JAVA 상용 클래스 (IO 편) - Data Output Stream 상세 설명
22252 단어 io
package java.io;
/**
* DataOutputStream java .
*/
public
class DataOutputStream extends FilterOutputStream implements DataOutput {
/**
* byte
* counter ， Integer.MAX_VALUE
*/
protected int written;
/**
* bytearr writeUTF
*/
private byte[] bytearr = null;
/**
* data output stream output stream ，
* counter 0
*
* @param out output strean，
* @see java.io.FilterOutputStream#out
*/
public DataOutputStream(OutputStream out) {
super(out);
}
/**
* written value， Integer.MAX_VALUE，written *Integer.MAX_VALUE
*/
private void incCount(int value) {
int temp = written + value;
if (temp < 0) {
temp = Integer.MAX_VALUE;
}
written = temp;
}
/**
* byte ( b 8 int ) output stream . , written 1
*
* OutputStram write
*
* @param b byte
* @exception I/O I/O
* @see java.io.FilterOutputStream#out
*/
public synchronized void write(int b) throws IOException {
out.write(b);
incCount(1);
}
/**
* byte len byte output stream ， byte offset。 written len
*
* @param b byte
* @param off .
* @param len byte .
* @exception I/O I/O
* @see java.io.FilterOutputStream#out
*/
public synchronized void write(byte b[], int off, int len)
throws IOException
{
out.write(b, off, len);
incCount(len);
}
/**
* output stream， output stream
*
* DataOutputStream flush output stream flush
* @exception I/O I/O
* @see java.io.FilterOutputStream#out
* @see java.io.OutputStream#flush()
*/
public void flush() throws IOException {
out.flush();
}
/**
* output stream bool（ 1 ）， v true 1，false 0。 written 1
*
* @param v bool
* @exception I/O I/O
* @see java.io.FilterOutputStream#out
*/
public final void writeBoolean(boolean v) throws IOException {
out.write(v ? 1 : 0);
incCount(1);
}
/**
* output stream byte。 written 1
*
* @param v
* @exception I/O I/O
* @see java.io.FilterOutputStream#out
*/
public final void writeByte(int v) throws IOException {
out.write(v);
incCount(1);
}
/**
* output stream 2 byte（1 short）。 written 2
*
* @param v short
* @exception I/O I/O .
* @see java.io.FilterOutputStream#out
*/
public final void writeShort(int v) throws IOException {
out.write((v >>> 8) & 0xFF);
out.write((v >>> 0) & 0xFF);
incCount(2);
}
/**
* char(2 byte), . written 2.
*
* @param v char
* @exception I/O I/O .
* @see java.io.FilterOutputStream#out
*/
public final void writeChar(int v) throws IOException {
out.write((v >>> 8) & 0xFF);
out.write((v >>> 0) & 0xFF);
incCount(2);
}
/**
* int(4 byte), . written 4.
* @param v int
* @exception I/O I/O .
* @see java.io.FilterOutputStream#out
*/
public final void writeInt(int v) throws IOException {
out.write((v >>> 24) & 0xFF);
out.write((v >>> 16) & 0xFF);
out.write((v >>> 8) & 0xFF);
out.write((v >>> 0) & 0xFF);
incCount(4);
}
private byte writeBuffer[] = new byte[8];
/**
* long(8 byte), . written 8.
*
* @param v a long to be written.
* @exception IOException if an I/O error occurs.
* @see java.io.FilterOutputStream#out
*/
public final void writeLong(long v) throws IOException {
writeBuffer[0] = (byte)(v >>> 56);
writeBuffer[1] = (byte)(v >>> 48);
writeBuffer[2] = (byte)(v >>> 40);
writeBuffer[3] = (byte)(v >>> 32);
writeBuffer[4] = (byte)(v >>> 24);
writeBuffer[5] = (byte)(v >>> 16);
writeBuffer[6] = (byte)(v >>> 8);
writeBuffer[7] = (byte)(v >>> 0);
out.write(writeBuffer, 0, 8);
incCount(8);
}
/**
* Float floatToIntBits float int， int output stream（ 4 byte ）， written 4.
