屏蔽非法字符就这么简单

package com.zhangkai.Filter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;public class FilterToWord implements Filter {//销毁，当服务器关闭的时候，也就destroy了。@Overridepublic void destroy() {}//过滤@Overridepublic void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {//首先拿到你输入的字符String content = request.getParameter("content");//第二步，判断一下拿到的值是不是空值if (content != null) {//比如我们规定含有AAA的是非法字符if (content.indexOf("AAA") == -1) {//如果不包含，则继续往下操作chain.doFilter(request, response);} else {//反之，就提示用户，输入有误System.out.println("有非法文字");//如果有需要依然可以使用request.getRequestDispatcher跳转}} else {//如果是空值，则继续操作chain.doFilter(request, response);}}//初始化，服务器一打开就init。@Overridepublic void init(FilterConfig arg0) throws ServletException {}}