Java IO

File myFile1 = new File("/home/rakovets/file.adoc");
File myFile2 = new File("/home/rakovets", "file.adoc");
File myDir  = new File("/home/rakovets");
File myFile3 = new File(myDir, "file.adoc");
URI ftpFile = new URI("ftp://localhost:21/rakovets/file.adoc");
File myFile4 = new File(ftpFile);

File myFile1 = new File("d:\\home\\rakovets\\file.adoc");
File myFile2 = new File("d:\\home\\rakovets", "file.adoc");
File myDir  = new File("d:\\home\\rakovets");
URI ftpFile = new URI("ftp://localhost:21/rakovets/file.adoc");
File myFile4 = new File(ftpFile);

try {
    File file = new File("tmp-file.txt");
    if (file.exists()) {
        System.out.printf("File '%s' already exists.\n",
                file.getCanonicalPath());
    } else {
        if (file.createNewFile()) {
            System.out.printf("New file '%s' is created.\n",
                    file.getCanonicalPath());
        } else {
            System.out.printf("New file '%s' isn't created.\n",
            file.getCanonicalPath());
        }
    }
} catch (IOException e) {
    e.printStackTrace();
}

New file '/home/rakovets/dev/course-java-core/tmp-file.txt' is created.

File '/home/rakovets/dev/course-java-core/tmp-file.txt' already exists.

public abstract class ExampleFiles {
    public static File INPUT_FILE = new File("src" + File.separator
            + "main" + File.separator
            + "resources" + File.separator
            + "example" + File.separator
            + "io" + File.separator
            + ".." + File.separator
            + "io" + File.separator
            + "input.file" + File.separator);
    public static File OUTPUT_FILE = new File("src" + File.separator
            + "main" + File.separator
            + "resources" + File.separator
            + "example" + File.separator
            + "io" + File.separator
            + "output.file" + File.separator);
    public static File TRANSFER_FILE = new File("src" + File.separator
            + "main" + File.separator
            + "resources" + File.separator
            + "example" + File.separator
            + "io" + File.separator
            + "transfer.file" + File.separator);
}

File fp = ExampleFiles.INPUT_FILE;

if (fp.isFile()) {
    System.out.printf("Name: %s\n", fp.getName());
    System.out.printf("Parent: %s\n", fp.getParent());
    System.out.printf("Path: %s\n", fp.getPath());
    System.out.printf("Absolute path: %s\n", fp.getAbsolutePath());
    try {
        System.out.printf("Canonical path: %s\n", fp.getCanonicalPath());
    } catch (IOException e) {
        e.printStackTrace();
    }
    System.out.printf("File size: %s\n", fp.length());
    System.out.printf("Last Modified: %s\n",
            DateUtil.convertFromEpochMilli(fp.lastModified()));
    System.out.printf("Readable: %s\n", fp.canRead());
    System.out.printf("Writable: %s\n", fp.canWrite());
    System.out.printf("Executable: %s\n", fp.canExecute());
}

Name: input.txt
Parent: src/main/resources/example/io/../io
Path: src/main/resources/example/io/../io/input.txt
Absolute path: /home/rakovets/dev/course-java-core/src/main/resources/example/io/../io/input.txt
Canonical path: /home/rakovets/dev/course-java-core/src/main/resources/example/io/input.txt
File size: 0
Last Modified: 2021-05-09T07:51:16.945
Readable: true
Writable: true
Executable: false

File dir = new File("src" + File.separator + "main");
if (dir.exists() && dir.isDirectory()) {
    File[] files = dir.listFiles();
    if (files != null) {
        System.out.printf("%-20s%-10s%s\n", "Path", "Size", "Last modified");
        for (File file : files) {
            System.out.printf("%-20s%-10d%s\n", file.getPath(), file.length(),
                    DateUtil.convertFromEpochMilli(file.lastModified()));
        }
    }
}

File root = File.listRoots()[0];
System.out.printf("\nDirectory: %s\n", root.getPath());
System.out.printf("Total space:\t%,d\n", root.getTotalSpace());
System.out.printf("Usable space:\t%,d\n", root.getUsableSpace());

Path                Size      Last modified
src/main/java       6         2021-04-20T18:25:14.146
src/main/resources  30        2021-05-06T19:13:58.817

Directory:		/
Total space:	160,000,114,688 byte
Usable space:	132,915,920,896 byte

public interface Closeable extends AutoCloseable {
    public void close() throws IOException;
}

InputStream fin = null;
try {
    fin = new FileInputStream(ExampleFiles.INPUT_FILE);
    int i = -1;
    while ((i = fin.read()) != -1) {
        System.out.print((char) i);
    }
} catch (IOException e) {
    System.out.println(e.getMessage());
} finally {
    try {
        if (fin != null) {
            fin.close();
        }
    } catch (IOException e) {
        System.out.println(e.getMessage());
    }
}

What is Lorem Ipsum?

