过滤器（防止乱码）

package cqvie.yjq.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;
import javax.servlet.http.HttpServletResponse;

public class EncodingFilter1 implements Filter {

    public void destroy() {

    }

    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain chain)
            throws IOException, ServletException {

        //1.首先ServletRequest转换为HttpServletRequest
        HttpServletRequest request = (HttpServletRequest) arg0;
        //2.把ServletResponse转换为HttpServletResponse
        HttpServletResponse response = (HttpServletResponse) arg1;
        //3.得到当前的请求方式
        String method = request.getMethod();
        //4.判断
        if(method.toUpperCase().equals("POST")) {
            //是post请求时，处理乱码
            request.setCharacterEncoding("UTF-8");
            //放行
            chain.doFilter(request, response);
        } else {
            chain.doFilter(request, response);
        }
    }

    public void init(FilterConfig arg0) throws ServletException {

    }

}

<!-- 为了防止乱码，基于web.xml中的部分关于过滤器的配置 -->
<filter>
      <filter-name>EncodingFilter1</filter-name>
      <filter-class>cqvie.yjq.filter.EncodingFilter1</filter-class>
  </filter>
  
  <filter-mapping>
      <filter-name>EncodingFilter1</filter-name>
       <!-- 所有路径的文件 -->
      <url-pattern>/*</url-pattern>
  </filter-mapping>