JDK都要出12了，而我们项目使用的jdk却仍然还停留在JDK1.6。为了追寻技术的发展的脚步，我这边准备将项目升级到JDK1.8。而作为一个web项目，我们的容器使用的是Tomcat。看了下Tomcat版本与JDK版本之间的兼容关系以及网上所传的各种JDK1.8和Tomcat7不兼容的问题， 我决定将Tomcat升级到8。我这里本地验证采用的tomcat版本是8.5.38 https://tomcat.apache.org/download-80.cgi。
问题一：请求js文件报404错误其实这个问题严格来讲不是升级到Tomcat8出现的问题，而是升级到Tomcat9出现的问题。正好我开始尝试的是Tomcat9，无法解决这个问题才降到Tomcat8。所以这里一并记录下来。
这个问题在从Tomcat6升级到Tomcat7之后也会存在，原因如下，在项目代码中对js的请求路径中包含了{、}等特殊符号：
<script type="text/javascript" src="${ctx}/js/common/include_css.js?{'ctx':'${ctx}','easyui':'easyui'}"></script>前台会发现加载js的时候报了404的错误，后台报错信息如下：
Invalid character found in the request target.The valid characters are defined in RFC 7230 and RFC3986出现这个问题的原因是因为Tomcat升级之后对安全进行了升级，其中就有对请求中的特殊字符进行校验，具体校验规则参照下面的代码：
(InternalInputBuffer、InternalAprInputBuffer、InternalNioInputBuffer)
/** * Read the request line. This function is meant to be used during the * HTTP request header parsing. Do NOT attempt to read the request body * using it. * * @throws IOException If an exception occurs during the underlying socket * read operations, or if the given buffer is not big enough to accommodate * the whole line. */ @Override public boolean parseRequestLine(boolean useAvailableDataOnly) throws IOException { int start = 0; // // Skipping blank lines // byte chr = 0; do { // Read new bytes if needed if (pos >= lastValid) { if (!fill()) throw new EOFException(sm.getString("iib.eof.error")); } // Set the start time once we start reading data (even if it is // just skipping blank lines) if (request.getStartTime() < 0) { request.setStartTime(System.currentTimeMillis()); } chr = buf[pos++]; } while ((chr == Constants.CR) || (chr == Constants.LF)); pos--; // Mark the current buffer position start = pos; // // Reading the method name // Method name is a token // boolean space = false; while (!space) { // Read new bytes if needed if (pos >= lastValid) { if (!fill()) throw new EOFException(sm.getString("iib.eof.error")); } // Spec says method name is a token followed by a single SP but // also be tolerant of multiple SP and/or HT. if (buf[pos] == Constants.SP || buf[pos] == Constants.HT) { space = true; request.method().setBytes(buf, start, pos - start); } else if (!HttpParser.isToken(buf[pos])) { throw new IllegalArgumentException(sm.getString("iib.invalidmethod")); } pos++; } // Spec says single SP but also be tolerant of multiple SP and/or HT while (space) { // Read new bytes if needed if (pos >= lastValid) { if (!fill()) throw new EOFException(sm.getString("iib.eof.error")); } if (buf[pos] == Constants.SP || buf[pos] == Constants.HT) { pos++; } else { space = false; } } // Mark the current buffer position start = pos; int end = 0; int questionPos = -1; // // Reading the URI // boolean eol = false; while (!space) { // Read new bytes if needed if (pos >= lastValid) { if (!fill()) throw new EOFException(sm.getString("iib.eof.error")); } // Spec says single SP but it also says be tolerant of HT if (buf[pos] == Constants.SP || buf[pos] == Constants.HT) { space = true; end = pos; } else if ((buf[pos] == Constants.CR) || (buf[pos] == Constants.LF)) { // HTTP/0.9 style request eol = true; space = true; end = pos; } else if ((buf[pos] == Constants.QUESTION) && (questionPos == -1)) { questionPos = pos; } else if (HttpParser.isNotRequestTarget(buf[pos])) { throw new IllegalArgumentException(sm.getString("iib.invalidRequestTarget")); } pos++; } request.unparsedURI().setBytes(buf, start, end - start); if (questionPos >= 0) { request.queryString().setBytes(buf, questionPos + 1, end - questionPos - 1); request.requestURI().setBytes(buf, start, questionPos - start); } else { request.requestURI().setBytes(buf, start, end - start); } // Spec says single SP but also says be tolerant of multiple SP and/or HT while (space) { // Read new bytes if needed if (pos >= lastValid) { if (!fill()) throw new EOFException(sm.getString("iib.eof.error")); } if (buf[pos] == Constants.SP || buf[pos] == Constants.HT) { pos++; } else { space = false; } } // Mark the current buffer position start = pos; end = 0; // // Reading the protocol // Protocol is always "HTTP/" DIGIT "." DIGIT // while (!eol) { // Read new bytes if needed if (pos >= lastValid) { if (!fill()) throw new EOFException(sm.getString("iib.eof.error")); } if (buf[pos] == Constants.CR) { end = pos; } else if (buf[pos] == Constants.LF) { if (end == 0) end = pos; eol = true; } else if (!HttpParser.isHttpProtocol(buf[pos])) { // 关键点在这一句，如果校验不通过，则会报参数异常 throw new IllegalArgumentException(sm.getString("iib.invalidHttpProtocol")); } pos++; } if ((end - start) > 0) { request.protocol().setBytes(buf, start, end - start); } else { request.protocol().setString(""); } return true; }