Lorem Ipsum is simply dummy text of the printing and typesetting industry.

try (InputStream fin = new FileInputStream(ExampleFiles.INPUT_FILE)) {
    int i = -1;
    while ((i = fin.read()) != -1) {
        System.out.print((char) i);
    }
} catch (IOException e) {
    System.out.println(e.getMessage());
}

What is Lorem Ipsum?

Lorem Ipsum is simply dummy text of the printing and typesetting industry.

byte[] bytes = {-128, -127, -1, 0, 1, 127};
InputStream bais = new ByteArrayInputStream(bytes);

int readByte;
for (byte b : bytes) {
    readByte = bais.read();
    System.out.printf("Element: '%d' - Read byte: `%d`\n", b, readByte);
}

try (OutputStream fos = new FileOutputStream(ExampleFiles.OUTPUT_FILE);
     OutputStream fos2 = new FileOutputStream(ExampleFiles.OUTPUT_FILE_2);
     ByteArrayOutputStream bout = new ByteArrayOutputStream()) {

    bout.write("Hell to world!".getBytes());
    bout.writeTo(fos);
    bout.writeTo(fos2);

    bout.flush();
} catch (IOException e) {
    e.printStackTrace();
}

Hell to world!

try (InputStream fin = new FileInputStream(ExampleFiles.INPUT_FILE);
     InputStream bin = new BufferedInputStream(fin)) {
    int i;
    while ((i = bin.read()) != -1) {
        System.out.print((char) i);
    }
} catch (IOException e) {
    e.printStackTrace();
}

What is Lorem Ipsum?

Lorem Ipsum is simply dummy text of the printing and typesetting industry.

try (OutputStream fout = new FileOutputStream(ExampleFiles.OUTPUT_FILE);
     OutputStream bout = new BufferedOutputStream(fout)) {
    String s = "Hell to world by BufferedOutputStream!";
    byte[] stringAsBytes = s.getBytes();
    bout.write(stringAsBytes);
    bout.flush();
} catch (IOException e) {
    e.printStackTrace();
}

Hell to world by BufferedOutputStream!

try (OutputStream file = new FileOutputStream(ExampleFiles.OUTPUT_FILE);
     DataOutputStream data = new DataOutputStream(file)) {
    data.writeInt(12);
    data.writeDouble(12.34);
    data.flush();
} catch (IOException e) {
    e.printStackTrace();
}

   @(�z�G�

try (InputStream fis = new FileInputStream(ExampleFiles.TRANSFER_FILE);
     DataInputStream dis = new DataInputStream(fis)) {
    int readInt = dis.readInt();
    double readDouble = dis.readDouble();
    System.out.println(readInt);
    System.out.println(readDouble);
} catch (IOException e) {
    e.printStackTrace();
}

12
12.34

try (Writer fw = new FileWriter(ExampleFiles.OUTPUT_FILE)) {
    fw.write("Hell to world by FileWriter!");
} catch (IOException e) {
    e.printStackTrace();
}

Hell to world by FileWriter!

try (Reader fr = new FileReader(ExampleFiles.INPUT_FILE)) {
    int i;
    while ((i = fr.read()) != -1) {
        System.out.print((char) i);
    }
} catch (IOException e) {
    e.printStackTrace();
}

What is Lorem Ipsum?

Lorem Ipsum is simply dummy text of the printing and typesetting industry.

try (Writer fw = new FileWriter(ExampleFiles.OUTPUT_FILE);
     Writer bw = new BufferedWriter(fw)) {
    bw.write("Hell to world by BufferedWriter!");
} catch (IOException e) {
    e.printStackTrace();
}

Hell to world by BufferedWriter!

try (Reader fr = new FileReader(ExampleFiles.INPUT_FILE);
     BufferedReader br = new BufferedReader(fr)) {
    String line;
    while ((line = br.readLine()) != null) {
        System.out.println(line);
    }
} catch (IOException e) {
    e.printStackTrace();
}

public interface Serializable {
}

import java.io.Serializable;

public class Person implements Serializable {
    private final String name;
    private final transient double height;

    public Person(String name, double height) {
        this.name = name;
        this.height = height;
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", height=" + height +
                '}';
    }
}

Person tom = new Person("Tom", 180);
try (OutputStream fos = new FileOutputStream(ExampleFiles.TRANSFER_FILE);
     ObjectOutputStream oos = new ObjectOutputStream(fos)) {
    oos.writeObject(tom);
    oos.flush();
} catch (IOException e) {
    e.printStackTrace();
}

