package k.filter;

import javax.servlet.*;

import javax.servlet.http.HttpServlet;

import java.io.IOException;

public class EncodingFilter extends HttpServlet implements javax.servlet.Filter {

    @Override

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse,

                         FilterChain filterChain) throws IOException, ServletException {

        servletRequest.setCharacterEncoding("utf-8");

        servletResponse.setCharacterEncoding("utf-8");

        filterChain.doFilter(servletRequest,servletResponse);

    }

    @Override

    public void init(FilterConfig filterConfig) throws ServletException {

    }

}

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"

         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"

         version="3.1">

    <servlet>

        <servlet-name>action</servlet-name>

        <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>

        <init-param>

            <param-name>config</param-name>

            <param-value>/WEB-INF/config/struts-config.xml</param-value>

        </init-param>

        <load-on-startup>2</load-on-startup>

    </servlet>

    <servlet-mapping>

        <servlet-name>action</servlet-name>

        <url-pattern>*.do</url-pattern>

    </servlet-mapping>

    <filter>

        <filter-name>EncodingFilter</filter-name>

        <filter-class>k.filter.EncodingFilter</filter-class>

    </filter>

    <filter-mapping>

        <filter-name>EncodingFilter</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>

    <welcome-file-list>

        <welcome-file>index.jsp</welcome-file>

    </welcome-file-list>

</web-app>