<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>过滤器应用示例---敏感词过滤</title>
</head>
<body>
<form action="noteServlet" method="post" accept-charset="UTF-8" >
姓名:<input type="text" name="name"> <br>
留言:<input type="text" name="note" ><br>
<input type="submit" value="提交">
</form>
</body>
</html>
package com.item.filter;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.List;
/**
* 1.分析：
* 1.1 对request对象进行增强。增强获取参数相关方法
* 1.2 放行。传递代理对象
* 2.实现敏感词汇的过滤
*/
@WebFilter("/*")
public class SenstiveWordsFilter implements Filter
{
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException
{
/**
* 1.创建代理对象，增强getParameter方法
* 2.放行
*/
ServletRequest proxyServletRequest = (ServletRequest) Proxy.newProxyInstance(servletRequest.getClass().getClassLoader(), servletRequest.getClass().getInterfaces(), new InvocationHandler()
{
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
{
/**
* 1.增强getParameter方法
* 2.首先要判断是不是getParameter方法
*/
if (method.getName().equals("getParameter"))
{
/**
* 1.增强返回值
* 2.获取返回值进行铭感词汇的过滤
*/
String value = (String) method.invoke(servletRequest, args);
if (value != null)
{
for (String str : list)
{
if (value.contains(str))
{
value = value.replaceAll(str, "**");
}
}
}
return value;
}
/**
* 1.如果不是就执行正是对象的方法
*/
return method.invoke(servletRequest, args);
}
});
filterChain.doFilter(proxyServletRequest, servletResponse);
}
private List<String> list = new ArrayList<String>();//存放敏感词汇的集合
@Override
public void init(FilterConfig filterConfig) throws ServletException
{
/**
* 1.将数据词汇添加到list中
* 2.对于Filter中的init()初始化方法仅执行一次，即初始化一次
*/
list.add("蠢货");
list.add("傻逼");
list.add("蠢蛋");
}
}
package com.item.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("/noteServlet")
public class NoteServlet extends HttpServlet
{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
{
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
{
/**
* 1.解决乱码
*/
req.setCharacterEncoding("utf-8");
resp.setContentType("text/html;charset=utf-8");
String name=req.getParameter("name");
String note = req.getParameter("note");
resp.getWriter().write(name+"的留言是："+note);
System.out.println(name+":"+note);
}
}
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