需求：
1. 對day17_case案例錄入的數據進行敏感詞匯過濾
2. 敏感詞匯參考《敏感詞匯.txt》
3. 如果是敏感詞匯，替換為 ***

分析：1.對request對象進行增強(動態代理)，增強獲取參數相關方法2.放行，傳遞代理對象

SensitiveWordsFilter：

package cn.itcast.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;/*** 敏感詞匯過濾器*/ @WebFilter("/*") public class SensitiveWordsFilter implements Filter {// 敏感詞匯集合private List<String> list = new ArrayList<String>();@Overridepublic void init(FilterConfig filterConfig) throws ServletException {BufferedReader br = null;try {// 1.加載文件真實路徑ServletContext servletContext = filterConfig.getServletContext();// 獲取src下的敏感詞匯// 該處realPath可以使用getResourcesAsStream獲取String realPath = servletContext.getRealPath("/WEB-INF/classes/敏感詞匯.txt");// 2.讀取文件br = new BufferedReader(new FileReader(realPath));// 3.將文件的每一行數據添加到list中String line = null;while ((line = br.readLine()) != null) {list.add(line);}} catch (Exception e) {e.printStackTrace();} finally {if (br != null) {try {br.close();} catch (IOException e) {e.printStackTrace();}}}System.out.println(list);}@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {// 1.創建代理對象，ServletRequest proxy_request = (ServletRequest) Proxy.newProxyInstance(servletRequest.getClass().getClassLoader(),servletRequest.getClass().getInterfaces(),new InvocationHandler() {@Overridepublic Object invoke(Object proxy, Method method, Object[] args) throws Throwable {// 增強getParameter方法// 判斷是否是getParameter方法if ("getParameter".equals(method.getName())) {// 使用真實對象request,獲取前端請求中返回的參數并增強該參數String value = (String) method.invoke(servletRequest, args);if (value != null) {// 遍歷文件配置文件中獲取的敏感詞匯for (String str : list) {if (value.contains(str)) {value = value.replaceAll(str, "***");}}}// 返回增強后的返回值為替換了敏感詞匯的返回值return value;}// 判斷方法是否是getParameterMap// 需要實現// 判斷方法是否是getParameterValue// 需要實現// getParameter方法以外的方法正常執行return method.invoke(servletRequest, args);}});// 2.放行filterChain.doFilter(proxy_request, servletResponse);}@Overridepublic void destroy() {} }

TestServlet：

package cn.itcast.web.servlet;import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException;@WebServlet("/testServlet") public class TestServlet extends HttpServlet {protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// 從前臺輸入tomcat中設定好的url以及name參數和msg參數// msg的值或name的值可以使用配置文件中的敏感詞匯String name = request.getParameter("name");String msg = request.getParameter("msg");// 敏感詞匯將替換成 張三：你個***你個大***System.out.println(name+"："+msg);}protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doPost(request, response);} }

敏感詞匯.txt 該文件在src下

笨蛋 壞蛋 其他敏感詞匯可以自行添加

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