAge(22);
outputStream.writeObject(person);
}
}</source>

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Admin: 1 версия

в 17:44, 31 мая 2010