Java IO.pdf - Nguyen Dang Binh

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Java I/O java.awt.image.renderable ParameterBlock java.beans PropertyChangeSupport, VetoableChangeSupport java.beans.beancontext BeanContextChildSupport, BeanContextSupport java.io Externalizable, File, FilePermission, FilePermissionCollection, ObjectStreamClass java.net InetAddress, SocketPermissionCollection, URL SocketPermission, java.rmi MarshalledObject java.rmi.activation ActivationDesc, ActivationGroupDesc, ActivationGroupID, ActivationID java.rmi.dgc Lease, VMID java.rmi.server ObjID, RemoteObject, UID AllPermissionCollection, BasicPermission, BasicPermissionCollection, CodeSource, GuardedObject, Identity, Key, KeyPair, Permission, java.security PermissionCollection, Permissions, PermissionsHash, SecureRandomSpi, SignedObject, UnresolvedPermission, UnresolvedPermissionCollection BreakIterator, Collator, DateFormatSymbols, java.text DecimalFormatSymbols, TextBoundaryData, WordBreakTable Format, SpecialMapping, UnicodeClassMapping, ArrayList, BitSet, Calendar, Date, EventObject, java.util HashMap, HashSet, Hashtable, LinkedList, Locale, PropertyPermissionCollection, Random, TimeZone, TreeMap, TreeSet, Vector javax.swing.table AbstractTableModel, DefaultTableCellRenderer, DefaultTableColumnModel, DefaultTableModel, TableColumn javax.swing.text AbstractDocument, SimpleAttributeSet, TabSet, TabStop EditorKit, StringContent, GapContent, StyleContext, javax.swing.tree DefaultMutableTreeNode, DefaultTreeModel, DefaultTreeSelectionModel, TreePath You can glean some general principles about what classes are and are not likely to be serializable. Exceptions, errors, and other throwable objects are always serializable. Streams, readers and writers, and most other I/O classes are not serializable. Beyond these general rules, you can look at specific packages. AWT components, containers, and events are serializable, but event adapters, image filters, and AWT classes that abstract OS-dependent features are not. java.beans classes are not serializable. Type wrapper classes are serializable except for Void ; most other java.lang classes are not. Reflection classes are not serializable. java.math classes are serializable. URLs are serializable. Socket, URLConnection, and most other java.net classes are not. Container classes are serializable (though see the next section). Compression classes are not serializable. Overall, there are five reasons why a class may not be serializable: 1. It is too closely tied to native code (java.util.zip.Deflater). 2. The object's state depends on the internals of the virtual machine or the runtime environment and thus may change from run to run. (java.lang.Thread , java.io.InputStream , java.io.FileDescriptor, java.awt.PrintJob). 243
Java I/O 3. Serializing it is a potential security risk (java.lang.SecurityManager, java.security.MessageDigest). 4. The class is mostly a holder for static methods without any real internal state (java.beans.Beans, java.lang.Math). 5. The person who wrote the class simply didn't think about serialization. 11.5.1 Classes That Implement Serializable but Aren't Just because a class may be serialized does not mean that it can be serialized. Several problems can prevent a class that implements Serializable from actually being serialized. Attempting to serialize such a class throws a NotSerializableException, a kind of IOException: public class NotSerializableException extends ObjectStreamException 11.5.1.1 Problem 1: References to nonserializable objects The first common problem that prevents a serializable class from being serialized is that its graph contains objects that do not implement Serializable. The graph of an object is the collection of all objects that the object holds references to, and all the objects those objects hold references to, and all the objects those objects hold references to, and so on, until there are no more connected objects that haven't appeared in the collection. For an object to be serialized, all the objects it holds references to must also be serializable, and all the objects they hold references to must be serializable, and so on. For instance, consider this skeleton of a class: import java.applet.*; import java.net.*; public class MyNetworkingApplet extends Applet { } Socket theConnection; //... MyNetworkingApplet extends Applet, which extends Panel, which extends Container, which extends Component, which implements Serializable. Thus, MyNetworkingApplet should be serializable. However, MyNetworkingApplet contains a reference to a java.net.Socket object. Socket is not a serializable class. Therefore, if you try to pass a MyNetworkingApplet instance to writeObject(), a NotSerializableException will be thrown. The situation is even worse for container classes like Hashtable and Vector. Since serialization performs a deep copy to the output stream, storing even a single nonserializable class inside a vector or hash table prevents it from being serialized. Since the objects stored in a container can vary from program to program or run to run, there's no sure-fire way to know whether or not a particular instance of a container class can be serialized, short of trying it. The same problem commonly occurs in applets and other GUI programs that use a Container to hold many different components connected by events. If any of the objects in the container 244
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Java I/O Elliotte Rusty Harold Publ
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III: Filter Streams ...............
