还不知道过滤器或者拦截器的区别吗？
下面我们就来看看吧！
直接上实例。
maven依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.3.5.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!-- Mock测试使用的json-path依赖 -->
<dependency>
<groupId>com.jayway.jsonpath</groupId>
<artifactId>json-path</artifactId>
</dependency>
</dependencies>
创建一个springboot启动类，Application
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
创建一个Controller
@RestController
public class TestController {
@RequestMapping(\"test1\")
public Object test(@RequestParam(\"ids\") List<Integer> ids,HttpServletResponse response) {
System.out.println(\"request param:\"+ids);
return ids;
}
}
创建一个类 实现Filter接口（注意Filter是javax.servlet.Filter）
@Component
public class TestFilter implements Filter{
//这个方法只是在容器启动的时候执行
@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println(\"filter init\");
}
//每个请求 进来和返回 都会经过这
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
System.out.println(\"filter doFilter \");
chain.doFilter(request, response);
}
//容器销毁的时候调用
@Override
public void destroy() {
System.out.println(\"filter destory\");
}
}
创建类实现接口HandlerInterceptor
@Component
public class TestInterceptor implements HandlerInterceptor{
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
System.out.println(\"interceptor preHandle\");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
System.out.println(\"interceptor postHandle\");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception {
System.out.println(\"interceptor afterCompletion\");
}
}
加入拦截器到配置中
@Configuration
public class WebMvcConfiguration extends WebMvcConfigurerAdapter {
@Autowired
private TestInterceptor testInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
//指定拦截器，指定拦截路径
registry.addInterceptor(testInterceptor).addPathPatterns(\"/**\");
}
}
运行程序，然后访问http://localhost:8080/test1?ids=1
控制台打印
filter init
filter doFilter
interceptor preHandle
request param:[1]
interceptor postHandle
interceptor afterCompletion
filter doFilter
HandlerInterceptor接口三个方法：
- preHandle：在执行具体controller方法之前调用
- postHandle：在方法的返回之前(return)调用
- afterCompletion：方法返回后调用
Filter接口三个方法：
init:容器启动就执行
doFilter:有请求进行或者响应都会执行(如果不执行chain.doFilter(request, response)，就表示被过滤后，后面就不会执行，直接返回了)
destory:容器销毁前执行
结合上面的控制台输入，有请求进来时，这六个方法的执行顺序应该是：
Filter#init -> Filter#doFilter -> Interceptor#preHandler ->具体的方法处理 -> Interceptor#postHandle ->Interceptor#afterCompletion ->Filter#doFilter -> Filter#destory
区别总结
1.Filter是Servlet容器的，Interceptor是SpringMvc实现的(结合springBoot看)
2.Filter对所有请求起作用，Intercptor可以设置拦截规则，而且只对经过DispatchServlet的请求起作用。
3.Filter只能拿到request和response，interceptor可以拿到整个请求上下文，包括request和response。
4.Filter是基于函数回调，Interceptor是基于反射(AOP思想)