使用filter统一设置编码

1.写一个类EncodingFilter.java,实现javax.servlet.Filter(文件命名做到见名知意)

package com.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 EncodingFilter implements Filter {

    private String encoding = null;
    
    /**
     * 初始化方法,从web.xml中获取配置的初始化参数
     */
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        this.encoding = filterConfig.getInitParameter("encode");
        
    }

    /**
     * 设置编码
     */
    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        HttpServletRequest httpRequest = (HttpServletRequest)request;
        HttpServletResponse httpResponse = (HttpServletResponse)response;
        
        httpRequest.setCharacterEncoding(encoding);
        httpResponse.setCharacterEncoding(encoding);
        
        //调用doFIlter方法,如果还有别的过滤器会自动向下调用
        chain.doFilter(httpRequest, httpResponse);
        
    }

    @Override
    public void destroy() {
        
    }


}

2.配置web.xml,使自定义的过滤器生效(如果有其他的过滤器,请放到最前面)

 <filter>
     <filter-name>encode</filter-name>
     <filter-class>com.filter.EncodingFilter</filter-class>
     <init-param>
         <param-name>encode</param-name>
         <param-value>UTF-8</param-value>
     </init-param>
 </filter>
 <filter-mapping>
     <filter-name>encode</filter-name>
     <url-pattern>/*</url-pattern>
 </filter-mapping>