过滤器
有一些信息不应该被处理，要被过滤的。
1.导包
javax.servlet.jsp.jstl
jstl-api
1.2
taglibs
standard
1.1.2
javax.servlet.jsp
javax.servlet.jsp-api
2.3.2-b01
2.继承过滤器的接口
package com.javaweb.controller;
import javax.servlet.*;
import java.io.IOException;
/**
* @author panglili
* @create 2022-07-20-20:32
*/
public class FilterDemo1 implements Filter {
public void init(FilterConfig filterConfig) throws ServletException {
}
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
servletRequest.setCharacterEncoding("utf-8");
servletResponse.setCharacterEncoding("utf-8");
servletResponse.setContentType("text/html;charset=utf-8");
System.out.println("****before:");
//让请求继续执行，如果不写请求到这里就会停止
filterChain.doFilter(servletRequest,servletResponse);
System.out.println("####after:");
}
public void destroy() {
System.out.println("destory......");
}
}
3.写一个没有处理编码的请求
package com.javaweb.servlet;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* @author panglili
* @create 2022-07-20-8:26
*/
public class tets extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
ServletContext context = this.getServletContext();
String username="弄啥嘞~";
context.setAttribute("username",username);
resp.getWriter().write(username);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}
此时还没有配置过滤器，看看网页效果
![[javaweb]过滤器处理乱码](https://johngo-pic.oss-cn-beijing.aliyuncs.com/articles/20230605/2884728-20220723182815114-866318871.png)
![[javaweb]过滤器处理乱码](https://www.johngo689.com/wp-content/themes/justnews/themer/assets/images/lazy.png)
意料之中的乱码。
4.将过滤器注册到web配置
encoding
com.javaweb.controller.FilterDemo1
encoding
/filter
5.经过过滤器的处理
![[javaweb]过滤器处理乱码](https://johngo-pic.oss-cn-beijing.aliyuncs.com/articles/20230605/2884728-20220723182836412-355454336.png)
Original: https://www.cnblogs.com/lumanmanqixiuyuanxi/p/16512704.html
Author: 路漫漫qixiuyuanxi
Title: [javaweb]过滤器处理乱码
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