Example usage for java.io RandomAccessFile length

Introduction

In this page you can find the example usage for java.io RandomAccessFile length.

Prototype

public native long length() throws IOException;

Source Link

Document

Returns the length of this file.

Usage

From source file:RandomFileTest.java

public static void main(String[] args) {
    Employee[] staff = new Employee[3];

    staff[0] = new Employee("Harry Hacker", 35000);
    staff[1] = new Employee("Carl Cracker", 75000);
    staff[2] = new Employee("Tony Tester", 38000);
    try {/*ww w .  ja  va2s . c o m*/
        DataOutputStream out = new DataOutputStream(new FileOutputStream("employee.dat"));
        for (int i = 0; i < staff.length; i++)
            staff[i].writeData(out);
        out.close();
    } catch (IOException e) {
        System.out.print("Error: " + e);
        System.exit(1);
    }

    try {
        RandomAccessFile in = new RandomAccessFile("employee.dat", "r");
        int count = (int) (in.length() / Employee.RECORD_SIZE);
        Employee[] newStaff = new Employee[count];

        for (int i = count - 1; i >= 0; i--) {
            newStaff[i] = new Employee();
            in.seek(i * Employee.RECORD_SIZE);
            newStaff[i].readData(in);
        }
        for (int i = 0; i < newStaff.length; i++)
            newStaff[i].print();
    } catch (IOException e) {
        System.out.print("Error: " + e);
        System.exit(1);
    }
}

---

From source file:SenBench.java

public static void main(String[] args) {
    try {// ww w . j  av  a  2 s.  c  o m
        if (args.length == 0) {
            System.out.println("usage: java SenBench file [file ..]");
            System.exit(2);
        }

        StringTagger tagger = StringTagger.getInstance(Locale.JAPANESE);

        long processed = 0;
        long nbytes = 0;
        long nchars = 0;

        long start = System.currentTimeMillis();
        for (int a = 0; a < args.length; a++) {
            String text = "";
            try {
                RandomAccessFile raf = new RandomAccessFile(args[a], "r");
                byte[] buf = new byte[(int) raf.length()];
                raf.readFully(buf);
                raf.close();
                text = new String(buf, encoding);
                nbytes += buf.length;
                nchars += text.length();
            } catch (IOException ioe) {
                log.error(ioe);
                continue;
            }

            long s_start = System.currentTimeMillis();
            for (int c = 0; c < repeat; c++)
                doWork(tagger, text);
            long s_end = System.currentTimeMillis();
            processed += (s_end - s_start);
        }
        long end = System.currentTimeMillis();
        System.out.println("number of files: " + args.length);
        System.out.println("number of repeat: " + repeat);
        System.out.println("number of bytes: " + nbytes);
        System.out.println("number of chars: " + nchars);
        System.out.println("total time elapsed: " + (end - start) + " msec.");
        System.out.println("analysis time: " + (processed) + " msec.");
    } catch (Exception e) {
        e.printStackTrace(System.err);
        System.exit(1);
    }
}

---

From source file:MeCabBench.java

public static void main(String[] args) {
    try {//from  w  w  w  .  ja  va  2  s .co  m
        if (args.length == 0) {
            System.out.println("usage: java MeCabBench file [file ..]");
            System.exit(2);
        }

        Tagger tagger = new Tagger(new String[] { "java", "-d", dicPath });

        long processed = 0;
        long nbytes = 0;
        long nchars = 0;

        long start = System.currentTimeMillis();
        for (int a = 0; a < args.length; a++) {
            String text = "";
            try {
                RandomAccessFile raf = new RandomAccessFile(args[a], "r");
                byte[] buf = new byte[(int) raf.length()];
                raf.readFully(buf);
                raf.close();
                text = new String(buf, encoding);
                nbytes += buf.length;
                nchars += text.length();
            } catch (IOException ioe) {
                log.error(ioe);
                continue;
            }

            long s_start = System.currentTimeMillis();
            for (int c = 0; c < repeat; c++)
                doWork(tagger, text);
            long s_end = System.currentTimeMillis();
            processed += (s_end - s_start);
        }
        long end = System.currentTimeMillis();
        System.out.println("number of files: " + args.length);
        System.out.println("number of repeat: " + repeat);
        System.out.println("number of bytes: " + nbytes);
        System.out.println("number of chars: " + nchars);
        System.out.println("total time elapsed: " + (end - start) + " msec.");
        System.out.println("analysis time: " + (processed) + " msec.");
    } catch (Exception e) {
        e.printStackTrace(System.err);
        System.exit(1);
    }
}