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V: Appendixes .....................
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Preface Java I/O In many ways this
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Java I/O operations from moving byt
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Chapter 9 Chapter 10 Java I/O Chapt
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Chapter 17 Java I/O lining up the d
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Security Issues Java I/O I don't kn
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Java I/O Finally, although many of
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Part I: Basic I/O Java I/O 13
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Java I/O The word stream is derived
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Java I/O The java.util.jar package
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Java I/O For instance, according to
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Java I/O Java understands several d
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Java I/O commonly use an eight-bit
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Java I/O For the most part, these c
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Figure 1.1. An xterm console on Uni
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Java I/O If you absolutely must use
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Java I/O in Apple's Macintosh Runti
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Java I/O to work inside a web brows
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Java I/O bit pattern to a particula
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Java I/O The output is the same as
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OutputStream out = new NullOutputSt
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Figure 2.1. The StreamedTextArea co
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Java I/O When you call read(), you
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Java I/O try { byte[] b = new byte[
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Java I/O Once you have closed an in
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public class StreamCopier { } publi
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Chapter 4. File Streams Java I/O Un
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} } for (int i = 0; i < args.length
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Java I/O The FileOutputStream class
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Java I/O ASCII format is the defaul
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} } } Java I/O if (hex >= 16) Syste
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Java I/O Finally, many HTML files c
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Java I/O In particular, URL connect
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Java I/O Example 5.3 uses these ste
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Java I/O many available ports but o
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Java I/O inspecting the port. It kn
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} } } String response = "Hello " +
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} public void actionPerformed(Actio
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Chapter 6. Filter Streams Java I/O
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Java I/O output stream, out. Among
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Java I/O SourceFile???StringExtract
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6.3 Buffered Streams Java I/O Buffe
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public boolean markSupported() Java
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The compiler rewrites this complica
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public class TeeCopier { } public s
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} } try { FileInputStream fin = new
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} public int available() throws IOE
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public class HexFilter extends Dump
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} } StreamCopier.copy(in, out); in.
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Java I/O the java.io.DataOutput int
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Java I/O Although other schemes are
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} public static void main(String ar
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Java I/O Since Java has no unsigned
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dout.close(); } catch (IOException
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Java I/O The DataInputStream class
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Java I/O The readLine() method read
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7.7 Miscellaneous Methods Java I/O
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public synchronized void write(int
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** * Writes a 4 byte Java float to
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} * possible that this number is te
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*/ public byte readByte(int b) thro
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} Java I/O long byte4 = in.read();
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7.9 Thread Safety Java I/O The Litt
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public static void main(String[] ar
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Table 7.2. Command-Line Switches fo
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} protected void fill() throws IOEx
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Chapter 8. Streams in Memory Java I
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UDP Byte array input and output str
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} } try { // So that the buffer doe
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Java I/O Otherwise, these classes j
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} } catch (IOException e) { // prob
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Java I/O legally unencumbered—tha
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Java I/O if it doesn't, it will com
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Java I/O The first method fills the
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public class DirectDeflater { } pub
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9.1.2.1 Constructing inflaters Ther
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9.1.2.7 An example Java I/O Example
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Java I/O stream itself, without hav
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Java I/O Each inflater input stream
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Java I/O This writes all remaining
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} } } FileOutputStream fout = new F
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} } } catch (IOException e) {System
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Java I/O Normally, the name argumen
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% java FancyZipLister temp.zip test
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Java I/O All high-order Unicode byt
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Java I/O the files to be stored in
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9.3.3.2 Open the next zip entry Jav
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Java I/O Better checksum schemes us
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} } int b; while ((b = in.read()) !
