Java WEB应用中文乱码处理总结

package com.cdu.yige.filter;
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.http.HttpServletRequest;

public class EncodingFilter implements Filter {
     private String charset = "UTF-8";
     @Override
     public void destroy() {}
     @Override
     public void doFilter(ServletRequest request, ServletResponse response,
               FilterChain chain) throws IOException, ServletException {
          HttpServletRequest req = (HttpServletRequest) request;
          if(req.getMethod().equalsIgnoreCase("GET")) {
               if(!(req instanceof GetRequest)) {
                    req = new GetRequest(req, charset);//处理get请求编码
               }
          } else {
               req.setCharacterEncoding(charset);//处理post请求编码
          }
          chain.doFilter(req, response);
     }

     @Override
     public void init(FilterConfig fConfig) throws ServletException {
          String charset = fConfig.getInitParameter("charset");
          if(charset != null && !charset.isEmpty()) {
               this.charset = charset;
          }
     }
}

package com.cdu.yige.filter;
import java.io.UnsupportedEncodingException;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
/**
* 对GET请求参数加以处理！
* @author lucien
*
*/
public class GetRequest extends HttpServletRequestWrapper {
     private HttpServletRequest request;
     private String charset;
     
     public GetRequest(HttpServletRequest request, String charset) {
          super(request);
          this.request = request;
          this.charset = charset;
     }

     @Override
     public String getParameter(String name) {
          // 获取参数
          String value = request.getParameter(name);
          if(value == null) return null;//如果为null，直接返回null
          try {
               // 对参数进行编码处理后返回
               return new String(value.getBytes("ISO-8859-1"), charset);
          } catch (UnsupportedEncodingException e) {
               throw new RuntimeException(e);
          }
     }
     
     @SuppressWarnings({ "unchecked", "rawtypes" })
     @Override
     public Map getParameterMap() {
          Map<String,String[]> map = request.getParameterMap();
          if(map == null) return map;
          // 遍历map，对每个值进行编码处理
          for(String key : map.keySet()) {
               String[] values = map.get(key);
               for(int i = 0; i < values.length; i++) {
                    try {
                         values[i] = new String(values[i].getBytes("ISO-8859-1"), charset);
                    } catch (UnsupportedEncodingException e) {
                         throw new RuntimeException(e);
                    }
               }
          }
          // 处理后返回
          return map;
     }
     @Override
     public String[] getParameterValues(String name) {
          String[] values = super.getParameterValues(name);
          for(int i = 0; i < values.length; i++) {
               try {
                    values[i] = new String(values[i].getBytes("ISO-8859-1"), charset);
               } catch (UnsupportedEncodingException e) {
                    throw new RuntimeException(e);
               }
          }
          return values;
     }
}