过滤器解决中文乱码

package com.buy.util;

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 {

	protected String encoding = null;

	protected FilterConfig filterConfig = null;

	protected boolean ignore = true;

	public void destroy() {
		this.encoding = null;
		this.filterConfig = null;
	}


	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		if (ignore || (request.getCharacterEncoding() == null)) {
			request.setCharacterEncoding(selectEncoding(request));
		}
		chain.doFilter(request, response);
	}

	public void init(FilterConfig filterConfig) throws ServletException {

		this.filterConfig = filterConfig;
		this.encoding = filterConfig.getInitParameter("encoding");
		String value = filterConfig.getInitParameter("ignore");
		if (value == null)
			this.ignore = true;
		else if (value.equalsIgnoreCase("true")
				|| value.equalsIgnoreCase("yes"))
			this.ignore = true;
		else
			this.ignore = false;
	}

	protected String selectEncoding(ServletRequest request) {
		return (this.encoding);
	}

	public FilterConfig getFilterConfig() {
		return filterConfig;
	}

	public void setFilterConfig(FilterConfig filterConfig) {
		this.filterConfig = filterConfig;
	}

}

 在web.xml中配置：

<filter>
		<filter-name>SetCharsetEncodingFilter</filter-name>
		<filter-class>com.buy.util.EncodingFilter</filter-class>
		<init-param>
			<param-name>encoding</param-name>
			<param-value>utf-8</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>SetCharsetEncodingFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>