springmvc字符编码过滤器CharacterEncodingFilter的使用

 <!-- characterEncodingFilter字符编码过滤器 -->
 <filter>
  <filter-name>characterEncodingFilter</filter-name>
  <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
  <init-param>
   <!--要使用的字符集，一般我们使用UTF-8(保险起见UTF-8最好)-->
   <param-name>encoding</param-name>
   <param-value>UTF-8</param-value>
  </init-param>
  <init-param>
   <!--是否强制设置request的编码为encoding，默认false，不建议更改-->
   <param-name>forceRequestEncoding</param-name>
   <param-value>false</param-value>
  </init-param>
  <init-param>
   <!--是否强制设置response的编码为encoding，建议设置为true，下面有关于这个参数的解释-->
   <param-name>forceResponseEncoding</param-name>
   <param-value>true</param-value>
  </init-param>
 </filter>
 <filter-mapping>
  <filter-name>characterEncodingFilter</filter-name>
  <!--这里不能留空或者直接写 ' / ' ，否者不起作用-->
  <url-pattern>/*</url-pattern>
 </filter-mapping>

private String encoding; //要使用的字符集，一般我们使用UTF-8(保险起见UTF-8最好)
private boolean forceRequestEncoding = false; //是否强制设置request的编码为encoding
private boolean forceResponseEncoding = false; //是否强制设置response的编码为encoding

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        String encoding = getEncoding();
        if (encoding != null) { //如果设置了encoding的值，则根据情况设置request和response的编码
         //若设置request强制编码或request本身就没有设置编码
         //则设置编码为encoding表示的值
            if (isForceRequestEncoding() || request.getCharacterEncoding() == null) { 
                request.setCharacterEncoding(encoding);
            }
         //若设置response强制编码，则设置编码为encoding表示的值
            if (isForceResponseEncoding()) { //请注意这行代码，下面有额外提醒
                response.setCharacterEncoding(encoding);
            }
        }
        filterChain.doFilter(request, response);
    }

# 额外提醒
if (isForceResponseEncoding()) { 
 response.setCharacterEncoding(encoding);
}

filterChain.doFilter(request, response);

<Connector URIEncoding="UTF-8" port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" />

org.springframework.web.filter.CharacterEncodingFilter

<!-- ================start 配置spring的字符编码过滤器================ -->    
    <filter>
        <!-- 解决post乱码问题需要配置spring编码过滤器 -->
        <filter-name>characterEncoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>characterEncoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
<!-- ================end 配置spring的字符编码过滤器================ -->