�� sr 5com.rakovets.course.java.core.example.io.model.Person�4���M; 
L namet Ljava/lang/String;xpt Tom

try (InputStream fis = new FileInputStream(ExampleFiles.TRANSFER_FILE);
     ObjectInputStream ois = new ObjectInputStream(fis)) {
    Object readObject = ois.readObject();
    System.out.println(readObject);
} catch (IOException | ClassNotFoundException e) {
    e.printStackTrace();
}

Person{name='Tom', height=0.0}

java.io.InvalidClassException:
    com.rakovets.course.java.core.example.io.model.Person;
    local class incompatible:
        stream classdesc serialVersionUID = 5181901209139047180,
        local class serialVersionUID = -8989654875390893074

import java.io.Serializable;

public class Person implements Serializable {
    private static final long serialVersionUID = -1909254337192130771L;

    private final String name;
    private final transient double height;

    public Person(String name, double height) {
        this.name = name;
        this.height = height;
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", height=" + height +
                '}';
    }
}

Formatter fmt = new Formatter();
Formatter simpleFormatter = fmt.format(
        "Formatting %s is easy %d %f.",
        "with Java", 42, 33.3);
System.out.println(simpleFormatter);

Formatting with Java is easy 42 33.300000.

Formatter decimalFormatter = new Formatter();
for (double i = 1000.0; i < 1.0e+10; i *= 100) {
    decimalFormatter.format("%g ", i);
    System.out.println(decimalFormatter);
}

1000.00
1000.00 100000
1000.00 100000 1.00000e+07
1000.00 100000 1.00000e+07 1.00000e+09

Formatter anotherSystemFormatter = new Formatter();
anotherSystemFormatter.format("Hex: %x. Octal:  %o",  42, 42);
System.out.println(anotherSystemFormatter);

Hex: 2a. Octal:  52

Formatter alignmentFormatter = new Formatter();
alignmentFormatter.format("|%8.2f|", 123.456);
System.out.println(alignmentFormatter);

alignmentFormatter = new Formatter();
alignmentFormatter.format("|%-8.2f|", 123.456);
System.out.println(alignmentFormatter);

|  123.46|
|123.46  |

Formatter orderFormatter = new Formatter();
orderFormatter.format("%3$d  %1$d %2$d", 1, 22, 333);
System.out.println(orderFormatter);

333  1 22

System.out.printf("%3$d  %1$d %2$d", 1, 22, 333);

333  1 22

Scanner inScanner = new Scanner(System.in);
int i;
while (inScanner.hasNextInt()) {
    i = inScanner.nextInt();
    System.out.println(i);
}

try (OutputStream fout = new FileOutputStream(ExampleFiles.OUTPUT_FILE);
     PrintStream pout = new PrintStream(fout)) {
    pout.println(2021);
    pout.println("Hell to world!");
} catch (IOException e) {
    e.printStackTrace();
}

2021
Hell to world!

double[] javaVersions = {1.1, 1.22, 1.333, 1.4444, 5.0};
try (FileWriter fw = new FileWriter(ExampleFiles.OUTPUT_FILE, false);
     BufferedWriter bw = new BufferedWriter(fw);
     PrintWriter pw = new PrintWriter(bw)) {
    for (double version : javaVersions) {
        pw.printf("Java %.2g\n", version);
    }
} catch (IOException e) {
    System.err.println("ошибка открытия потока " + e);
    System.exit(1);
}

Console console = System.console();
System.out.println("Enter your name: ");
try {
    String name = console.readLine();
    System.out.printf("Welcome %s!\n", name);
} catch (NullPointerException e) {
    System.out.println("\nThrew: NullPointerException\n" +
            "No console associated to the JVM.\n" +
            "Please read JavaDoc for method 'System.console()`");
}

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class Program {
    public static void main(String[] args) {
        String filename = "C:\\SomeDir\\notes.txt";
        try (ZipOutputStream zout = new ZipOutputStream(new FileOutputStream("C:\\SomeDir\\output.zip"));
             FileInputStream fis = new FileInputStream(filename);) {
            ZipEntry entry1 = new ZipEntry("notes.txt");
            zout.putNextEntry(entry1);
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            zout.write(buffer);
            zout.closeEntry();
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
}

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class Program {
    public static void main(String[] args) {
        try (ZipInputStream zin = new ZipInputStream(new FileInputStream("C:\\SomeDir\\output.zip"))) {
            ZipEntry entry;
            String name;
            long size;
            while ((entry = zin.getNextEntry()) != null) {
                name = entry.getName();
                size = entry.getSize();
                System.out.printf("File name: %s \t File size: %d \n", name, size);
                FileOutputStream fout = new FileOutputStream("C:\\somedir\\new" + name);
                for (int c = zin.read(); c != -1; c = zin.read()) {
                    fout.write(c);
                }
                fout.flush();
                zin.closeEntry();
                fout.close();
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
}