1. 看下面源碼，找到%號，每次加2，然后將16進制轉換為int，也就是%號后兩位加2得到16進制，轉換為int
while ( ((i+2) < numChars) && (c=='%')) { int v = Integer.parseInt(s.substring(i+1,i+3),16); if (v < 0) throw new IllegalArgumentException("URLDecoder: Illegal hex characters in escape (%) pattern - negative value"); bytes[pos++] = (byte) v; i+= 3; if (i < numChars) c = s.charAt(i); }
這就是為什么url中不能有%號的原因，
2. 下面錯就有可能url中有特殊字符，比如 %
Note that the name and value quoted here may be corrupted due to the failed decoding. Use debug level logging to see the original, non-corrupted values.Note: further occurrences of Parameter errors will be logged at DEBUG level.
3. request.getParameter("Json");這個獲得的是 null，urldecode之后的，因為urldecode出錯了，所以會是null
4. request.getQueryString();這個得到的是，沒有urldecode的，也就是原始的
二、 關于看tomcat源碼的一些知識點，這是一個鏈接到達tomcat之后，要執(zhí)行的過程，為什么要總結呢，request.getParameter("Json");中，如果Json中有特殊符號，如%，服務器會的到null，就是因為urldecode導致，看了源碼什么都懂了
String an = request.getQueryString(); //獲取沒有被urldecode的參數值
String an = request.getParameter("Json"); //獲取被urldecode解碼后的參數值
1. org.apache.catalina.connector.Connector ，其中還有很多關于配置的在這個類中，自己看
public Connector(String protocol) { setProtocol(protocol); // Instantiate protocol handler try { Class<?> clazz = Class.forName(protocolHandlerClassName); this.protocolHandler = (ProtocolHandler) clazz.newInstance(); } catch (Exception e) { log.error(sm.getString( "coyoteConnector.protocolHandlerInstantiationFailed"), e); } }
構造函數中 protocol 對應 server.xml protocol="HTTP/1.1" 所以構造函數中的 protocol 值為 HTTP/1.1
<Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" maxHttpHeaderSize="1048576"/>
2. org.apache.catalina.connector.RequestFacade implements HttpServletRequest
public String getParameter(String name) { //不是這個方法，下面那個方法 if (request == null) { throw new IllegalStateException( sm.getString("requestFacade.nullRequest")); } if (Globals.IS_SECURITY_ENABLED){ return AccessController.doPrivileged( new GetParameterPrivilegedAction(name)); } else { return request.getParameter(name); } }
@Override public Map<String,String[]> getParameterMap() {//這個方法 if (request == null) { throw new IllegalStateException( sm.getString("requestFacade.nullRequest")); } if (Globals.IS_SECURITY_ENABLED){ return AccessController.doPrivileged( new GetParameterMapPrivilegedAction()); } else { return request.getParameterMap(); } }
public Map<String, String[]> getParameterMap() { if (parameterMap.isLocked()) { return parameterMap; } Enumeration<String> enumeration = getParameterNames(); while (enumeration.hasMoreElements()) { String name = enumeration.nextElement(); String[] values = getParameterValues(name); parameterMap.put(name, values); } parameterMap.setLocked(true); return parameterMap; }
public Enumeration<String> getParameterNames() { if (!parametersParsed) { parseParameters(); } return coyoteRequest.getParameters().getParameterNames(); }
3. org.apache.catalina.connector.Request implements HttpServletRequest
public String getParameter(String name) { if (!parametersParsed) { parseParameters(); } return coyoteRequest.getParameters().getParameter(name); }
4. org.apache.catalina.connector.Request implements HttpServletRequest
protected void parseParameters() { parametersParsed = true; Parameters parameters = coyoteRequest.getParameters(); boolean success = false; try { // Set this every time in case limit has been changed via JMX parameters.setLimit(getConnector().getMaxParameterCount()); //參數的數量最多為10000 // getCharacterEncoding() may have been overridden to search for // hidden form field containing request encoding String enc = getCharacterEncoding(); boolean useBodyEncodingForURI = connector.getUseBodyEncodingForURI(); if (enc != null) { parameters.setEncoding(enc); if (useBodyEncodingForURI) { parameters.setQueryStringEncoding(enc); } } else { parameters.setEncoding (org.apache.coyote.Constants.DEFAULT_CHARACTER_ENCODING); if (useBodyEncodingForURI) { parameters.setQueryStringEncoding (org.apache.coyote.Constants.DEFAULT_CHARACTER_ENCODING); } } parameters.handleQueryParameters(); if (usingInputStream || usingReader) { success = true; return; } if( !getConnector().isParseBodyMethod(getMethod()) ) { success = true; return; } String contentType = getContentType(); if (contentType == null) { contentType = ""; } int semicolon = contentType.indexOf(';'); if (semicolon >= 0) { contentType = contentType.substring(0, semicolon).trim(); } else { contentType = contentType.trim(); } if ("multipart/form-data".equals(contentType)) { parseParts(); success = true; return; } if (!