自动登录与乱码解决工具类filter（需要配置xml）

package com.oracle.filter;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.sql.SQLException;
import java.util.Map;

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.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.oracle.bean.Product;
import com.oracle.service.ProductService;
/**
 * 统一编码
 * @author Administrator
 *
 */
public class EncodingFilter implements Filter {

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		// TODO Auto-generated method stub

	}

	@Override
	public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {
		//1.强转
		HttpServletRequest request=(HttpServletRequest) req;
		HttpServletResponse response=(HttpServletResponse) resp;
		response.setContentType("text/html;charset=utf-8");
		//2.放行
			//	chain.doFilter(new MyRequest(request), response);

		//获取所有cookie
		Cookie[] cookies = request.getCookies();
		Cookie coo=null;
		if (cookies!=null) {
			for(Cookie co:cookies){
				if ("unameAndPassword".equals(co.getName())) {
					coo=co;
				}
				
			}
		}
		//根coo是否为null 判断是否完成自动登录
		if (coo==null) {
			//2.放行
			chain.doFilter(new MyRequest(request), response);
		}else{
			//完成自动登录
			//解析
			String unameAndPassword = coo.getValue();
			String[] split = unameAndPassword.split("@");
			String uname = split[0];
			String password = split[1];
			//查询数据库  返回结果
			try {
				ProductService ps = new ProductService();
				Product user = ps.getProductByUnameAndPssword(uname, password);
				//保证用户在线
				if (user!=null) {
					HttpSession session = request.getSession();
					session.setAttribute("uname", user);
					request.getRequestDispatcher("/2.jsp").forward(request, response);
					//放行
					//2.放行
					chain.doFilter(new MyRequest(request), response);
				     
				}else {
					//2.放行
					chain.doFilter(new MyRequest(request), response);
				}
				
			
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
			
			
		}
	
	}

	@Override
	public void destroy() {
		// TODO Auto-generated method stub

	}

}
class MyRequest extends HttpServletRequestWrapper{
	private HttpServletRequest request;
	private boolean flag=true;
	
	
	public MyRequest(HttpServletRequest request) {
		super(request);
		this.request=request;
	}
	
	@Override
	public String getParameter(String name) {  
		if(name==null || name.trim().length()==0){
			return null;
		}
		String[] values = getParameterValues(name);
		if(values==null || values.length==0){
			return null;
		}
		
		return values[0];
	}
	
	@Override
	/**
	 * hobby=[eat,drink]
	 */
	public String[] getParameterValues(String name) {
		if(name==null || name.trim().length()==0){
			return null;
		}
		Map map = getParameterMap();
		if(map==null || map.size()==0){
			return null;
		}
		
		return map.get(name);
	}
	
	@Override
	/**
	 * map{ username=[tom],password=[123],hobby=[eat,drink]}
	 */
	public Map getParameterMap() {  
		
		/**
		 * 首先判断请求方式
		 * 若为post  request.setchar...(utf-8)
		 * 若为get 将map中的值遍历编码就可以了
		 */
		String method = request.getMethod();
		if("post".equalsIgnoreCase(method)){
			try {
				request.setCharacterEncoding("utf-8");
				return request.getParameterMap();
			} catch (UnsupportedEncodingException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}else if("get".equalsIgnoreCase(method)){
			Map map = request.getParameterMap();
			if(flag){
				for (String key:map.keySet()) {
					String[] arr = map.get(key);
					//继续遍历数组
					for(int i=0;i