Springboot配置XSS过滤器XssFilter

不念不忘少年蓝@ 2023-10-04 17:16 12阅读 0赞

简单介绍：

XSS : 跨站脚本攻击(Cross Site Scripting)，为不和层叠样式表(Cascading Style Sheets, CSS)的缩写混淆，故将跨站脚本攻击缩写为XSS。恶意攻击者往Web页面里插入恶意html代码，当用户浏览该页之时，嵌入其中Web里面的html代码会被执行，从而达到恶意攻击用户的特殊目的。

源码地址：[Springboot配置XSS过滤器XssFilter.zip-网络安全文档类资源-CSDN下载][Springboot_XSS_XssFilter.zip-_-CSDN]

项目结构

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5rab5ZOl5piv5Liq5aSn5biF5q-U_size_8_color_FFFFFF_t_70_g_se_x_16][]

关键代码：

**1.XssFilter.java**

package com.xss;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
 import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServletRequest;
 
 import org.apache.commons.lang3.StringUtils;
 
 
 /**
 * xss过滤
 */
 public class XssFilter implements Filter {
 
 //不拦截的地址
 	private List<String> excludedList = new ArrayList<String>();
 	
 	@Override
 	public void init(FilterConfig config) throws ServletException {
 
 /*
 		 * 这里只处理了不拦截的url地址，如果想不拦截某个字段，比如富文本字段，
 		 * 需要自己在XssHttpServletRequestWrapper类中去添加逻辑
 		 */
 		excludedList.add("/test/excluded1");
 		excludedList.add("/test/excluded2");
 	}
 
 	@Override
 	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
 throws IOException, ServletException {
 		XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper(
 				(HttpServletRequest) request);
 		String url = xssRequest.getServletPath();
 		if(isExcluded(url)){
 			chain.doFilter(request, response);
 		}else{
 			//使用XSS过滤
 			chain.doFilter(xssRequest, response);
 		}
 	}
 
 	@Override
 	public void destroy() {
 	}
 
 	/**
 	 * 是否不拦截
 	 * @param url	请求地址
 	 * @return	true不拦截，false拦截
 	 */
 	private boolean isExcluded(String url){
 		if(StringUtils.isBlank(url)){
 			return false;
 		}
 		
 		for (String excluded : excludedList) {
 			if(url.contains(excluded)){
 				return true;
 			}
 		}
 		return false;
 	}
 
 }

**2.XssHttpServletRequestWrapper.java**

package com.xss;
 
 import org.apache.commons.lang3.StringEscapeUtils;
 import org.apache.commons.lang3.StringUtils;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletRequestWrapper;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import javax.servlet.ReadListener;
 import javax.servlet.ServletInputStream;
 import org.apache.commons.io.IOUtils;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
 
 public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
 
 // 没被包装过的HttpServletRequest（特殊场景，需求自己过滤）
 HttpServletRequest orgRequest;
 // html过滤
 private final static HTMLFilter htmlFilter = new HTMLFilter();
 
 public XssHttpServletRequestWrapper(HttpServletRequest request) {
 super(request);
 orgRequest = request;
 }
 
 
 /**
 * 过滤json参数
 */
 @Override
 public ServletInputStream getInputStream() throws IOException {
 String contentType = super.getHeader(HttpHeaders.CONTENT_TYPE);
 //非json类型，直接返回
 if(!(MediaType.APPLICATION_JSON_VALUE.
 equalsIgnoreCase(contentType) || 
 MediaType.APPLICATION_JSON_UTF8_VALUE.
 equalsIgnoreCase(contentType))){
 return super.getInputStream();
 }
 
 //为空，直接返回
 String json = IOUtils.toString(super.getInputStream(), "utf-8");
 if (StringUtils.isBlank(json)) {
 return super.getInputStream();
 }
 
 //xss过滤
 json =xssEncode(json);
 json = StringEscapeUtils.unescapeHtml4(json);
 
 final ByteArrayInputStream bis = 
 new ByteArrayInputStream(json.getBytes("utf-8"));
 
 return new ServletInputStream() {
 @Override
 public boolean isFinished() {
 return true;
 }
 
