感谢：http://www.iteye.com/wiki/Struts/578-Struts原理与实践（5） 和Google
将所有的request的字符集也设置为UTF-8。虽然，我们可以在每个文件中加入这样的句子：request.setCharacterEncoding("UTF-8");来解决，但这样显得很麻烦。一种更简单的解决方法是使用filter。具体步骤如下： 在mystruts\WEB-INF\classes目录下再新建一个名为filters的目录，新建一个名为：SetCharacterEncodingFilter的类，并保存在该目录下。其实，这个类并不要您亲自来写，可以借用tomcat中的例子。现将该例子的程序节选如下：
package filters; 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; import javax.servlet.UnavailableException; public class SetCharacterEncodingFilter implements Filter { //可以理解为默认编码，在web.xml中配置后读取存入 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 { // Conditionally select and set the character encoding to be used //如果被忽略或者请求未设置编码，为了防止乱码，进行编码过滤 if (ignore || (request.getCharacterEncoding() == null)) { //设置请求编码为web.xml中配置的编码类型 String encoding = selectEncoding(request); if (encoding != null) request.setCharacterEncoding(encoding); } // Pass control on to the next filter //由FilterChain进行过滤处理，而不是该Filter chain.doFilter(request, response); } //主要从配置文件中读取配置项并进行赋值 public void init(FilterConfig filterConfig) throws ServletException { this.filterConfig = filterConfig; //从web.xml读取配置的编码，如gbk，utf－8等，赋值给encoding this.encoding = filterConfig.getInitParameter("encoding"); //从web.xml读取是否忽略 String value = filterConfig.getInitParameter("ignore"); if (value == null) this.ignore = true; else if (value.equalsIgnoreCase("true")) this.ignore = true; else if (value.equalsIgnoreCase("yes")) this.ignore = true; else this.ignore = false; } protected String selectEncoding(ServletRequest request) { return (this.encoding); } } <filter> <filter-name>Set Character Encoding</filter-name> <filter-class>filters.SetCharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>Set Character Encoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>