/*
* Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*
*
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*
*
*
*
*
*
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*
*/
package java.net;
import java.io.
ByteArrayOutputStream;
import java.io.
BufferedWriter;
import java.io.
OutputStreamWriter;
import java.io.
IOException;
import java.io.
UnsupportedEncodingException;
import java.io.
CharArrayWriter;
import java.nio.charset.
Charset;
import java.nio.charset.
IllegalCharsetNameException;
import java.nio.charset.
UnsupportedCharsetException ;
import java.util.
BitSet;
import java.security.
AccessController;
import java.security.
PrivilegedAction;
import sun.security.action.
GetBooleanAction;
import sun.security.action.
GetPropertyAction;
/**
* Utility class for HTML form encoding. This class contains static methods
* for converting a String to the <CODE>application/x-www-form-urlencoded</CODE> MIME
* format. For more information about HTML form encoding, consult the HTML
* <A HREF="http://www.w3.org/TR/html4/">specification</A>.
*
* <p>
* When encoding a String, the following rules apply:
*
* <ul>
* <li>The alphanumeric characters "{@code a}" through
* "{@code z}", "{@code A}" through
* "{@code Z}" and "{@code 0}"
* through "{@code 9}" remain the same.
* <li>The special characters "{@code .}",
* "{@code -}", "{@code *}", and
* "{@code _}" remain the same.
* <li>The space character " " is
* converted into a plus sign "{@code +}".
* <li>All other characters are unsafe and are first converted into
* one or more bytes using some encoding scheme. Then each byte is
* represented by the 3-character string
* "<i>{@code %xy}</i>", where <i>xy</i> is the
* two-digit hexadecimal representation of the byte.
* The recommended encoding scheme to use is UTF-8. However,
* for compatibility reasons, if an encoding is not specified,
* then the default encoding of the platform is used.
* </ul>
*
* <p>
* For example using UTF-8 as the encoding scheme the string "The
* string ü@foo-bar" would get converted to
* "The+string+%C3%BC%40foo-bar" because in UTF-8 the character
* ü is encoded as two bytes C3 (hex) and BC (hex), and the
* character @ is encoded as one byte 40 (hex).
*
* @author Herb Jellinek
* @since JDK1.0
*/
public class
URLEncoder {
static
BitSet dontNeedEncoding;
static final int
caseDiff = ('a' - 'A');
static
String dfltEncName = null;
static {
/* The list of characters that are not encoded has been
* determined as follows:
*
* RFC 2396 states:
* -----
* Data characters that are allowed in a URI but do not have a
* reserved purpose are called unreserved. These include upper
* and lower case letters, decimal digits, and a limited set of
* punctuation marks and symbols.
*
* unreserved = alphanum | mark
*
* mark = "-" | "_" | "." | "!" | "~" | "*" | "'" | "(" | ")"
*
* Unreserved characters can be escaped without changing the
* semantics of the URI, but this should not be done unless the
* URI is being used in a context that does not allow the
* unescaped character to appear.
* -----
*
* It appears that both Netscape and Internet Explorer escape
* all special characters from this list with the exception
* of "-", "_", ".", "*". While it is not clear why they are
* escaping the other characters, perhaps it is safest to
* assume that there might be contexts in which the others
* are unsafe if not escaped. Therefore, we will use the same
* list. It is also noteworthy that this is consistent with
* O'Reilly's "HTML: The Definitive Guide" (page 164).
*
* As a last note, Intenet Explorer does not encode the "@"
* character which is clearly not unreserved according to the
* RFC. We are being consistent with the RFC in this matter,
* as is Netscape.
*
*/
dontNeedEncoding = new
BitSet(256);
int
i;
for (
i = 'a';
i <= 'z';
i++) {
dontNeedEncoding.
set(
i);
}
for (
i = 'A';
i <= 'Z';
i++) {
dontNeedEncoding.
set(
i);
}
for (
i = '0';
i <= '9';
i++) {
dontNeedEncoding.
set(
i);
}
dontNeedEncoding.
set(' '); /* encoding a space to a + is done
* in the encode() method */
dontNeedEncoding.
set('-');
dontNeedEncoding.
set('_');
dontNeedEncoding.
set('.');
dontNeedEncoding.
set('*');
dfltEncName =
AccessController.
doPrivileged(
new
GetPropertyAction("file.encoding")
);
}
/**
* You can't call the constructor.