* @param v float
* @exception I/O I/O
* @see java.io.FilterOutputStream#out
* @see java.lang.Float#floatToIntBits(float)
*/
public final void writeFloat(float v) throws IOException {
writeInt(Float.floatToIntBits(v));
}
/**
* Double doubleToLongBits float double， double output stream（ 8 byte ）， written 8.
* @param v double
* @exception I/O I/O .
* @see java.io.FilterOutputStream#out
* @see java.lang.Double#doubleToLongBits(double)
*/
public final void writeDouble(double v) throws IOException {
writeLong(Double.doubleToLongBits(v));
}
/**
* bytes output stream 。 ， 8 bit。 written s
*
* @param s
* @exception I/O I/O .
* @see java.io.FilterOutputStream#out
*/
public final void writeBytes(String s) throws IOException {
int len = s.length();
for (int i = 0 ; i < len ; i++) {
out.write((byte)s.charAt(i));
}
incCount(len);
}
/**
* Writes a string to the underlying output stream as a sequence of
* characters
* output stream . writeChar output stream . written s
*
* @param s
* @exception IOException I/O I/O .
* @see java.io.DataOutputStream#writeChar(int)
* @see java.io.FilterOutputStream#out
*/
public final void writeChars(String s) throws IOException {
int len = s.length();
for (int i = 0 ; i < len ; i++) {
int v = s.charAt(i);
out.write((v >>> 8) & 0xFF);
out.write((v >>> 0) & 0xFF);
}
incCount(len * 2);
}
/**
*
UTF-8 ， DataOutput ，2byte writeShort ， byte 。 byte ， string ， ， output， ， UTF-8 。 ， written output stream byte ， ， 。
*
* @param str a string to be written.
* @exception IOException if an I/O error occurs.
*/
public final void writeUTF(String str) throws IOException {
writeUTF(str, this);
}
/**
* UTF-8 ， DataOutput ，2byte writeShort ， byte 。 byte ， string ， ， output， ， UTF-8 。 ， written output stream byte ， ， 。
* @param str
* @param out
* @return byte
* @exception IOException I/O
*/
static int writeUTF(String str, DataOutput out) throws IOException {
int strlen = str.length();
int utflen = 0;
int c, count = 0;
/* use charAt instead of copying String to char array */
for (int i = 0; i < strlen; i++) {
c = str.charAt(i);
if ((c >= 0x0001) && (c <= 0x007F)) {
utflen++;
} else if (c > 0x07FF) {
utflen += 3;
} else {
utflen += 2;
}
}
if (utflen > 65535)
throw new UTFDataFormatException(
"encoded string too long: " + utflen + " bytes");
byte[] bytearr = null;
if (out instanceof DataOutputStream) {
DataOutputStream dos = (DataOutputStream)out;
if(dos.bytearr == null || (dos.bytearr.length < (utflen+2)))
dos.bytearr = new byte[(utflen*2) + 2];
bytearr = dos.bytearr;
} else {
bytearr = new byte[utflen+2];
}
bytearr[count++] = (byte) ((utflen >>> 8) & 0xFF);
bytearr[count++] = (byte) ((utflen >>> 0) & 0xFF);
int i=0;
for (i=0; iif (!((c >= 0x0001) && (c <= 0x007F))) break;
bytearr[count++] = (byte) c;
}
for (;i < strlen; i++){
c = str.charAt(i);
if ((c >= 0x0001) && (c <= 0x007F)) {
bytearr[count++] = (byte) c;
} else if (c > 0x07FF) {
bytearr[count++] = (byte) (0xE0 | ((c >> 12) & 0x0F));
bytearr[count++] = (byte) (0x80 | ((c >> 6) & 0x3F));
bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F));
} else {
bytearr[count++] = (byte) (0xC0 | ((c >> 6) & 0x1F));
bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F));
}
}
out.write(bytearr, 0, utflen+2);
return utflen + 2;
}
/**
* written ， output stream .
* ， Integer.MAX_VALUE.
*
* @return written
* @see java.io.DataOutputStream#written
*/
public final int size() {
return written;
}
}
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