 @Override
 public boolean isReady() {
 return true;
 }
 
 @Override
 public void setReadListener(ReadListener readListener) {
 }
 
 @Override
 public int read() throws IOException {
 return bis.read();
 }
 };
 }
 
 
 @Override
 public String getParameter(String name) {
 String value = super.getParameter(xssEncode(name));
 if (StringUtils.isNotBlank(value)) {
 value =xssEncode(value);
 }
 
 return StringEscapeUtils.unescapeHtml4(value);
 }
 
 @Override
 public String[] getParameterValues(String name) {
 String[] parameters = super.getParameterValues(name);
 if (parameters == null || parameters.length == 0) {
 return null;
 }
 
 for (int i = 0; i < parameters.length; i++) {
 parameters[i] = xssEncode(parameters[i]);
 parameters[i] = StringEscapeUtils.unescapeHtml4(parameters[i]);
 }
 return parameters;
 }
 
 @Override
 public Map<String, String[]> getParameterMap() {
 Map<String, String[]> map = new LinkedHashMap<>();
 Map<String, String[]> parameters = super.getParameterMap();
 for (String key : parameters.keySet()) {
 String[] values = parameters.get(key);
 for (int i = 0; i < values.length; i++) {
 values[i] = xssEncode(values[i]);
 values[i] = StringEscapeUtils.unescapeHtml4(values[i]);
 }
 map.put(key, values);
 }
 return map;
 }
 
 @Override
 public String getHeader(String name) {
 String value = super.getHeader(xssEncode(name));
 if (StringUtils.isNotBlank(value)) {
 value = xssEncode(value);
 }
 
 return StringEscapeUtils.unescapeHtml4(value);
 }
 
 private String xssEncode(String input) {
 return htmlFilter.filter(input);
 }
 
 /**
 * 获取最原始的request
 */
 public HttpServletRequest getOrgRequest() {
 return orgRequest;
 }
 
 /**
 * 获取最原始的request
 */
 public static HttpServletRequest getOrgRequest(HttpServletRequest request) {
 if (request instanceof XssHttpServletRequestWrapper) {
 return ((XssHttpServletRequestWrapper) request).getOrgRequest();
 }
 
 return request;
 }
 
 }

**3.HTMLFilter.java**

package com.xss;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.logging.Logger;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 /**
 *
 * HTML filtering utility for protecting against XSS (Cross Site Scripting).
 *
 * This code is licensed LGPLv3
 *
 * This code is a Java port of the original work in PHP by Cal Hendersen.
 * http://code.iamcal.com/php/lib_filter/
 *
 * The trickiest part of the translation was handling the differences in regex handling
 * between PHP and Java. These resources were helpful in the process:
 *
 * http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/Pattern.html
 * http://us2.php.net/manual/en/reference.pcre.pattern.modifiers.php
 * http://www.regular-expressions.info/modifiers.html
 *
 * A note on naming conventions: instance variables are prefixed with a "v"; global
 * constants are in all caps.
 *
 * Sample use:
 * String input = ...
 * String clean = new HTMLFilter().filter( input );
 *
 * The class is not thread safe. Create a new instance if in doubt.
 *
 * If you find bugs or have suggestions on improvement (especially regarding
 * performance), please contact us. The latest version of this
 * source, and our contact details, can be found at http://xss-html-filter.sf.net
 *
 * @author Joseph O'Connell
 * @author Cal Hendersen
 * @author Michael Semb Wever
 */
 public class HTMLFilter {
 