*/
private
URLEncoder() { }
/**
* Translates a string into {@code x-www-form-urlencoded}
* format. This method uses the platform's default encoding
* as the encoding scheme to obtain the bytes for unsafe characters.
*
* @param s {@code String} to be translated.
* @deprecated The resulting string may vary depending on the platform's
* default encoding. Instead, use the encode(String,String)
* method to specify the encoding.
* @return the translated {@code String}.
*/
@
Deprecated
public static
String encode(
String s) {
String str = null;
try {
str =
encode(
s,
dfltEncName);
} catch (
UnsupportedEncodingException e) {
// The system should always have the platform default
}
return
str;
}
/**
* Translates a string into {@code application/x-www-form-urlencoded}
* format using a specific encoding scheme. This method uses the
* supplied encoding scheme to obtain the bytes for unsafe
* characters.
* <p>
* <em><strong>Note:</strong> The <a href=
* "http://www.w3.org/TR/html40/appendix/notes.html#non-ascii-chars">
* World Wide Web Consortium Recommendation</a> states that
* UTF-8 should be used. Not doing so may introduce
* incompatibilities.</em>
*
* @param s {@code String} to be translated.
* @param enc The name of a supported
* <a href="../lang/package-summary.html#charenc">character
* encoding</a>.
* @return the translated {@code String}.
* @exception UnsupportedEncodingException
* If the named encoding is not supported
* @see URLDecoder#decode(java.lang.String, java.lang.String)
* @since 1.4
*/
public static
String encode(
String s,
String enc)
throws
UnsupportedEncodingException {
boolean
needToChange = false;
StringBuffer out = new
StringBuffer(
s.
length());
Charset charset;
CharArrayWriter charArrayWriter = new
CharArrayWriter();
if (
enc == null)
throw new
NullPointerException("charsetName");
try {
charset =
Charset.
forName(
enc);
} catch (
IllegalCharsetNameException e) {
throw new
UnsupportedEncodingException(
enc);
} catch (
UnsupportedCharsetException e) {
throw new
UnsupportedEncodingException(
enc);
}
for (int
i = 0;
i <
s.
length();) {
int
c = (int)
s.
charAt(
i);
//System.out.println("Examining character: " + c);
if (
dontNeedEncoding.
get(
c)) {
if (
c == ' ') {
c = '+';
needToChange = true;
}
//System.out.println("Storing: " + c);
out.
append((char)
c);
i++;
} else {
// convert to external encoding before hex conversion
do {
charArrayWriter.
write(
c);
/*
* If this character represents the start of a Unicode
* surrogate pair, then pass in two characters. It's not
* clear what should be done if a bytes reserved in the
* surrogate pairs range occurs outside of a legal
* surrogate pair. For now, just treat it as if it were
* any other character.
*/
if (
c >= 0xD800 &&
c <= 0xDBFF) {
/*
System.out.println(Integer.toHexString(c)
+ " is high surrogate");
*/
if ( (
i+1) <
s.
length()) {
int
d = (int)
s.
charAt(
i+1);
/*
System.out.println("\tExamining "
+ Integer.toHexString(d));
*/
if (
d >= 0xDC00 &&
d <= 0xDFFF) {
/*
System.out.println("\t"
+ Integer.toHexString(d)
+ " is low surrogate");
*/
charArrayWriter.
write(
d);
i++;
}
}
}
i++;
} while (
i <
s.
length() && !
dontNeedEncoding.
get((
c = (int)
s.
charAt(
i))));
charArrayWriter.
flush();
String str = new
String(
charArrayWriter.
toCharArray());
byte[]
ba =
str.
getBytes(
charset);
for (int
j = 0;
j <
ba.length;
j++) {
out.
append('%');
char
ch =
Character.
forDigit((
ba[
j] >> 4) & 0xF, 16);
// converting to use uppercase letter as part of
// the hex value if ch is a letter.
if (
Character.
isLetter(
ch)) {
ch -=
caseDiff;
}
out.
append(
ch);
ch =
Character.
forDigit(
ba[
j] & 0xF, 16);
if (
Character.
isLetter(
ch)) {
ch -=
caseDiff;
}
out.
append(
ch);
}
charArrayWriter.
reset();
needToChange = true;
}
}
return (
needToChange?
out.
toString() :
s);
}
}