tomcat中解析url中的参数或者post中的请求内容

package javax.servlet.http;import javax.servlet.ServletInputStream;import java.util.Hashtable;import java.util.ResourceBundle;import java.util.StringTokenizer;import java.io.IOException;/** * @deprecatedAs of Java(tm) Servlet API 2.3.  *These methods were only useful *with the default encoding and have been moved *to the request interfaces. **/public class HttpUtils {    private static final String LSTRING_FILE ="javax.servlet.http.LocalStrings";    private static ResourceBundle lStrings =ResourceBundle.getBundle(LSTRING_FILE);       /**     * Constructs an empty <code>HttpUtils</code> object.     *     */    public HttpUtils() {}    /**     *     * Parses a query string passed from the client to the     * server and builds a <code>HashTable</code> object     * with key-value pairs.      * The query string should be in the form of a string     * packaged by the GET or POST method, that is, it     * should have key-value pairs in the form <i>key=value</i>,     * with each pair separated from the next by a & character.     *     * <p>A key can appear more than once in the query string     * with different values. However, the key appears only once in      * the hashtable, with its value being     * an array of strings containing the multiple values sent     * by the query string.     *      * <p>The keys and values in the hashtable are stored in their     * decoded form, so任何加号被转换成空格,以16进制符号发送的字符(如%xx)被转换成ascii码     * any + characters are converted to spaces, and characters     * sent in hexadecimal notation (like <i>%xx</i>) are     * converted to ASCII characters.     *     * @param sa string containing the query to be parsed     *     * @returna <code>HashTable</code> object built     * from the parsed key-value pairs     *     * @exception IllegalArgumentExceptionif the query string      *is invalid     *  解析url中的参数,比如  http://www.baidu.com/s?word=JFinal架构&tn=93153871_hao_pg&ie=utf-8     *  word=JFinal架构       tn=93153871_hao_pg     ie=utf-8     */        static public Hashtable parseQueryString(String s) {String valArray[] = null;if (s == null) {    throw new IllegalArgumentException();}//这里用Hashtable,而不用Hashmap,是因为同一个key,可能会有多个value,而Hashmap只能存放一个value Hashtable ht = new Hashtable(); StringBuffer sb = new StringBuffer();StringTokenizer st = new StringTokenizer(s, "&");while (st.hasMoreTokens()) {    String pair = (String)st.nextToken();    int pos = pair.indexOf('=');    if (pos == -1) {// XXX// should give more detail about the illegal argumentthrow new IllegalArgumentException();    }    //解析key和value    String key = parseName(pair.substring(0, pos), sb);    String val = parseName(pair.substring(pos+1, pair.length()), sb);    if (ht.containsKey(key)) {//已经有此关键字名称了,多一个值String oldVals[] = (String []) ht.get(key);valArray = new String[oldVals.length + 1];for (int i = 0; i < oldVals.length; i++)     valArray[i] = oldVals[i];valArray[oldVals.length] = val;    }     else {valArray = new String[1];valArray[0] = val;    }    ht.put(key, valArray);}return ht;    }    /**     *     * Parses data from an HTML form that the client sends to      * the server using the HTTP POST method and the      * <i>application/x-www-form-urlencoded</i> MIME type.     *     * <p>The data sent by the POST method contains key-value     * pairs. A key can appear more than once in the POST data     * with different values. However, the key appears only once in      * the hashtable, with its value being     * an array of strings containing the multiple values sent     * by the POST method.     *     * <p>The keys and values in the hashtable are stored in their     * decoded form, so     * any + characters are converted to spaces, and characters     * sent in hexadecimal notation (like <i>%xx</i>) are     * converted to ASCII characters.     *     *     *     * @param lenan integer specifying the length,     *in characters, of the      *<code>ServletInputStream</code>     *object that is also passed to this     *method     *     * @param inthe <code>ServletInputStream</code>     *object that contains the data sent     *from the client     *      * @returna <code>HashTable</code> object built     *from the parsed key-value pairs     *     *     * @exception IllegalArgumentExceptionif the data     *sent by the POST method is invalid     *     */     static public Hashtable parsePostData(int len,   ServletInputStream in)    {// XXX// should a length of 0 be an IllegalArgumentExceptionif (len <=0)    return new Hashtable(); // cheap hack to return an empty hashif (in == null) {    throw new IllegalArgumentException();}//// Make sure we read the entire POSTed body.//        byte[] postedBytes = new byte [len];        try {            int offset = 0;           do {int inputLen = in.read (postedBytes, offset, len - offset);if (inputLen <= 0) {    String msg = lStrings.getString("err.io.short_read");    throw new IllegalArgumentException (msg);}offset += inputLen;    } while ((len - offset) > 0);} catch (IOException e) {    throw new IllegalArgumentException(e.getMessage());}        // XXX we shouldn't assume that the only kind of POST body        // is FORM data encoded using ASCII or ISO Latin/1 ... or        // that the body should always be treated as FORM data.        //        try {            String postedBody = new String(postedBytes, 0, len, "8859_1");            return parseQueryString(postedBody);        } catch (java.io.UnsupportedEncodingException e) {            // XXX function should accept an encoding parameter & throw this            // exception.  Otherwise throw something expected.            throw new IllegalArgumentException(e.getMessage());        }    }    /*     * Parse a name in the query string.     */    static private String parseName(String s, StringBuffer sb) {sb.setLength(0);for (int i = 0; i < s.length(); i++) {    char c = s.charAt(i);     switch (c) {    case '+'://加号转换成空格    sb.append(' ');    break;    case '%'://%xx后面的 16进制xx 转换成 10进制的数字,然后再转换成char型(即ascii码)try {    sb.append((char) Integer.parseInt(s.substring(i+1, i+3),       16));    i += 2;} catch (NumberFormatException e) {    // XXX    // need to be more specific about illegal arg    throw new IllegalArgumentException();} catch (StringIndexOutOfBoundsException e) {    String rest  = s.substring(i);    sb.append(rest);    if (rest.length()==2)i++;}break;    default:sb.append(c);break;    }}return sb.toString();    }       /**     *     * Reconstructs the URL the client used to make the request,     * using information in the <code>HttpServletRequest</code> object.     * The returned URL contains a protocol, server name, port     * number, and server path, but it does not include query     * string parameters.     *      * <p>Because this method returns a <code>StringBuffer</code>,     * not a string, you can modify the URL easily, for example,     * to append query parameters.     *     * <p>This method is useful for creating redirect messages     * and for reporting errors.     * 这个方法对创建重定向信息和报告错误非常有用     * @param reqa <code>HttpServletRequest</code> object     *containing the client's request     *      * @returna <code>StringBuffer</code> object containing     *the reconstructed URL     *     */    public static StringBuffer getRequestURL (HttpServletRequest req) {    StringBuffer url = new StringBuffer ();String scheme = req.getScheme ();int port = req.getServerPort ();String urlPath = req.getRequestURI();//StringservletPath = req.getServletPath ();//StringpathInfo = req.getPathInfo ();url.append (scheme);// http, httpsurl.append ("://");url.append (req.getServerName ());if ((scheme.equals ("http") && port != 80)|| (scheme.equals ("https") && port != 443)) {    url.append (':');    url.append (req.getServerPort ());}//if (servletPath != null)//    url.append (servletPath);//if (pathInfo != null)//    url.append (pathInfo);url.append(urlPath);return url;    }}