 /** regex flag union representing /si modifiers in php **/
 private static final int REGEX_FLAGS_SI = Pattern.CASE_INSENSITIVE | Pattern.DOTALL;
 private static final Pattern P_COMMENTS = Pattern.compile("", Pattern.DOTALL);
 private static final Pattern P_COMMENT = Pattern.compile("^!--(.*)--$", REGEX_FLAGS_SI);
 private static final Pattern P_TAGS = Pattern.compile("<(.*?)>", Pattern.DOTALL);
 private static final Pattern P_END_TAG = Pattern.compile("^/([a-z0-9]+)", REGEX_FLAGS_SI);
 private static final Pattern P_START_TAG = Pattern.compile("^([a-z0-9]+)(.*?)(/?)$", REGEX_FLAGS_SI);
 private static final Pattern P_QUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)=([\"'])(.*?)\\2", REGEX_FLAGS_SI);
 private static final Pattern P_UNQUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)(=)([^\"\\s']+)", REGEX_FLAGS_SI);
 private static final Pattern P_PROTOCOL = Pattern.compile("^([^:]+):", REGEX_FLAGS_SI);
 private static final Pattern P_ENTITY = Pattern.compile("&#(\\d+);?");
 private static final Pattern P_ENTITY_UNICODE = Pattern.compile("&#x([0-9a-f]+);?");
 private static final Pattern P_ENCODE = Pattern.compile("%([0-9a-f]{2});?");
 private static final Pattern P_VALID_ENTITIES = Pattern.compile("&([^&;]*)(?=(;|&|$))");
 private static final Pattern P_VALID_QUOTES = Pattern.compile("(>|^)([^<]+?)(<|$)", Pattern.DOTALL);
 private static final Pattern P_END_ARROW = Pattern.compile("^>");
 private static final Pattern P_BODY_TO_END = Pattern.compile("<([^>]*?)(?=<|$)");
 private static final Pattern P_XML_CONTENT = Pattern.compile("(^|>)([^<]*?)(?=>)");
 private static final Pattern P_STRAY_LEFT_ARROW = Pattern.compile("<([^>]*?)(?=<|$)");
 private static final Pattern P_STRAY_RIGHT_ARROW = Pattern.compile("(^|>)([^<]*?)(?=>)");
 private static final Pattern P_AMP = Pattern.compile("&");
 private static final Pattern P_QUOTE = Pattern.compile("\"");
 private static final Pattern P_LEFT_ARROW = Pattern.compile("<");
 private static final Pattern P_RIGHT_ARROW = Pattern.compile(">");
 private static final Pattern P_BOTH_ARROWS = Pattern.compile("<>");
 private static final Pattern P_DOUBLE_QUOT = Pattern.compile(""");
 
 // @xxx could grow large... maybe use sesat's ReferenceMap
 private static final ConcurrentMap<String,Pattern> P_REMOVE_PAIR_BLANKS = new ConcurrentHashMap<String, Pattern>();
 private static final ConcurrentMap<String,Pattern> P_REMOVE_SELF_BLANKS = new ConcurrentHashMap<String, Pattern>();
 
 /** set of allowed html elements, along with allowed attributes for each element **/
 private final Map<String, List<String>> vAllowed;
 /** counts of open tags for each (allowable) html element **/
 private final Map<String, Integer> vTagCounts = new HashMap<String, Integer>();
 
 /** html elements which must always be self-closing (e.g. "<img />") **/
 private final String[] vSelfClosingTags;
 /** html elements which must always have separate opening and closing tags (e.g. "") **/
 private final String[] vNeedClosingTags;
 /** set of disallowed html elements **/
 private final String[] vDisallowed;
 /** attributes which should be checked for valid protocols **/
 private final String[] vProtocolAtts;
 /** allowed protocols **/
 private final String[] vAllowedProtocols;
 /** tags which should be removed if they contain no content (e.g. "" or "") **/
 private final String[] vRemoveBlanks;
 /** entities allowed within html markup **/
 private final String[] vAllowedEntities;
 /** flag determining whether comments are allowed in input String. */
 private final boolean stripComment;
 private final boolean encodeQuotes;
 private boolean vDebug = false;
 /**
 * flag determining whether to try to make tags when presented with "unbalanced"
 * angle brackets (e.g. "" becomes " text "). If set to false,
 * unbalanced angle brackets will be html escaped.
 */
 private final boolean alwaysMakeTags;
 