---

From source file:RandomFileTest.java

public static void main(String[] args) {
    Employee[] staff = new Employee[3];

    staff[0] = new Employee("Carl Cracker", 75000, 1987, 12, 15);
    staff[1] = new Employee("Harry Hacker", 50000, 1989, 10, 1);
    staff[2] = new Employee("Tony Tester", 40000, 1990, 3, 15);

    try {//from  w w  w  .j  av  a2s.  c o  m
        // save all employee records to the file employee.dat
        DataOutputStream out = new DataOutputStream(new FileOutputStream("employee.dat"));
        for (Employee e : staff)
            e.writeData(out);
        out.close();

        // retrieve all records into a new array
        RandomAccessFile in = new RandomAccessFile("employee.dat", "r");
        // compute the array size
        int n = (int) (in.length() / Employee.RECORD_SIZE);
        Employee[] newStaff = new Employee[n];

        // read employees in reverse order
        for (int i = n - 1; i >= 0; i--) {
            newStaff[i] = new Employee();
            in.seek(i * Employee.RECORD_SIZE);
            newStaff[i].readData(in);
        }
        in.close();

        // print the newly read employee records
        for (Employee e : newStaff)
            System.out.println(e);
    } catch (IOException e) {
        e.printStackTrace();
    }
}

---

From source file:Main.java

public static void main(String[] args) {
    try {//from www . j av  a  2 s  .c  om
        String s = "Hello world from java2s.com";

        RandomAccessFile raf = new RandomAccessFile("c:/test.txt", "rw");

        // write something in the file
        raf.writeUTF(s);

        // set the file pointer at 0 position
        raf.seek(0);

        // create an array equal to the length of raf
        byte[] arr = new byte[(int) raf.length()];

        // read the file
        raf.readFully(arr);

        // create a new string based on arr
        String s2 = new String(arr);

        System.out.println(s2);
        raf.close();
    } catch (IOException ex) {
        ex.printStackTrace();
    }

}

---

From source file:Main.java

public static void main(String[] args) throws Exception {
    RandomAccessFile raf = new RandomAccessFile("books.dat", "rw");

    String books[] = new String[5];
    books[0] = "A";
    books[1] = "B";
    books[2] = "C";
    books[3] = "D";
    books[4] = "E";

    for (int i = 0; i < books.length; i++) {
        raf.writeUTF(books[i]);//from   www .j a v  a 2 s .  c o m
    }
    raf.seek(raf.length());
    raf.writeUTF("Servlet & JSP Programming");

    raf.seek(0);

    while (raf.getFilePointer() < raf.length()) {
        System.out.println(raf.readUTF());
    }
}

---

From source file:Main.java

public static void main(String[] args) {
    try {//from   ww  w .  java2  s.c  o  m
        RandomAccessFile raf = new RandomAccessFile("c:/test.txt", "rw");

        raf.writeUTF("Hello World from java2s.com");

        // set the file pointer at 0 position
        raf.seek(0);

        // print the string
        System.out.println(raf.readUTF());

        // print current length
        System.out.println(raf.length());

        // set the file length to 30
        raf.setLength(30);

        System.out.println(raf.length());
        raf.close();
    } catch (IOException ex) {
        ex.printStackTrace();
    }

}

---

From source file:Main.java

public static void main(String[] args) {
    try {//from  w w  w  . j ava  2 s .com

        RandomAccessFile raf = new RandomAccessFile("c:/test.txt", "rw");

        // write something in the file
        raf.writeUTF("java2s.com Hello World");

        // set the file pointer at 0 position
        raf.seek(0);

        // read and print the contents of the file
        System.out.println(raf.readUTF());

        // print the length of the file
        System.out.println(raf.length());

        // write something more in the file
        raf.writeUTF("This is an example");