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Java I/O example, under Unix, to ma
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Java I/O archive. If the signatures
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Java I/O public JarFile(String file
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Java I/O The java.util.jar.Attribut
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9.5.7 Manifest Java I/O What the ja
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public ZipEntry getNextEntry() thro
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Java I/O so throw a java.lang.Unsup
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within the space of the next few li
Page 200 and 201: Chapter 10. Cryptographic Streams J
Page 202 and 203: Java I/O • It should be difficult
Page 204 and 205: Figure 10.1. The four steps to calc
Page 206 and 207: Java I/O you only want to detect si
Page 208 and 209: public void reset() Java I/O In pra
Page 210 and 211: Java I/O After each successful call
Page 212 and 213: } byte[] result = md.digest(); for
Page 214 and 215: } } catch (Exception e) {System.err
Page 216 and 217: public class EasyFileDigest { publi
Page 218 and 219: Java I/O them your encryption (publ
Page 220 and 221: Java I/O DES, triple DES (DESede),
Page 222 and 223: IDEA RC2 RC4 Blowfish Java I/O The
Page 224 and 225: Figure 10.2. Encrypting data Java I
Page 226 and 227: } } catch (NoSuchAlgorithmException
Page 228 and 229: } } Java I/O } catch (InvalidKeySpe
Page 230 and 231: SecretKey blowfishKey = blowfishKey
Page 232 and 233: Java I/O public final byte[] doFina
Page 234 and 235: Java I/O A CipherInputStream object
Page 236 and 237: 10.6.2 CipherOutputStream CipherOut
Page 238 and 239: } } byte[] newDigest = sha.digest()
Page 240 and 241: } } else if (args[firstFile].equals
Page 242 and 243: Java I/O Note how little we had to
Page 244 and 245: Chapter 11. Object Serialization Ja
Page 246 and 247: Java I/O To write an object onto a
Page 248 and 249: Java I/O Needless to say, this is a
Page 252 and 253: Java I/O are not serializable, then
Page 254 and 255: 11.5.1.5 Making nonserializable fie
Page 256 and 257: Java I/O output streams, but DataIn
Page 258 and 259: Figure 11.2. The serialver GUI Java
Page 260 and 261: public SerializableZipFile(File fil
Page 262 and 263: public class NetworkWindow extends
Page 264 and 265: private void writeObject(ObjectOutp
Page 266 and 267: } } Vector v = (Vector) oin.readObj
Page 268 and 269: Java I/O the resolveClass() method
Page 270 and 271: Example 11.6. Person import java.ut
Page 272 and 273: public class SealedPoint { } public
Page 274 and 275: Chapter 12. Working with Files Java
Page 276 and 277: Java I/O not begin with an @. Under
Page 278 and 279: Java I/O placing a minus sign befor
Page 280 and 281: Java I/O rush to snap up all the go
Page 282 and 283: System Properties System properties
Page 284 and 285: Java I/O complete list of the ASCII
Page 286 and 287: Win32 index.html MacOS index.html N
Page 288 and 289: Java I/O The path argument should b
Page 290 and 291: Java I/O assume the array returned
Page 292 and 293: Example 12.2. Paths import java.io.