 /** Default constructor.
 *
 */
 public HTMLFilter() {
 vAllowed = new HashMap<>();
 
 final ArrayList<String> a_atts = new ArrayList<String>();
 a_atts.add("href");
 a_atts.add("target");
 vAllowed.put("a", a_atts);
 
 final ArrayList<String> img_atts = new ArrayList<String>();
 img_atts.add("src");
 img_atts.add("width");
 img_atts.add("height");
 img_atts.add("alt");
 vAllowed.put("img", img_atts);
 
 final ArrayList<String> no_atts = new ArrayList<String>();
 vAllowed.put("b", no_atts);
 vAllowed.put("strong", no_atts);
 vAllowed.put("i", no_atts);
 vAllowed.put("em", no_atts);
 
 vSelfClosingTags = new String[]{"img"};
 vNeedClosingTags = new String[]{"a", "b", "strong", "i", "em"};
 vDisallowed = new String[]{};
 vAllowedProtocols = new String[]{"http", "mailto", "https"}; // no ftp.
 vProtocolAtts = new String[]{"src", "href"};
 vRemoveBlanks = new String[]{"a", "b", "strong", "i", "em"};
 vAllowedEntities = new String[]{"amp", "gt", "lt", "quot"};
 stripComment = true;
 encodeQuotes = true;
 alwaysMakeTags = true;
 }
 
 /** Set debug flag to true. Otherwise use default settings. See the default constructor.
 *
 * @param debug turn debug on with a true argument
 */
 public HTMLFilter(final boolean debug) {
 this();
 vDebug = debug;
 
 }
 
 /** Map-parameter configurable constructor.
 *
 * @param conf map containing configuration. keys match field names.
 */
 public HTMLFilter(final Map<String,Object> conf) {
 
 assert conf.containsKey("vAllowed") : "configuration requires vAllowed";
 assert conf.containsKey("vSelfClosingTags") : "configuration requires vSelfClosingTags";
 assert conf.containsKey("vNeedClosingTags") : "configuration requires vNeedClosingTags";
 assert conf.containsKey("vDisallowed") : "configuration requires vDisallowed";
 assert conf.containsKey("vAllowedProtocols") : "configuration requires vAllowedProtocols";
 assert conf.containsKey("vProtocolAtts") : "configuration requires vProtocolAtts";
 assert conf.containsKey("vRemoveBlanks") : "configuration requires vRemoveBlanks";
 assert conf.containsKey("vAllowedEntities") : "configuration requires vAllowedEntities";
 
 vAllowed = Collections.unmodifiableMap((HashMap<String, List<String>>) conf.get("vAllowed"));
 vSelfClosingTags = (String[]) conf.get("vSelfClosingTags");
 vNeedClosingTags = (String[]) conf.get("vNeedClosingTags");
 vDisallowed = (String[]) conf.get("vDisallowed");
 vAllowedProtocols = (String[]) conf.get("vAllowedProtocols");
 vProtocolAtts = (String[]) conf.get("vProtocolAtts");
 vRemoveBlanks = (String[]) conf.get("vRemoveBlanks");
 vAllowedEntities = (String[]) conf.get("vAllowedEntities");
 stripComment = conf.containsKey("stripComment") ? (Boolean) conf.get("stripComment") : true;
 encodeQuotes = conf.containsKey("encodeQuotes") ? (Boolean) conf.get("encodeQuotes") : true;
 alwaysMakeTags = conf.containsKey("alwaysMakeTags") ? (Boolean) conf.get("alwaysMakeTags") : true;
 }
 
 private void reset() {
 vTagCounts.clear();
 }
 
 private void debug(final String msg) {
 if (vDebug) {
 Logger.getAnonymousLogger().info(msg);
 }
 }
 
 //---------------------------------------------------------------
 // my versions of some PHP library functions
 public static String chr(final int decimal) {
 return String.valueOf((char) decimal);
 }
 
 public static String htmlSpecialChars(final String s) {
 String result = s;
 result = regexReplace(P_AMP, "&", result);
 result = regexReplace(P_QUOTE, """, result);
 result = regexReplace(P_LEFT_ARROW, "<", result);
 result = regexReplace(P_RIGHT_ARROW, ">", result);
 return result;
 }
 
