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。

过滤方式:主要通过对html标签进行转义的方式达到过滤的目的

话不多说,直接上代码

实现方式,共分为三步:

第一步:在springboot启动类上添加@ServletComponentScan注解,该注解会自动扫描到我们自定义的filter(还有其他方式,这里就不赘述了,大家有兴趣的可以自行百度)

第二步:定义request的包装类,重写其中的关键方法

import com.alibaba.fastjson.JSON;

import org.apache.commons.text.StringEscapeUtils;

import javax.servlet.ReadListener;

import javax.servlet.ServletInputStream;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletRequestWrapper;

import java.io.*;

import java.nio.charset.Charset;

import java.util.HashMap;

import java.util.Map;

/**

 * ServletRequest包装类,对request做XSS过滤处理

 * @author Jozz

 */

public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {

    public XssHttpServletRequestWrapper(HttpServletRequest request) {

        super(request);

    }

    @Override

    public String getHeader(String name) {

        return StringEscapeUtils.escapeHtml4(super.getHeader(name));

    }

    @Override

    public String getQueryString() {

        return StringEscapeUtils.escapeHtml4(super.getQueryString());

    }

    @Override

    public String getParameter(String name) {

        return StringEscapeUtils.escapeHtml4(super.getParameter(name));

    }

    @Override

    public String[] getParameterValues(String name) {

        String[] values = super.getParameterValues(name);

        if(values != null) {

            int length = values.length;

            String[] escapseValues = new String[length];

            for(int i = 0; i < length; i++){

                escapseValues[i] = StringEscapeUtils.escapeHtml4(values[i]);

            }

            return escapseValues;

        }

        return values;

    }

    @Override

    public ServletInputStream getInputStream() throws IOException {

        String str=getRequestBody(super.getInputStream());

        Map<String,Object> map= JSON.parseObject(str,Map.class);

        Map<String,Object> resultMap=new HashMap<>(map.size());

        for(String key:map.keySet()){

            Object val=map.get(key);

            if(map.get(key) instanceof String){

                resultMap.put(key,StringEscapeUtils.escapeHtml4(val.toString()));

            }else{

                resultMap.put(key,val);

            }

        }

        str=JSON.toJSONString(resultMap);

        final ByteArrayInputStream bais = new ByteArrayInputStream(str.getBytes());

        return new ServletInputStream() {

            @Override

            public int read() throws IOException {

                return bais.read();

            }

            @Override

            public boolean isFinished() {

                return false;

            }

            @Override

            public boolean isReady() {

                return false;

            }

            @Override

            public void setReadListener(ReadListener listener) {

            }

        };

    }

    private String getRequestBody(InputStream stream) {

        String line = "";

        StringBuilder body = new StringBuilder();

        int counter = 0;

        // 读取POST提交的数据内容

        BufferedReader reader = new BufferedReader(new InputStreamReader(stream, Charset.forName("UTF-8")));

        try {

            while ((line = reader.readLine()) != null) {

                body.append(line);

                counter++;

            }

        } catch (IOException e) {

            e.printStackTrace();

        }

        return body.toString();

    }

}

其中的StringEscapeUtils来自:

    compile("org.apache.commons:commons-text:1.6")

第三步:自定义过滤器

import javax.servlet.*;

import javax.servlet.annotation.WebFilter;

import javax.servlet.http.HttpServletRequest;

import java.io.IOException;

/**

 * XSS过滤器

 * @author Jozz

 */

@WebFilter(filterName="xssFilter",urlPatterns="/*")

public class XssFilter implements Filter {

    @Override

    public void init(javax.servlet.FilterConfig filterConfig) throws ServletException {

    }

    @Override

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest)servletRequest;

        String path = request.getServletPath();

        //由于我的@WebFilter注解配置的是urlPatterns="/*"(过滤所有请求),所以这里对不需要过滤的静态资源url,作忽略处理(大家可以依照具体需求配置)

        String[] exclusionsUrls = {".js",".gif",".jpg",".png",".css",".ico"};

        for (String str : exclusionsUrls) {

            if (path.contains(str)) {

                filterChain.doFilter(servletRequest,servletResponse);

                return;

            }

        }

        filterChain.doFilter(new XssHttpServletRequestWrapper(request),servletResponse);

    }

    @Override

    public void destroy() {

    }

}

到这里就大功告成了~若您觉得文章有用，欢迎点赞分享！