<filter>

        <filter-name>CharacterEncodingFilter</filter-name>

        <filter-class>de.bvb.web.filter.CharacterEncodingFilter</filter-class>

        <init-param>

            <param-name>characterEncoding</param-name>

            <param-value>UTF-8</param-value>

        </init-param>

    </filter>

    <filter-mapping>

        <filter-name>CharacterEncodingFilter</filter-name>

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

        <dispatcher>REQUEST</dispatcher>

        <dispatcher>FORWARD</dispatcher>

    </filter-mapping> 

package de.bvb.web.filter;

import java.io.IOException;

import java.io.UnsupportedEncodingException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletRequestWrapper;

import javax.servlet.http.HttpServletResponse;

/**

 *

 * <p><b>Function:     处理全站乱码问题

 * </b></p>Class Name: CharacterEncodingFilter<br/>

 * Date:2016-12-13下午3:31:40<br/>author:Administrator<br/>since: JDK 1.6<br/>

 */

public class CharacterEncodingFilter implements Filter {

    private String charset = "UTF-8"; //默认编码设置为 UTF-8

    @Override

    public void init(FilterConfig filterConfig) throws ServletException {

        String charset = filterConfig.getInitParameter("characterEncoding");

        if (charset != null && !charset.equals("")) {

            this.charset = charset;

        }

    }

    @Override

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) req;

        HttpServletResponse response = (HttpServletResponse) resp;

        request.setCharacterEncoding(charset); //只能处理post方式的请求乱码

        response.setCharacterEncoding(charset);

        response.setContentType("text/html;charset=" + charset);

        chain.doFilter(new CharacterEncodingHttpServletRequest(request), response);

    }

    /**

     *

     * <p><b>Function:     使用包装设计模式处理get方式的请求乱码

     * </b></p>Class Name: CharacterEncodingHttpServletRequest<br/>

     * Date:2016-12-13下午3:45:29<br/>author:Administrator<br/>since: JDK 1.6<br/>

     */

    class CharacterEncodingHttpServletRequest extends HttpServletRequestWrapper {

        private HttpServletRequest request;

        public CharacterEncodingHttpServletRequest(HttpServletRequest request) {

            super(request);

            this.request = request;

        }

        @Override

        public String getParameter(String name) {

            String value = request.getParameter(name);

            if (!"get".equalsIgnoreCase(request.getMethod())) { //如果是非get方法,直接返回

                return value;

            }

            if (value == null) {

                return null;

            }

            try {

                return value = new String(value.getBytes("iso8859-1"), request.getCharacterEncoding());

            } catch (UnsupportedEncodingException e) {

                throw new RuntimeException(e);

            }

        }

    }

    @Override

    public void destroy() {

    }

}

package de.bvb.web.filter;

import java.io.IOException;

import java.io.UnsupportedEncodingException;

import java.lang.reflect.InvocationHandler;

import java.lang.reflect.Method;

import java.lang.reflect.Proxy;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletRequestWrapper;

import javax.servlet.http.HttpServletResponse;

/**

 *

 * <p><b>Function:     通过动态代理技术处理全站乱码问题

 * </b></p>Class Name: CharacterEncodingFilter<br/>

 * Date:2016-12-13下午3:31:40<br/>author:Administrator<br/>since: JDK 1.6<br/>

 */

public class CharacterEncodingFilter implements Filter {

    private String charset = "UTF-8"; //默认编码设置为 UTF-8

    @Override

    public void init(FilterConfig filterConfig) throws ServletException {

        String charset = filterConfig.getInitParameter("characterEncoding");

        if (charset != null && !charset.equals("")) {

            this.charset = charset;

        }

    }

    @Override

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {

        final HttpServletRequest request = (HttpServletRequest) req;

        HttpServletResponse response = (HttpServletResponse) resp;

        request.setCharacterEncoding(charset); //只能处理post方式的请求乱码

        response.setCharacterEncoding(charset);

        response.setContentType("text/html;charset=" + charset);

        chain.doFilter((ServletRequest) Proxy.newProxyInstance(CharacterEncodingFilter.class.getClassLoader(), HttpServletRequest.class.getInterfaces(),

                new InvocationHandler() {

                    @Override

                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

                        //改写 getParameter() 方法在get请求时候的功能

                        if ("get".equalsIgnoreCase(request.getMethod()) && "getParameter".equals(method.getName())) {

                            String value = (String) method.invoke(request, args);

                            if (value == null) {

                                return null;

                            }

                            return new String(value.getBytes("iso8859-1"), request.getCharacterEncoding());

                        }

                        return method.invoke(request, args);

                    }

                }), response);

    }

    @Override

    public void destroy() {

    }

}