 //---------------------------------------------------------------
 /**
 * given a user submitted input String, filter out any invalid or restricted
 * html.
 *
 * @param input text (i.e. submitted by a user) than may contain html
 * @return "clean" version of input, with only valid, whitelisted html elements allowed
 */
 public String filter(final String input) {
 reset();
 String s = input;
 
 debug("************************************************");
 debug(" INPUT: " + input);
 
 s = escapeComments(s);
 debug(" escapeComments: " + s);
 
 s = balanceHTML(s);
 debug(" balanceHTML: " + s);
 
 s = checkTags(s);
 debug(" checkTags: " + s);
 
 s = processRemoveBlanks(s);
 debug("processRemoveBlanks: " + s);
 
 s = validateEntities(s);
 debug(" validateEntites: " + s);
 
 debug("************************************************\n\n");
 return s;
 }
 
 public boolean isAlwaysMakeTags(){
 return alwaysMakeTags;
 }
 
 public boolean isStripComments(){
 return stripComment;
 }
 
 private String escapeComments(final String s) {
 final Matcher m = P_COMMENTS.matcher(s);
 final StringBuffer buf = new StringBuffer();
 if (m.find()) {
 final String match = m.group(1); //(.*?)
 m.appendReplacement(buf, Matcher.quoteReplacement(""));
 }
 m.appendTail(buf);
 
 return buf.toString();
 }
 
 private String balanceHTML(String s) {
 if (alwaysMakeTags) {
 //
 // try and form html
 //
 s = regexReplace(P_END_ARROW, "", s);
 s = regexReplace(P_BODY_TO_END, "<$1>", s);
 s = regexReplace(P_XML_CONTENT, "$1<$2", s);
 
 } else {
 //
 // escape stray brackets
 //
 s = regexReplace(P_STRAY_LEFT_ARROW, "<$1", s);
 s = regexReplace(P_STRAY_RIGHT_ARROW, "$1$2><", s);
 
 //
 // the last regexp causes '<>' entities to appear
 // (we need to do a lookahead assertion so that the last bracket can
 // be used in the next pass of the regexp)
 //
 s = regexReplace(P_BOTH_ARROWS, "", s);
 }
 
 return s;
 }
 
 private String checkTags(String s) {
 Matcher m = P_TAGS.matcher(s);
 
 final StringBuffer buf = new StringBuffer();
 while (m.find()) {
 String replaceStr = m.group(1);
 replaceStr = processTag(replaceStr);
 m.appendReplacement(buf, Matcher.quoteReplacement(replaceStr));
 }
 m.appendTail(buf);
 
 s = buf.toString();
 
 // these get tallied in processTag
 // (remember to reset before subsequent calls to filter method)
 for (String key : vTagCounts.keySet()) {
 for (int ii = 0; ii < vTagCounts.get(key); ii++) {
 s += "</" + key + ">";
 }
 }
 
 return s;
 }
 
 private String processRemoveBlanks(final String s) {
 String result = s;
 for (String tag : vRemoveBlanks) {
 if(!P_REMOVE_PAIR_BLANKS.containsKey(tag)){
 P_REMOVE_PAIR_BLANKS.putIfAbsent(tag, Pattern.compile("<" + tag + "(\\s[^>]*)?></" + tag + ">"));
 }
 result = regexReplace(P_REMOVE_PAIR_BLANKS.get(tag), "", result);
 if(!P_REMOVE_SELF_BLANKS.containsKey(tag)){
 P_REMOVE_SELF_BLANKS.putIfAbsent(tag, Pattern.compile("<" + tag + "(\\s[^>]*)?/>"));
 }
 result = regexReplace(P_REMOVE_SELF_BLANKS.get(tag), "", result);
 }
 
 return result;
 }
 
 private static String regexReplace(final Pattern regex_pattern, final String replacement, final String s) {
 Matcher m = regex_pattern.matcher(s);
 return m.replaceAll(replacement);
 }
 
 private String processTag(final String s) {
 // ending tags
 Matcher m = P_END_TAG.matcher(s);
 if (m.find()) {
 final String name = m.group(1).toLowerCase();
 if (allowed(name)) {
 if (!inArray(name, vSelfClosingTags)) {
 if (vTagCounts.containsKey(name)) {
 vTagCounts.put(name, vTagCounts.get(name) - 1);
 return "</" + name + ">";
 }
 }
 }
 }
 