        // print the length of the file
        System.out.println(raf.length());
        raf.close();
    } catch (IOException ex) {
        ex.printStackTrace();
    }

}

---

From source file:Diff.java

public static void main(String args[]) {
    RandomAccessFile fh1 = null;
    RandomAccessFile fh2 = null;/*from   w  w  w  . j av  a 2 s  .c om*/
    int bufsize; // size of smallest file
    long filesize1 = -1;
    long filesize2 = -1;
    byte buffer1[]; // the two file caches
    byte buffer2[];
    // check what you get as command-line arguments
    if (args.length == 0 || args[0].equals("?")) {
        System.err.println("USAGE: java Diff <file1> <file2> | ?");
        System.exit(0);
    }
    // open file ONE for reading
    try {
        fh1 = new RandomAccessFile(args[0], "r");
        filesize1 = fh1.length();
    } catch (IOException ioErr) {
        System.err.println("Could not find " + args[0]);
        System.err.println(ioErr);
        System.exit(100);
    }
    // open file TWO for reading
    try {
        fh2 = new RandomAccessFile(args[1], "r");
        filesize2 = fh2.length();
    } catch (IOException ioErr) {
        System.err.println("Could not find " + args[1]);
        System.err.println(ioErr);
        System.exit(100);
    }
    if (filesize1 != filesize2) {
        System.out.println("Files differ in size !");
        System.out.println("'" + args[0] + "' is " + filesize1 + " bytes");
        System.out.println("'" + args[1] + "' is " + filesize2 + " bytes");
    }
    // allocate two buffers large enough to hold entire files
    bufsize = (int) Math.min(filesize1, filesize2);
    buffer1 = new byte[bufsize];
    buffer2 = new byte[bufsize];
    try {
        fh1.readFully(buffer1, 0, bufsize);
        fh2.readFully(buffer2, 0, bufsize);

        for (int i = 0; i < bufsize; i++) {
            if (buffer1[i] != buffer2[i]) {
                System.out.println("Files differ at offset " + i);
                break;
            }
        }
    } catch (IOException ioErr) {
        System.err.println("ERROR: An exception occurred while processing the files");
        System.err.println(ioErr);
    } finally {
        try {
            fh1.close();
            fh2.close();
        } catch (IOException ignored) {
        }
    }
}

---

From source file:CreateEmployeeFile.java

public static void main(String[] args) throws Exception {
    String[] fnames = { "A", "B", "C" };

    String[] lnames = { "a", "b", "c" };

    String[] addresses = { "Box 100", "55 Street", "6 Lane" };

    byte[] ages = { 46, 59, 32 };

    double[] salaries = { 5.0, 6.0, 3.0 };

    RandomAccessFile raf = new RandomAccessFile("employee.dat", "rw");

    EmployeeRecord er = new EmployeeRecord();

    for (int i = 0; i < fnames.length; i++) {
        er.setFirstName(fnames[i]);/*w w w .  j ava2s  .  c  o  m*/
        er.setLastName(lnames[i]);
        er.setAddress(addresses[i]);
        er.setAge(ages[i]);
        er.setSalary(salaries[i]);
        er.write(raf);
    }
    raf = new RandomAccessFile("employee.dat", "rw");

    er = new EmployeeRecord();

    int numRecords = (int) raf.length() / er.size();

    for (int i = 0; i < numRecords; i++) {
        er.read(raf);

        System.out.print(er.getFirstName() + " ");
        System.out.print(er.getLastName() + " ");
        System.out.print(er.getAddress() + " ");
        System.out.print(er.getAge() + " ");
        System.out.println(er.getSalary());
    }
    raf.seek(0);
    for (int i = 0; i < numRecords; i++) {
        er.read(raf);
        if (er.getAge() >= 55) {
            er.setSalary(0.0);
            raf.seek(raf.getFilePointer() - er.size());
            er.write(raf);
            raf.seek(raf.getFilePointer() - er.size());
            er.read(raf);
        }
        System.out.print(er.getFirstName() + " ");
        System.out.print(er.getLastName() + " ");
        System.out.print(er.getAddress() + " ");
        System.out.print(er.getAge() + " ");
        System.out.println(er.getSalary());
    }

}

---

• «
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21
• 22
• 23
• »