[Source] EncodingFilter.java

package com.sample.utils;

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 EncodingFilter implements Filter {
    /**
     * 인코딩을 수행할 인코딩 캐릭터 셋 지정
     */
    private String         encoding     = null;

    /**
     * 필터 설정 관리자
     */
    protected FilterConfig filterConfig = null;

    /*
     * (non-Javadoc)
     * @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
     */
    public void init(FilterConfig filterConfig) throws ServletException {
        this.filterConfig = filterConfig;
        this.encoding = filterConfig.getInitParameter("encoding");
    }

    /*
     * (non-Javadoc)
     * @see javax.servlet.Filter#destroy()
     */
    public void destroy() {

        this.encoding = null;
        this.filterConfig = null;

    }

    /*
     * (non-Javadoc)
     * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
     */
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

        if (request.getCharacterEncoding() == null) {
            if (encoding != null) {
                request.setCharacterEncoding(encoding);
            }
        }

        chain.doFilter(request, response);
    }

    /**
     * @return
     */
    public FilterConfig getFilterConfig() {
        return filterConfig;
    }

    /**
     * @param cfg
     */
    public void setFilterConfig(FilterConfig cfg) {
        filterConfig = cfg;
    }
}