 // starting tags
 m = P_START_TAG.matcher(s);
 if (m.find()) {
 final String name = m.group(1).toLowerCase();
 final String body = m.group(2);
 String ending = m.group(3);
 
 //debug( "in a starting tag, name='" + name + "'; body='" + body + "'; ending='" + ending + "'" );
 if (allowed(name)) {
 String params = "";
 
 final Matcher m2 = P_QUOTED_ATTRIBUTES.matcher(body);
 final Matcher m3 = P_UNQUOTED_ATTRIBUTES.matcher(body);
 final List<String> paramNames = new ArrayList<String>();
 final List<String> paramValues = new ArrayList<String>();
 while (m2.find()) {
 paramNames.add(m2.group(1)); //([a-z0-9]+)
 paramValues.add(m2.group(3)); //(.*?)
 }
 while (m3.find()) {
 paramNames.add(m3.group(1)); //([a-z0-9]+)
 paramValues.add(m3.group(3)); //([^\"\\s']+)
 }
 
 String paramName, paramValue;
 for (int ii = 0; ii < paramNames.size(); ii++) {
 paramName = paramNames.get(ii).toLowerCase();
 paramValue = paramValues.get(ii);
 
 // debug( "paramName='" + paramName + "'" );
 // debug( "paramValue='" + paramValue + "'" );
 // debug( "allowed? " + vAllowed.get( name ).contains( paramName ) );
 
 if (allowedAttribute(name, paramName)) {
 if (inArray(paramName, vProtocolAtts)) {
 paramValue = processParamProtocol(paramValue);
 }
 params += " " + paramName + "=\"" + paramValue + "\"";
 }
 }
 
 if (inArray(name, vSelfClosingTags)) {
 ending = " /";
 }
 
 if (inArray(name, vNeedClosingTags)) {
 ending = "";
 }
 
 if (ending == null || ending.length() < 1) {
 if (vTagCounts.containsKey(name)) {
 vTagCounts.put(name, vTagCounts.get(name) + 1);
 } else {
 vTagCounts.put(name, 1);
 }
 } else {
 ending = " /";
 }
 return "<" + name + params + ending + ">";
 } else {
 return "";
 }
 }
 
 // comments
 m = P_COMMENT.matcher(s);
 if (!stripComment && m.find()) {
 return "<" + m.group() + ">";
 }
 
 return "";
 }
 
 private String processParamProtocol(String s) {
 s = decodeEntities(s);
 final Matcher m = P_PROTOCOL.matcher(s);
 if (m.find()) {
 final String protocol = m.group(1);
 if (!inArray(protocol, vAllowedProtocols)) {
 // bad protocol, turn into local anchor link instead
 s = "#" + s.substring(protocol.length() + 1, s.length());
 if (s.startsWith("#//")) {
 s = "#" + s.substring(3, s.length());
 }
 }
 }
 
 return s;
 }
 
 private String decodeEntities(String s) {
 StringBuffer buf = new StringBuffer();
 
 Matcher m = P_ENTITY.matcher(s);
 while (m.find()) {
 final String match = m.group(1);
 final int decimal = Integer.decode(match).intValue();
 m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal)));
 }
 m.appendTail(buf);
 s = buf.toString();
 
 buf = new StringBuffer();
 m = P_ENTITY_UNICODE.matcher(s);
 while (m.find()) {
 final String match = m.group(1);
 final int decimal = Integer.valueOf(match, 16).intValue();
 m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal)));
 }
 m.appendTail(buf);
 s = buf.toString();
 
 buf = new StringBuffer();
 m = P_ENCODE.matcher(s);
 while (m.find()) {
 final String match = m.group(1);
 final int decimal = Integer.valueOf(match, 16).intValue();
 m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal)));
 }
 m.appendTail(buf);
 s = buf.toString();
 
 s = validateEntities(s);
 return s;
 }
 
 private String validateEntities(final String s) {
 StringBuffer buf = new StringBuffer();
 