("application/x-www-form-urlencoded".equals(contentType))) { success = true; return; } int len = getContentLength(); if (len > 0) { int maxPostSize = connector.getMaxPostSize(); if ((maxPostSize > 0) && (len > maxPostSize)) { if (context.getLogger().isDebugEnabled()) { context.getLogger().debug( sm.getString("coyoteRequest.postTooLarge")); } checkSwallowInput(); return; } byte[] formData = null; if (len < CACHED_POST_LEN) { if (postData == null) { postData = new byte[CACHED_POST_LEN]; } formData = postData; } else { formData = new byte[len]; } try { if (readPostBody(formData, len) != len) { return; } } catch (IOException e) { // Client disconnect if (context.getLogger().isDebugEnabled()) { context.getLogger().debug( sm.getString("coyoteRequest.parseParameters"), e); } return; } parameters.processParameters(formData, 0, len); } else if ("chunked".equalsIgnoreCase( coyoteRequest.getHeader("transfer-encoding"))) { byte[] formData = null; try { formData = readChunkedPostBody(); } catch (IOException e) { // Client disconnect or chunkedPostTooLarge error if (context.getLogger().isDebugEnabled()) { context.getLogger().debug( sm.getString("coyoteRequest.parseParameters"), e); } return; } if (formData != null) { parameters.processParameters(formData, 0, formData.length); } } success = true; } finally { if (!success) { parameters.setParseFailed(true); } } }
5. org.apache.tomcat.util.http.Parameters 中 processParameters
private void processParameters(byte bytes[], int start, int len, Charset charset) { if(log.isDebugEnabled()) { log.debug(sm.getString("parameters.bytes", new String(bytes, start, len, DEFAULT_CHARSET))); } int decodeFailCount = 0; int pos = start; int end = start + len; while(pos < end) { int nameStart = pos; int nameEnd = -1; int valueStart = -1; int valueEnd = -1; boolean parsingName = true; boolean decodeName = false; boolean decodeValue = false; boolean parameterComplete = false; do { switch(bytes[pos]) { case '=': if (parsingName) { // Name finished. Value starts from next character nameEnd = pos; parsingName = false; valueStart = ++pos; } else { // Equals character in value pos++; } break; case '&': if (parsingName) { // Name finished. No value. nameEnd = pos; } else { // Value finished valueEnd = pos; } parameterComplete = true; pos++; break; case '%': case '+': // Decoding required if (parsingName) { decodeName = true; } else { decodeValue = true; } pos ++; break; default: pos ++; break; } } while (!parameterComplete && pos < end); if (pos == end) { if (nameEnd == -1) { nameEnd = pos; } else if (valueStart > -1 && valueEnd == -1){ valueEnd = pos; } } if (log.isDebugEnabled() && valueStart == -1) { log.debug(sm.getString("parameters.noequal", Integer.valueOf(nameStart), Integer.valueOf(nameEnd), new String(bytes, nameStart, nameEnd-nameStart, DEFAULT_CHARSET))); } if (nameEnd <= nameStart ) { if (valueStart == -1) { // && if (log.isDebugEnabled()) { log.debug(sm.getString("parameters.emptyChunk")); } // Do not flag as error continue; } // &=foo& UserDataHelper.Mode logMode = userDataLog.getNextMode(); if (logMode != null) { String extract; if (valueEnd > nameStart) { extract = new String(bytes, nameStart, valueEnd - nameStart, DEFAULT_CHARSET); } else { extract = ""; } String message = sm.getString("parameters.invalidChunk", Integer.valueOf(nameStart), Integer.valueOf(valueEnd), extract); switch (logMode) { case INFO_THEN_DEBUG: message += sm.getString("parameters.fallToDebug"); //$FALL-THROUGH$ case INFO: log.info(message); break; case DEBUG: log.debug(message); } } parseFailed = true; continue; // invalid chunk - it's better to ignore } tmpName.setBytes(bytes, nameStart, nameEnd - nameStart); if (valueStart >= 0) { tmpValue.setBytes(bytes, valueStart, valueEnd - valueStart); } else { tmpValue.setBytes(bytes, 0, 0); } // Take copies as if anything goes wrong originals will be // corrupted. This means original values can be logged. // For performance - only done for debug if (log.isDebugEnabled()) { try { origName.append(bytes, nameStart, nameEnd - nameStart); if (valueStart >= 0) { origValue.append(bytes, valueStart, valueEnd - valueStart); } else { origValue.append(bytes, 0, 0); } } catch (IOException ioe) { // Should never happen... log.error(sm.getString("parameters.copyFail"), ioe); } } try { String name; String value; if (decodeName) { urlDecode(tmpName); } tmpName.setCharset(charset); name = tmpName.toString(); if (valueStart >= 0) { if (decodeValue) { urlDecode(tmpValue); } tmpValue.setCharset(charset); //ISO-8859-1 value = tmpValue.toString(); } else { value = ""; } try { addParameter(name, value); // 添加到參數集合中 } catch (IllegalStateException ise) { // Hitting limit stops processing further params but does // not cause request to fail. parseFailed = true; UserDataHelper.Mode logMode = maxParamCountLog.getNextMode(); if (logMode != null) { String message = ise.getMessage(); switch (logMode) { case INFO_THEN_DEBUG: message += sm.getString( "parameters.maxCountFail.fallToDebug"); //$FALL-THROUGH$ case INFO: log.info(message); break; case DEBUG: log.debug(message); } } break; } } catch (IOException e) { parseFailed = true; decodeFailCount++; if (decodeFailCount == 1 || log.isDebugEnabled()) { if (log.isDebugEnabled()) { log.debug(sm.getString("parameters.decodeFail.debug", origName.toString(), origValue.toString()), e); } else if (log.isInfoEnabled()) { UserDataHelper.Mode logMode = userDataLog.getNextMode(); if (logMode != null) { String message = sm.getString( "parameters.decodeFail.info", tmpName.toString(), tmpValue.toString()); switch (logMode) { case INFO_THEN_DEBUG: message += sm.getString("parameters.fallToDebug"); //$FALL-THROUGH$ case INFO: log.info(message); break; case DEBUG: log.debug(message); } } } } } tmpName.recycle(); tmpValue.recycle(); // Only recycle copies if we used them if (log.isDebugEnabled()) { origName.recycle(); origValue.recycle(); } } if (decodeFailCount > 1 && !log.isDebugEnabled()) { UserDataHelper.Mode logMode = userDataLog.getNextMode(); if (logMode != null) { String message = sm.getString( "parameters.multipleDecodingFail", Integer.valueOf(decodeFailCount)); switch (logMode) { case INFO_THEN_DEBUG: message += sm.getString("parameters.fallToDebug"); //$FALL-THROUGH$ case INFO: log.info(message); break; case DEBUG: log.debug(message); } } } }
6. org.apache.tomcat.util.buf.UDecoder
public final String convert(String str, boolean query) { if (str == null) { return null; } if( (!query || str.indexOf( '+' ) < 0) && str.indexOf( '%' ) < 0 ) { return str; } final boolean noSlash = !(ALLOW_ENCODED_SLASH || query); StringBuilder dec = new StringBuilder(); // decoded string output int strPos = 0; int strLen = str.length(); dec.ensureCapacity(str.length()); while (strPos < strLen) { int laPos; // lookahead position // look ahead to next URLencoded metacharacter, if any for (laPos = strPos; laPos < strLen; laPos++) { char laChar = str.charAt(laPos); if ((laChar == '+' && query) || (laChar == '%')) { break; } } // if there were non-metacharacters, copy them all as a block if (laPos > strPos) { dec.append(str.substring(strPos,laPos)); strPos = laPos; } // shortcut out of here if we're at the end of the string if (strPos >= strLen) { break; } // process next metacharacter char metaChar = str.charAt(strPos); if (metaChar == '+') { dec.append(' '); strPos++; continue; } else if (metaChar == '%') { // We throw the original exception - the super will deal with // it // try { char res = (char) Integer.parseInt( //得到%號后面兩個字符，之后以16進制轉換成int類型再轉換成char類型，之后追加到dec上 str.substring(strPos + 1, strPos + 3), 16); if (noSlash && (res == '/')) { throw new IllegalArgumentException("noSlash"); } dec.append(res); strPos += 3; } } return dec.toString(); }
