String data = "para="+URLEncoder.encode("参数"); outputStream.write(data.getBytes()); .......

package com.j2medev.httpme.tools;

import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.OutputStreamWriter; import java.io.UnsupportedEncodingException; /**  * Utility class for  form encoding.this class is modified form java.net.URLEncoder

so that it can work well in cldc env.  * 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:  *  * <p>  * <ul>  * <li>The alphanumeric characters "<code>a</code>" through  *     "<code>z</code>", "<code>A</code>" through  *     "<code>Z</code>" and "<code>0</code>"  *     through "<code>9</code>" remain the same.  * <li>The special characters "<code>.</code>",  *     "<code>-</code>", "<code>*</code>", and  *     "<code>_</code>" remain the same.  * <li>The space character "<code> </code>" is  *     converted into a plus sign "<code>+</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  *     "<code>%<i>xy</i></code>", 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).  *  */ public class URLEncoder {         /** The characters which do not need to be encoded. */     private static boolean[] dontNeedEncoding;     private static String defaultEncName = "";     static final int caseDiff = ('a' - 'A');     static {         dontNeedEncoding = new boolean[256];         int i;         for (i = 'a'; i <= 'z'; i++) {             dontNeedEncoding[i] = true;         }         for (i = 'A'; i <= 'Z'; i++) {             dontNeedEncoding[i] = true;         }         for (i = '0'; i <= '9'; i++) {             dontNeedEncoding[i] = true;         }         dontNeedEncoding[' '] = true; // encoding a space to a + is done

in the encode() method         dontNeedEncoding['-'] = true;         dontNeedEncoding['_'] = true;         dontNeedEncoding['.'] = true;         dontNeedEncoding['*'] = true;         defaultEncName = System.getProperty("microedition.encoding");         if(defaultEncName == null || defaultEncName.trim().length() == 0){             defaultEncName = "UTF-8";         }     }         public static final int MIN_RADIX = 2;         /**      * The maximum radix available for conversion to and from strings.      */     public static final int MAX_RADIX = 36;     /**      * The class is not meant to be instantiated.      */     private URLEncoder() { }

/**      * Translates a string into "<CODE>x-www-form-urlencoded</CODE>"      * format.This method uses the platform's default encoding      * as the encoding scheme to obtain the bytes for unsafe characters.      *      * @param  s the string to be translated.      *      * @return The resulting string.      */     public static String encode(String s) {         String str = null;         str = encode(s, defaultEncName);         return str;     }        /**      * 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 character encoding such as UTF-8      * @return  the translated <code>String</code>.      */     public static String encode(String s, String enc) {                 boolean needToChange = false;         boolean wroteUnencodedChar = false;         int maxBytesPerChar = 10; // rather arbitrary limit, but safe for now         StringBuffer out = new StringBuffer(s.length());         ByteArrayOutputStream buf = new ByteArrayOutputStream(maxBytesPerChar);         OutputStreamWriter writer = null;         try {             writer = new OutputStreamWriter(buf, enc);         } catch (UnsupportedEncodingException ex) {             try {                 writer = new OutputStreamWriter(buf,defaultEncName);             } catch (UnsupportedEncodingException e) {                 //never reach             }         }                 for (int i = 0; i < s.length(); i++) {             int c = (int) s.charAt(i);             //System.out.println("Examining character: " + c);             if (c <256 && dontNeedEncoding[c]) {                 if (c == ' ') {                     c = '+';                     needToChange = true;                 }                 //System.out.println("Storing: " + c);                 out.append((char)c);                 wroteUnencodedChar = true;             } else {                 // convert to external encoding before hex conversion                 try {                     if (wroteUnencodedChar) { // Fix for 4407610                         writer = new OutputStreamWriter(buf, enc);                         wroteUnencodedChar = false;                     }                     if(writer != null)                         writer.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");                                  */                                 writer.write(d);                                 i++;                             }                         }                     }                     writer.flush();                 } catch(IOException e) {                     buf.reset();                     continue;                 }                 byte[] ba = buf.toByteArray();                 for (int j = 0; j < ba.length; j++) {                     out.append('%');                     char ch = forDigit((ba[j] >> 4) & 0xF, 16);                     if (isLetter(ch)) {                         ch -= caseDiff;                  }                     out.append(ch);                                      ch = forDigit((ba[j] & 0xF), 16);                    //ch = forDigit(ba[j] & 0xF, 16);                     if (isLetter(ch)) {                         ch -= caseDiff;                     }                     out.append(ch);                 }                 buf.reset();                 needToChange = true;             }         }                 return (needToChange? out.toString() : s);     }         private static boolean isLetter(char c){         if( (c >= 'a' && c <= 'z') || (c >='A' && c <= 'Z'))             return true;         return false;     }         private static char forDigit(int digit,int radix){         if ((digit >= radix) || (digit < 0)) {             return '\0';        }         if ((radix < MIN_RADIX) || (radix > MAX_RADIX)) {             return '\0';         }         if (digit < 10) {             return (char)('0' + digit);         }         return (char)('a' - 10 + digit);     } }