Filter过滤器复习笔记

xiaoxiao2021-02-27  611

编码格式 web.xml配置

<!-- 中文编码 --> <filter> <filter-name>chinesefiter</filter-name> <filter-class>com.eduask.control.filter.ChineseFilter</filter-class> </filter> <filter-mapping> <filter-name>chinesefiter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>

实现Filter

public class ChineseFilter implements Filter{ public void destroy() { } @Override public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException { req.setCharacterEncoding("utf-8"); resp.setContentType("text/html;charset=utf-8"); resp.setCharacterEncoding("utf-8"); chain.doFilter(req, resp); } public void init(FilterConfig arg0) throws ServletException { } }

过滤敏感词 1、敏感词设置

public class WordUtil { // 过滤单词的工具,有增删改要过滤的内容的功能 单例 private static List list = new ArrayList(); // 初始化的单词 static { list.add("fuck"); } public static List getWords() { return list; } //增加敏感词 public static void addWords(String name) { list.add(name); } //移除敏感词 public static void remove(String name) { for (int i = 0; i < list.size(); i++) { if (list.get(i) == "b") { list.remove(i--); } } } //修改敏感词 }

2、设置到servlet,重写里面的方法

public class MyFilterForWord extends HttpServletRequestWrapper{ //包装类 public MyFilterForWord(HttpServletRequest request) { super(request); } //重新getParameter方法 public String getParameter(String name){ String words=super.getParameter(name); //之前的e System.out.println("过滤前的内容:"+words); List<String> list=WordUtil.getWords(); for(String l:list){ words=words.replace(l, "**"); } System.out.println(); return words; } }

3、web.xml设置

<!-- 过滤敏感词 --> <filter> <filter-name>sensitive</filter-name> <filter-class>com.eduask.control.filter.SensitiveWordsFilter</filter-class> </filter> <filter-mapping> <filter-name>sensitive</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>

实现Filter

public class SensitiveWordsFilter implements Filter{ public void destroy() { } @Override public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException { //将req转为http HttpServletRequest hreq=(HttpServletRequest) req; MyFilterForWord myfilter=new MyFilterForWord(hreq); // 设置过滤后的req chain.doFilter(myfilter, resp); } public void init(FilterConfig arg0) throws ServletException { } }

中文编码过滤

<!-- 编码过滤器 --> <filter> <filter-name>setCharacterEncoding</filter-name> <filter-class>com.edusak.filter.EncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>utf-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>setCharacterEncoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> // public class EncodingFilter implements Filter { private String encoding; private Map<String,String> params=new HashMap<String,String>(); @Override public void init(FilterConfig config) throws ServletException { //初始化 encoding=config.getInitParameter("encoding"); for(Enumeration e=config.getInitParameterNames();e.hasMoreElements();){ String name=(String) e.nextElement(); String value=config.getInitParameter(name); params.put(name, value); } } @Override public void destroy() { System.out.println("end do the coding filter"); params=null; encoding=null; } @Override public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException { req.setCharacterEncoding(encoding); chain.doFilter(req, resp); } }
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