过滤器的使用

课程代码：

1：接口实现：

 1 public class CharacterEncodingFilter implements Filter {
 2 
 3     public void init(FilterConfig filterConfig) throws ServletException {
 4 
 5     }
 6 
 7     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
 8         servletRequest.setCharacterEncoding("utf-8");
 9         servletResponse.setCharacterEncoding("utf-8");
10         servletResponse.setContentType("text/html;charset=utf-8");
11 
12         System.out.println("CharacterEncodingFilter执行前。。。");
13         filterChain.doFilter(servletRequest,servletResponse);
14         System.out.println("CharacterEncodingFilter执行后。。。");
15 
16     }
17 
18     public void destroy() {
19 
20     }
21 }
View Code

2：添加映射：

1 <filter>
2         <filter-name>CharacterEncodingFilter</filter-name>
3         <filter-class>com.kuang.filter.CharacterEncodingFilter</filter-class>
4     </filter>
5     <filter-mapping>
6         <filter-name>CharacterEncodingFilter</filter-name>
7         <url-pattern>/servlet/*</url-pattern>
8     </filter-mapping>
View Code

 

注意点：

1：doFilter中filterChain.doFilter一定要写，否则不向下继续执行。

2：添加映射，应该以多添加目录的方式为主。不要为省事，整站过滤。

posted @ 2021-03-24 23:38  现在开始JAVA  阅读(30)  评论(0)    收藏  举报