全局编码过滤器

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;

public class EncodingFilter implements Filter {

    private static String encoding;
    private static final String DEFAULT_CHARSET="UTF-8";
    @Override
    public void destroy() {
        System.out.println("--------destroy---------");
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        System.out.println("--------doFilter---------");
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        HttpServletResponse httpResponse=(HttpServletResponse)response;
        if("GET".equals(httpRequest.getMethod())){
            EncodingHttpServletRequest wrapper = new EncodingHttpServletRequest(httpRequest, encoding);
            chain.doFilter(wrapper, response);
        }else{
            httpRequest.setCharacterEncoding(encoding);
            httpResponse.setContentType("text/html;charset="+encoding);
            chain.doFilter(request, response);
        }
    }
    private static class  EncodingHttpServletRequest extends HttpServletRequestWrapper{
         private HttpServletRequest request;
         public EncodingHttpServletRequest(HttpServletRequest request,String encoding) {
           super(request);
           this.request = request;
         }
         @Override
        public String getParameter(String name) {
               String value = request.getParameter(name);
               try {
                value = new String(value.getBytes("iso8859-1"), encoding);
               } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
               }
               return super.getParameter(name);
        }
    }
    @Override
    public void init(FilterConfig config) throws ServletException {
         System.out.println("--------init---------");
         encoding = config.getInitParameter("encoding");
         if(encoding==null||"".equals(encoding))
             encoding=DEFAULT_CHARSET;
    }

}

<!-- 设置全局的编码格式，针对get，post请求，默认编码为UTF-8 -->
  <filter>
      <filter-name>characterFilter</filter-name>
      <filter-class>com.mscncn.jsd1404.EncodingFilter</filter-class>
      <init-param>
          <param-name>encoding</param-name>
          <param-value>UTF-8</param-value>
      </init-param>
  </filter>
  <filter-mapping>
      <filter-name>characterFilter</filter-name>
      <!-- 拦截所有的请求,为所有的请求设置编码 -->
      <url-pattern>/*</url-pattern>
  </filter-mapping>