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 EcodeFilter implements Filter {

	// 定义编码方式 默认为空

	private String encoding =null;

	public void destroy() {

	}

	// 自动调用过滤方法 doFilter

	public void doFilter(ServletRequest request, ServletResponse response,

			FilterChain chain) throws IOException, ServletException {

		// 如果编码不为空就过滤请求中的数据

		if (encoding != null) {

			// 设置request字符编码

			request.setCharacterEncoding(encoding);

			// 设置response字符编码

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

		}

		// 传递给下一个过滤器或者下一个servlet/jsp

		chain.doFilter(request, response);

	}

	public void init(FilterConfig config) throws ServletException {

		//将web.xml中的过滤器的配置编码取出来赋值给  encoding

		encoding=config.getInitParameter("encoding");

	}

}

<!-- 编码过滤器，针对所有的地址都过滤 -->

	<filter>

		<filter-name>encodefilter</filter-name>

		<filter-class>com.bw.shop.util.EcodeFilter</filter-class>

		<init-param>

			<param-name>encoding</param-name>

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

		</init-param>

	</filter>

	<filter-mapping>

		<filter-name>encodefilter</filter-name>

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

	</filter-mapping>