/**
 * Tomcat GET方式表单提交乱码解决。
 * @author BeanSoft
 *
 */
public class TomcatFormFilter implements Filter {
 public void destroy() {
  // TODO Auto-generated method stub
  
 }

 public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
  // 1. ServletRequest 转成 HttpServletRequest
  HttpServletRequest req = (HttpServletRequest)request;
  
  // 2. 如果是GET，就生成一个Wrapper对象，覆盖获取参数的方法进行转码
  if("GET".equalsIgnoreCase(req.getMethod())) {
   req = new MyRequest(req);
  }
  // 3. 如果是POST，request.setCharacterEncoding("UTF-8")
  else if("POST".equalsIgnoreCase(req.getMethod())) {
   req.setCharacterEncoding("UTF-8");
  }
  // 4.调用chain.doFilter继续向后执行
  chain.doFilter(req, response);
 }

 public void init(FilterConfig arg0) throws ServletException {
  // TODO Auto-generated method stub
  
 }

}

/**
 * 包装器，覆盖 getParameter()和 getParameterValues() 这两个方法来进行转码。
 * @author BeanSoft
 *
 */
class MyRequest extends HttpServletRequestWrapper {

 public MyRequest(HttpServletRequest request) {
  super(request);
  // TODO Auto-generated constructor stub
 }
 
 /**
  * 字符串转码。
  * @param input 输入字符串
  * @param srcEncoding 源字符串的编码
  * @param targetEncoding 目标编码
  * @return 转换过的内容
  */
 public String changeEncoding(String input, String srcEncoding, String targetEncoding) {
  try {
   // 1. 获取源编码的bytes[]
   byte[] data = input.getBytes(srcEncoding);
   // 2. 将bytes[]按照制定编码转换为String
   return new String(data, targetEncoding);
  } catch (UnsupportedEncodingException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  
  return input;
 }

 @Override
 public String getParameter(String name) {
  String value = super.getParameter(name);
  
  if(value != null) {
   value = changeEncoding(value, "ISO8859-1", "UTF-8");
  }
  return value;
 }

 @Override
 public String[] getParameterValues(String name) {
  String[] values = super.getParameterValues(name);
  if(values != null && values.length > 0) {
   for (int i = 0; i < values.length; i++) {
    String value = values[i];
    
    values[i] = changeEncoding(value, "ISO8859-1", "UTF-8");
   }
  }
  return values;
 }
 
}