Read / Write data in a file for transient field using ObjectOutputStream

Using ObjectOutputStream class & transient keyword:

1. import java.io.File;
2. import java.io.FileOutputStream;
3. import java.io.ObjectOutputStream;
4. import java.io.Serializable;
5. 
   
6. class Employee implements Serializable {
7. 
   
8. private static final long serialVersionUID = 1L;
9. int id;
10. String name;
11. // double salary;
12. transient double salary;
13. 
    
14. public Employee(int id, String name, double salary) {
15. this.id = id;
16. this.name = name;
17. this.salary = salary;
18. }
19. 
    
20. @Override
21. public String toString() {
22. return "[id: " + id + ", name: " + name + ", salary: " + salary + "]";
23. }
24. }
25. 
    
26. public class WriteByObjectOutputStreamExe {
27. 
    
28. public static void main(String[] args) throws Exception {
29. File file = new File("D:\\data1.txt");
30. FileOutputStream fileStream = new FileOutputStream(file);
31. ObjectOutputStream objStream = new ObjectOutputStream(fileStream);
32. 
    
33. Employee e1 = new Employee(101, "suresh", 2000);
34. 
    
35. objStream.writeObject(e1);
36. objStream.flush();
37. objStream.close();
38. }
39. }

Output:
ͭ sr  com.ishaan.filehandling.Employee        I idL namet Ljava/lang/String;xp   et suresh

Read transient field data from a file using ObjectInputStream:

1. import java.io.File;
2. import java.io.FileInputStream;
3. import java.io.ObjectInputStream;
4. 
   
5. public class ReadFileByObjectInputStreamExe {
6. 
   
7. public static void main(String[] args) throws Exception {
8. File file = new File("D:\\data1.txt");
9. FileInputStream fileStream = new FileInputStream(file);
10. ObjectInputStream objStream = new ObjectInputStream(fileStream);
11. 
    
12. Employee emp = (Employee) objStream.readObject();
13. 
    
14. System.out.println(emp.toString());
15. objStream.close();
16. }
17. }

Output: 
[id: 101, name: suresh, salary: 0.0]

Write data from properties to xml file !!

Using Properties class:

1. import java.io.File;
2. import java.io.FileOutputStream;
3. import java.util.Properties;
4. 
   
5. public class WritePropertiesXmlFile {
6. public static void main(String[] args) throws Exception {
7. Properties properties = new Properties();
8. properties.setProperty("suresh", "2000");
9. properties.setProperty("mahesh", "1200");
10. properties.setProperty("ritesh", "2100");
11. 
    
12. File file = new File("D:\\test2.xml");
13. FileOutputStream fileOut = new FileOutputStream(file);
14. properties.storeToXML(fileOut, "balance-sheet");
15. fileOut.close();
16. }
17. }

Output:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
<properties>
<comment>balance-sheet</comment>
<entry key="ritesh">2100</entry>
<entry key="suresh">2000</entry>
<entry key="ishaan">0000</entry>
<entry key="mahesh">1200</entry>
</properties>

Write the data in properties file !!

Using Properties class:

1. import java.io.File;
2. import java.io.FileOutputStream;
3. import java.io.IOException;
4. import java.util.Properties;
5. 
   
6. public class WritePropertiesFiles {
7. 
   
8. public static void main(String[] args) throws IOException {
9. Properties prop = new Properties();
10. prop.setProperty("bangalore", "raju");
11. prop.setProperty("delhi", "ritesh");
12. prop.setProperty("chennai", "ishaan");
13. prop.setProperty("japan", "chet");
14. 
    
15. File file = new File("D:\\contacts.properties");
16. FileOutputStream fileStream = new FileOutputStream(file);
17. prop.store(fileStream, "store the contacts");
18. fileStream.close();
19. }
20. }

Output:
#store the contacts
#Sun Apr 29 20:22:15 IST 2018
delhi=ritesh
japan=chet
chennai=ishaan
bangalore=raju

Write the data using PrintWriter in java !!

Using PrintWriter:

1. import java.io.File;
2. import java.io.FileWriter;
3. import java.io.PrintWriter;
4. import java.io.IOException;
5. 
   
6. public class WriteByPrintWriterExe {
7. public static void main(String[] args) throws IOException {
8. File file = new File("D:\\data1.txt");
9. FileWriter fw = new FileWriter(file);
10. PrintWriter pw = new PrintWriter(fw);
11. 
    
12. for (int i = 0; i < 5; i++) {
13. pw.write("using PrintWriter !!");
14. pw.append("\n");
15. }
16. pw.close();
17. }
18. }

Output:
using PrintWriter !!
using PrintWriter !!
using PrintWriter !!
using PrintWriter !!
using PrintWriter !!

Write data in a file using ObjectOutputStream !!

Using ObjectOutputStream:

1. import java.io.File;
2. import java.io.FileOutputStream;
3. import java.io.ObjectOutputStream;
4. import java.io.Serializable;
5. 
   
6. class Employee implements Serializable {
7. 
   
8. private static final long serialVersionUID = 1L;
9. int id;
10. String name;
11. double salary;
12. // transient double salary;
13. 
    
14. public Employee(int id, String name, double salary) {
15. this.id = id;
16. this.name = name;
17. this.salary = salary;
18. }
19. 
    
20. @Override
21. public String toString() {
22. return "[id: " + id + ", name: " + name + ", salary: " + salary + "]";
23. }
24. }
25. 
    
26. public class WriteByObjectOutputStreamExe {
27. 
    
28. public static void main(String[] args) throws Exception {
29. File file = new File("D:\\data1.txt");
30. FileOutputStream fileStream = new FileOutputStream(file);
31. ObjectOutputStream objStream = new ObjectOutputStream(fileStream);
32. 
    
