Android 编码URL中文字符串

96
作者 孙鹏SIMPLE
2016.01.04 15:45* 字数 1090

如果 url 包含中文,浏览器是会自动编码解析的,但是在客户端开发会遇到中文编码问题,所以必须做中文编码。提供三种中文编码方式,仅供开发参考。

方案1:对源码进行修改,安全可靠

package com.gwsoft.imusic.o2ting.util;

import java.io.CharArrayWriter;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
import java.util.BitSet;

public class URLEncoderURI {

    static BitSet dontNeedEncoding;
    static final int caseDiff = ('a' - 'A');


    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('*');
        dontNeedEncoding.set(':');
        dontNeedEncoding.set('/');
        dontNeedEncoding.set('?');
        dontNeedEncoding.set(';');
        dontNeedEncoding.set('&');
        dontNeedEncoding.set('=');

    }

    /**
     * You can't call the constructor.
     */
    private URLEncoderURI() {
    }



    /**
     * Translates a string into <code>application/x-www-form-urlencoded</code>
     * 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
     * incompatibilites.</em>
     * 
     * @param s
     *            <code>String</code> 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</code>.
     * @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);
    }
}

用法:URLEncoderURI.encode(url, "UTF-8");

方案2:使用正则表达式

    public static String encodeUrl(String url) {
        return Uri.encode(url, "-![.:/,%?&=]");
    }

方案3:直接遍历url

参考:java中url汉字编码互相转换实例

    public static String toUtf8String(String s) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c >= 0 && c <= 255) {
                sb.append(c);
            } else {
                byte[] b;
                try {
                    b = String.valueOf(c).getBytes("utf-8");
                } catch (Exception ex) {
                    System.out.println(ex);
                    b = new byte[0];
                }
                for (int j = 0; j < b.length; j++) {
                    int k = b[j];
                    if (k < 0)
                        k += 256;
                    sb.append("%" + Integer.toHexString(k).toUpperCase());
                }
            }
        }
        return sb.toString();
    }
Android