详解Spring中的拦截器与过滤器

public interface Filter {  
//Servlet容器（如Tomcat）在初始化这个Filter时调用，一般用于初始化一些资源  
public default void init(FilterConfig filterConfig) throws ServletException {}  
//这个方法是具体执行过滤器逻辑的方法  
//另外chain变量是过滤器链，可以使用这个变量来决定这个请求是否可以向下流转  
public void doFilter(ServletRequest request, ServletResponse response,  
FilterChain chain) throws IOException, ServletException;  
//Servlet容器（如Tomcat）在关闭前会销毁Filter，一般用于资源的释放  
public default void destroy() {}  
}  

// 过滤器  
package com.example.demo.filter.one;  
@WebFilter(filterName = "filter-one", urlPatterns = "/bad/*")  
public class FilterOne implements Filter {  
@Override  
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {  
//执行Filter逻辑  
System.out.println("这是Filter过滤器1号");  
//让请求继续进入Filter链的下一个节点  
chain.doFilter(request, response);  
}  
}  
// 启动类  
@SpringBootApplication  
@ServletComponentScan(basePackages = "com.example.demo.filter.one")  
public class SpringBootDemoApplication {  
public static void main(String[] args) {  
SpringApplication.run(SpringBootDemoApplication.class, args);  
}  
}  

// 过滤器  
public class FilterTwo implements Filter {  
@Override  
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {  
//执行Filter逻辑  
System.out.println("这是Filter过滤器2号");  
//让请求继续进入Filter链的下一个节点  
chain.doFilter(request, response);  
}  
}  
// 配置类  
@Configuration  
public class FilterConfiguration {  
@Bean  
public FilterRegistrationBean<FilterTwo> filterRegistrationBean() {  
FilterTwo filterTwo = new FilterTwo();  
FilterRegistrationBean<FilterTwo> filterRegistrationBean = new FilterRegistrationBean<>();  
filterRegistrationBean.setFilter(filterTwo);  
//设置过滤器名、过滤规则  
filterRegistrationBean.setName("filter-two");  
filterRegistrationBean.addUrlPatterns("/bad/*");  
return filterRegistrationBean;  
}  
}  

// 过滤器  
@Component  
public class FilterThree implements Filter {  
@Override  
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {  
//执行Filter逻辑  
System.out.println("这是Filter过滤器3号");  
//让请求继续进入Filter链的下一个节点  
chain.doFilter(request, response);  
}  
}  
// 配置类  
@Configuration  
public class FilterConfiguration {  
@Bean  
public DelegatingFilterProxyRegistrationBean delegatingFilterProxyRegistrationBean() {  
DelegatingFilterProxyRegistrationBean delegatingFilterProxyRegistrationBean = new DelegatingFilterProxyRegistrationBean("filterThree");  
delegatingFilterProxyRegistrationBean.setName("filter-three");  
delegatingFilterProxyRegistrationBean.addUrlPatterns("/bad/*");  
return delegatingFilterProxyRegistrationBean;  
}  
}  

public interface HandlerInterceptor {  
//在请求被处理前（到达Controller前）进行处理，如果返回false，那么请求不往下进行  
default boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)  
throws Exception {  
return true;  
}  
//在请求被处理后（执行完Controller逻辑后）进行处理  
default void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,  
@Nullable ModelAndView modelAndView) throws Exception {  
}  
//在页面渲染结束后执行，一般用于资源释放  
default void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,  
@Nullable Exception ex) throws Exception {  
}  
}  

// 拦截器  
@Component  
public class HandlerInterceptorOne implements HandlerInterceptor {  
@Override  
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {  
System.out.println("请求到Controller前-执行 HandlerInterceptor 逻辑");  
return true;  
}  
@Override  
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {  
System.out.println("Controller执行完后-执行 HandlerInterceptor 逻辑");  
}  
@Override  
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {  
System.out.println("返回视图前-执行 HandlerInterceptor 逻辑");  
}  
}  
// 配置类  
@Configuration  
public class InterceptorConfiguration implements WebMvcConfigurer {  
@Autowired  
private HandlerInterceptorOne handlerInterceptorOne;  
@Override  
public void addInterceptors(InterceptorRegistry registry) {  
//这册拦截器  
registry.addInterceptor(handlerInterceptorOne)  
//设置拦截的路径  
.addPathPatterns("/bad/*")  
//设置不拦截的路径（排除这些路径）  
.excludePathPatterns("/bad/test");  
}  
}