33. Employee e1 = new Employee(101, "suresh", 2000);
34. 
    
35. objStream.writeObject(e1);
36. objStream.flush();
37. objStream.close();
38. }
39. }

Output:

ͭ sr  com.ishaan.filehandling.Employee        I idD salaryL namet Ljava/lang/String;xp   e@ࠀ     t suresh

Write the data in a file using OutputStreamWriter !!

Using OutputStreamWriter: 

1. import java.io.File;
2. import java.io.FileOutputStream;
3. import java.io.OutputStreamWriter;
4. 
   
5. public class WriteByOutputStreamWriterExe {
6. 
   
7. public static void main(String[] args) throws Exception {
8. 
   
9. File file = new File("D:\\data1.txt");
10. FileOutputStream fileStream = new FileOutputStream(file);
11. OutputStreamWriter outputStream = new OutputStreamWriter(fileStream);
12. 
    
13. for (int i = 0; i < 5; i++) {
14. outputStream.write("using OutputStreamWriter !!");
15. outputStream.append("\n");
16. }
17. outputStream.close();
18. }
19. }

Output: 

using OutputStreamWriter !!
using OutputStreamWriter !!
using OutputStreamWriter !!
using OutputStreamWriter !!
using OutputStreamWriter !!

Write the data in a file using OutputStreamWriter !!

Using OutputStreamWriter: 

1. import java.io.File;
2. import java.io.FileOutputStream;
3. import java.io.OutputStreamWriter;
4. import java.io.BufferedWriter;
5. 
   
6. public class WriteByOutputStreamWriterExe {
7. 
   
8. public static void main(String[] args) throws Exception {
9. 
   
10. File file = new File("D:\\data1.txt");
11. FileOutputStream fileStream = new FileOutputStream(file);
12. OutputStreamWriter outputStream = new OutputStreamWriter(fileStream);
13. BufferedWriter bw = new BufferedWriter(outputStream);
14. 
    
15. for (int i = 0; i < 5; i++) {
16. bw.write("Using FileOutputStream. Isn't is interesting !! :)");
17. bw.newLine();
18. }
19. bw.close();
20. }
21. }

Output: 
Using FileOutputStream. Isn't is interesting !! :)
Using FileOutputStream. Isn't is interesting !! :)
Using FileOutputStream. Isn't is interesting !! :)
Using FileOutputStream. Isn't is interesting !! :)
Using FileOutputStream. Isn't is interesting !! :)

Write the data in a file using BufferedWriter !!

Using BufferedWriter:

1. import java.io.File;
2. import java.io.FileWriter;
3. import java.io.BufferedWriter;
4. import java.io.IOException;
5. 
   
6. public class WriteByBufferedWriterExe {
7. 
   
8. public static void main(String[] args) throws IOException {
9. String contents = "writing data using BufferedWriter. Isn't it interesting !!)";
10. 
    
11. File file = new File("D:\\data1.txt");
12. FileWriter fw = new FileWriter(file);
13. BufferedWriter bw = new BufferedWriter(fw);
14. 
    
15. for (int i = 0; i < 5; i++) {
16. bw.write(contents);
17. bw.newLine(); // bw.append("\n");
18. }
19. bw.close();
20. }
21. }

Output:

writing data using BufferedWriter. Isn't it interesting !! :)
writing data using BufferedWriter. Isn't it interesting !! :)
writing data using BufferedWriter. Isn't it interesting !! :)
writing data using BufferedWriter. Isn't it interesting !! :)
writing data using BufferedWriter. Isn't it interesting !! :)

Write the data in a file using Files class !!

Using Files class:

1. import java.nio.file.Files;
2. import java.nio.file.Paths;
3. import java.nio.file.Path;
4. import java.io.IOException;
5. 
   
6. public class WriteByFiles {
7. public static void main(String[] args) throws IOException {
8. String content = "writing data to data1.txt file using Files class !!";
9. String uri = "D:\\data1.txt";
10. Path path = Paths.get(uri);
11. Files.write(path, content.getBytes());
12. }
13. }

Output:
writing data to data1.txt file using Files class !!

Write same data multiple times in a file using FileWriter class !!

Using FileWriter:

1. import java.io.File;
2. import java.io.FileWriter;
3. 
   
4. public class WriteByFileWriterExe {
5. 
   
6. public static void main(String[] args) throws Exception {
7. File file = new File("D:\\data1.txt");
8. FileWriter fw = new FileWriter(file);
9. 
   
10. for (int i = 0; i < 5; i++) {
11. fw.write("using FileWriter !!");
12. fw.append("\n");
13. }
14. fw.close();
15. }
16. }

Output:

using FileWriter !!

using FileWriter !!

using FileWriter !!

using FileWriter !!

using FileWriter !!

Write the data in a file using FileWriter class !!

Using FileWriter: 

1. import java.io.File;
2. import java.io.FileWriter;
3. import java.io.IOException;
4. 
   
5. public class WriteByFileWriter {
6. 
   
7. public static void main(String[] args) throws IOException {
8. File file = new File("D:\\data1.txt");
9. FileWriter contacts = new FileWriter(file);
10. contacts.write("suresh - 9999999999\n");
11. contacts.write("ritesh - 0000000000\n");
12. contacts.write("mahesh - 8888888888");
13. contacts.close();
14. }
15. }

Output:

suresh - 9999999999

ritesh - 0000000000

mahesh - 8888888888

Difference b/w FileOutputStream and FileWriter in java ?

• FileOutputStream class is meant for writing streams of raw bytes / java object such as image data.
• FileWriter class is meant for writing character data to a file. 

• Similarity b/w FileOutputStream & FileWriter: Both the classes belongs to java.io package