使用动态代理对象进行敏感字过滤

package com.hopetesting.web.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.List;

/**
 * @author newcityman
 * @date 2019/9/13 - 19:41
 */
@WebFilter("/*")
public class SensitiveWordsFilter implements Filter {
    public void destroy() {
    }

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {
        //1、创建代理对象，增强getParameter方法
        ServletRequest proxy_req = (ServletRequest) Proxy.newProxyInstance(req.getClass().getClassLoader(), req.getClass().getInterfaces(), new InvocationHandler() {
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                //判断是否是getParameter方法
                //如果是，增强getParameter方法
                if (method.getName().equals("getParameter")) {
                    //增强返回值
                    //获取返回值
                    String value = (String) method.invoke(req, args);
                    if (value != null) {
                        for (String str : list) {
                            if (value.contains(str)) {
                                value = value.replace(str, "******");
                            }
                        }
                    }
                    return value;
                }
                return method.invoke(req, args);
            }
        });
        chain.doFilter(proxy_req, resp);
    }

    private List<String> list = new ArrayList<String>(); //敏感词汇集合

    public void init(FilterConfig config) throws ServletException {
        try {
            //1、获取文件的真实路径
            ServletContext servletContext = config.getServletContext();
            String realPath = servletContext.getRealPath("/WEB-INF/classes/敏感词汇.txt");
            //2、读取文件
            BufferedReader br = new BufferedReader(new FileReader(realPath));
            //3、将文件的每一行读取到list中
            String line = null;
            while ((line = br.readLine()) != null) {
                list.add(line);
            }
            br.close();
            System.out.println(list);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}