Page 294 and 295: String canonicalPath = f.getCanonic
Page 296 and 297: Java I/O The isHidden() method, onl
Page 298 and 299: 12.3.4 Manipulating Files Java I/O
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fin.close(); src.delete(); Java I/O
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public int hashCode() public boolea
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public class DirList { } File direc
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12.4 Filename Filters Java I/O You
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} } for (int i = 0; i < htmlFiles.l
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public RandomAccessFile(File file,
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Java I/O • Do not parse pathnames
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Figure 13.2. Motif standard Open di
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Java I/O Example 13.1 is a program
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} } // Work around annoying AWT non
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} // Clean up our windows, they won
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13.2.2 Displaying File Choosers Jav
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13.2.5 Custom Dialogs Java I/O File
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Figure 13.4. The choosable file fil
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Example 13.7. JavaChooser import ja
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13.2.7 Selecting Directories Java I
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public void setFileView(fileView) p
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13.2.12.1 Action events Java I/O Wh
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public TextFilePreview(JFileChooser
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13.3 File Viewer, Part 6 Java I/O W
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} } } theView.setText(""); OutputSt
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} } return deflated.isSelected(); p
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Java I/O Chapter 14. Multilingual C
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Java I/O the upper 128 characters o
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makeBlock("Telugu", 0x0C00, 0x0C7F)
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} } for (int i = 0; i < names.lengt
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14.3 Unicode Escapes Java I/O Curre
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0 0 0 0 0 x10 x9 x8 x7 x6 x5 x4 x3
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Character g = new Character('g'); C
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Java I/O two Latin letters. In uppe
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Java I/O tie, and a few similar cha
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Java I/O The most common type of ch
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Java I/O encoding into a new file c
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Java I/O String openingLineInUnicod
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Java I/O For example, given some Wr
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The flush() and close() methods flu
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15.4 The InputStreamReader Class Th
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Java I/O Similarly, to write text i
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Java I/O These methods behave like
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Java I/O Since string objects are i
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This class has three constructors t
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Do not use the newLine() method if
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Example 15.5. The cat Program impor
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There are four constructors in this
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PipedReader pr = new PipedReader();
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Example 15.7. SourceReader package
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Java I/O question is what to do if
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Java I/O numeric data. If they choo
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} public boolean isText() { if (thi
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default: } } else { LittleEndianInp
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public void init() { } this.addWind
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Chapter 16. Formatted I/O with java
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Java I/O variable salary 12 places
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Hebrew Hebrew Israel iw Hungarian R
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For example: Java I/O NumberFormat
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public void setMaximumIntegerDigits
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Java I/O Like other aspects of text
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Example 16.5. PercentTable import j
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Java I/O align the decimal points i
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Figure 16.1. The PrettiestTable app
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Java I/O This whole class is just a
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Java I/O Most number formats are in
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public int getMultiplier() public v
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Arabic (Saudi Arabia) Arabic (Sudan
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Slovak #,##0.### -1 234,56 #,##0.00
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16.6.2.1 Utility methods Java I/O F
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** * Concrete class for formatting
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} String integerField = digits.subs
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Chapter 17. The Java Communications
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javax.comm.CommPortIdentifier@be4c9
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} } } switch(com.getPortType()) { c
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Java I/O In this example, you see t
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17.2.5 Registering Ports For comple
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} public void run() { } try { byte[
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Java I/O The output buffer size is
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Java I/O Here's the results for bot
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Java I/O If the requested values ar
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Figure 17.1. PC DB-25 serial port t
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public abstract void setRTS(boolean
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Java I/O Steps 1 and 2 should be fa
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Java I/O standard messages on other
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Java I/O serial port events: when t
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17.5.5.3 Step 3 Java I/O In many ci
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Appendix A. Additional Resources Ja
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A.5 Data Compression Java I/O Java
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Java I/O "Developing International
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Appendix B. Character Sets Java I/O
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151 epa (end of guarded area) 183
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Java I/O Cp857 DOS ASCII plus Turki
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Java I/O As extensive as this list
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