 // validate entities throughout the string
 Matcher m = P_VALID_ENTITIES.matcher(s);
 while (m.find()) {
 final String one = m.group(1); //([^&;]*)
 final String two = m.group(2); //(?=(;|&|$))
 m.appendReplacement(buf, Matcher.quoteReplacement(checkEntity(one, two)));
 }
 m.appendTail(buf);
 
 return encodeQuotes(buf.toString());
 }
 
 private String encodeQuotes(final String s){
 if(encodeQuotes){
 StringBuffer buf = new StringBuffer();
 Matcher m = P_VALID_QUOTES.matcher(s);
 while (m.find()) {
 final String one = m.group(1); //(>|^)
 final String two = m.group(2); //([^<]+?)
 final String three = m.group(3); //(<|$)
 m.appendReplacement(buf, Matcher.quoteReplacement(one + regexReplace(P_QUOTE, """, two) + three));
 }
 m.appendTail(buf);
 return buf.toString();
 }else{
 return s;
 }
 }
 
 private String checkEntity(final String preamble, final String term) {
 
 return ";".equals(term) && isValidEntity(preamble)
 ? '&' + preamble
 : "&" + preamble;
 }
 
 private boolean isValidEntity(final String entity) {
 return inArray(entity, vAllowedEntities);
 }
 
 private static boolean inArray(final String s, final String[] array) {
 for (String item : array) {
 if (item != null && item.equals(s)) {
 return true;
 }
 }
 return false;
 }
 
 private boolean allowed(final String name) {
 return (vAllowed.isEmpty() || vAllowed.containsKey(name)) && !inArray(name, vDisallowed);
 }
 
 private boolean allowedAttribute(final String name, final String paramName) {
 return allowed(name) && (vAllowed.isEmpty() || vAllowed.get(name).contains(paramName));
 }
 }

原文地址：[XSS过滤JAVA过滤器filter 防止常见SQL注入 - 现世安稳。 - 博客园][XSS_JAVA_filter _SQL_ - _ -]

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扩展：如果存在多个过滤器，比如：shiroFilter，使用FilterRegistrationBean

package com.config;
    
    import javax.servlet.DispatcherType;
    
    import org.springframework.boot.web.servlet.FilterRegistrationBean;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.filter.DelegatingFilterProxy;
    
    import com.xss.XssFilter;
    
    /**
     * Filter配置
     */
    @Configuration
    public class FilterConfig {
    
        @Bean
        public FilterRegistrationBean shiroFilterRegistration() {
            FilterRegistrationBean registration = new FilterRegistrationBean();
            registration.setFilter(new DelegatingFilterProxy("shiroFilter"));
            registration.addUrlPatterns("/*");//过滤所有路径
    		registration.setName("shiroFilter");//过滤器名称
    		registration.setOrder(Integer.MAX_VALUE - 1);//优先级，越低越优先
            return registration;
        }
    
        @Bean
        public FilterRegistrationBean xssFilterRegistration() {
            FilterRegistrationBean registration = new FilterRegistrationBean();
            registration.setFilter(new XssFilter());
            registration.addUrlPatterns("/*");//过滤所有路径
            registration.setName("xssFilter");//过滤器名称
            registration.setOrder(Integer.MAX_VALUE);//优先级，越低越优先
            return registration;
        }
    }

[Springboot_XSS_XssFilter.zip-_-CSDN]: https://download.csdn.net/download/u011974797/72548857
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[XSS_JAVA_filter _SQL_ - _ -]: https://www.cnblogs.com/hero123/p/9091625.html