对于register a filter using Spring，我们大致有四种不同的选择。
首先，我们可以创建一个 Spring bean 实现 Filter 或扩展 HttpFilter：
@Component
public class MyFilter extends HttpFilter {
@Override
protected void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
throws IOException, ServletException {
// Implementation details...
chain.doFilter(request, response);
}
}
其次，我们可以创建一个扩展GenericFilterBean的Spring bean：
@Component
public class MyFilter extends GenericFilterBean {
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain)
throws IOException, ServletException {
//Implementation details...
chain.doFilter(currentRequest, servletResponse);
}
}
我们也可以使用 FilterRegistrationBean 类：
@Configuration
public class FilterConfiguration {
private final MyFilter myFilter;
@Autowired
public FilterConfiguration(MyFilter myFilter) {
this.myFilter = myFilter;
}
@Bean
public FilterRegistrationBean<MyFilter> myFilterRegistration() {
FilterRegistrationBean<DateLoggingFilter> filterRegistrationBean = new FilterRegistrationBean<>();
filterRegistrationBean.setFilter(myFilter);
filterRegistrationBean.setUrlPatterns(Collections.singletonList("/*"));
filterRegistrationBean.setDispatcherTypes(DispatcherType.REQUEST);
filterRegistrationBean.setOrder(Ordered.LOWEST_PRECEDENCE - 1);
return filterRegistrationBean;
}
}
最后我们可以将 @WebFilter 注释与 @ServletComponentScan 一起使用：
@WebFilter(urlPatterns = "/*", dispatcherTypes = {DispatcherType.REQUEST})
public class MyFilter extends HttpFilter {
@Override
protected void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
throws IOException, ServletException {
// Implementation details...
chain.doFilter(request, response);
}
}