Java IO.pdf - Nguyen Dang Binh

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11.5.1.5 Making nonserializable fields transient Java I/O Once you've identified the problem object, the simplest solution to is to mark the field that contains the object transient. For example, we can mark the Socket field transient in our networking applet: import java.applet.*; import java.net.*; public class MyNetworkingApplet extends Applet { } transient Socket theConnection; //... The transient keyword tells the writeObject() method not to serialize the Socket object theConnection onto the underlying output stream. Instead, it's just skipped. When the object is deserialized, you may need to ensure that the state is consistent with what you expect. You'll learn how to do this in Section 11.8. It may be enough to make sure theConnection is non-null before accessing it. 11.6 The ObjectInput and ObjectOutput Interfaces As well as the ObjectInputStream and ObjectOutputStream classes, the java.io package also provides ObjectInput and ObjectOutput interfaces: public interface ObjectInput extends DataInput public interface ObjectOutput extends DataOutput These interfaces are not much used in Java 1.1 and 2. The only classes in the core API that actually implement them are ObjectInputStream and ObjectOutputStream. However, several methods used for customization of the serialization process are declared to accept ObjectInput or ObjectOutput objects as arguments, rather than specifically ObjectInputStream or ObjectOutputStream objects. This provides a little wiggle room for Java to grow in unforeseen ways. The ObjectInput interface declares seven methods, all of which ObjectInputStream faithfully implements: public abstract Object readObject() throws ClassNotFoundException, IOException public abstract int read() throws IOException public abstract int read(byte[] data) throws IOException public abstract int read(byte[] data, int offset, int length) throws IOException public abstract long skip(long n) throws IOException public abstract int available() throws IOException public abstract void close() throws IOException The readObject() method has already been discussed in the context of object input streams. The other six methods behave exactly as they do for all input streams. In fact, at first glance, all these methods except readObject() appear superfluous, since any InputStream subclass will possess read(), skip(), available(), and close() methods with these signatures. 247
Java I/O However, this interface may be implemented by classes that aren't subclasses of InputStream. The ObjectOutput interface declares the following six methods, all of which ObjectOutputStream faithfully implements. Except for writeObject(), which has already been discussed in the context of object output streams, these methods should behave exactly as they do for all output streams: public abstract void writeObject(Object o) throws IOException public abstract void write(int b) throws IOException public abstract void write(byte data[]) throws IOException public abstract void write(byte[] data, int offset, int length) throws IOException public abstract void flush() throws IOException public abstract void close() throws IOException ObjectInput and ObjectOutput extend DataInput and DataOutput. Thus, as well as the methods declared outright, classes that implement ObjectInput must provide these additional methods as well: public abstract void readFully(byte data[]) throws IOException public abstract void readFully(byte data[], int offset, int length) throws IOException public abstract int skipBytes(int n) throws IOException public abstract boolean readBoolean() throws IOException public abstract byte readByte() throws IOException public abstract int readUnsignedByte() throws IOException public abstract short readShort() throws IOException public abstract int readUnsignedShort() throws IOException public abstract char readChar() throws IOException public abstract int readInt() throws IOException public abstract long readLong() throws IOException public abstract float readFloat() throws IOException public abstract double readDouble() throws IOException public abstract String readLine() throws IOException public abstract String readUTF() throws IOException Classes that implement ObjectOutput must provide these additional methods: public abstract void write(int b) throws IOException public abstract void write(byte[] data) throws IOException public abstract void write(byte[] data, int offset, int length) throws IOException public abstract void writeBoolean(boolean v) throws IOException public abstract void writeByte(int b) throws IOException public abstract void writeShort(int s) throws IOException public abstract void writeChar(int c) throws IOException public abstract void writeInt(int i) throws IOException public abstract void writeLong(long l) throws IOException public abstract void writeFloat(float f) throws IOException public abstract void writeDouble(double d) throws IOException public abstract void writeBytes(String s) throws IOException public abstract void writeChars(String s) throws IOException public abstract void writeUTF(String s) throws IOException As I noted back in Chapter 7, there's a bit of asymmetry between the DataInput and DataOutput interfaces. DataOutput declares the three write() methods you expect to find in 248
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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
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Chapter 10. Cryptographic Streams J
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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 250 and 251: Java I/O java.awt.image.renderable
Page 252 and 253: Java I/O are not serializable, then
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
Page 300 and 301: fin.close(); src.delete(); Java I/O
Page 302 and 303: 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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