前情提要
之前的系列篇中介绍了在SpringBoot中使用过滤器,其实拦截器和过滤器从功能上来说,拦截器/过滤器所能实现的功能过滤器/拦截器都能够实现。但是过滤器是java实现的,它需要依赖于Servlet容器,而拦截器是SprignMVC实现的一个机制,独立于Servlet容器,而且能实现IOC容器中的各个bean。简单的说:过滤器的urlPattern针对的是所有的请求,而拦截器的urlPattern针对的SpringMVC中的Controller控制器处理的请求,并不会拦截Servlet容器
使用Interceptor实例
使用Interceptor很简单,分为三个步骤:
1.创建自定义的拦截器并实现HandlerInterceptor接口;
package org.springframework.demo.section;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* 一个简单的Interceptor拦截器类
* @author chengxi
*/
public class MyInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
System.out.println("myinterc prehandler");
return true;
}
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
System.out.println("myinterc posthandler");
}
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
System.out.println("myinterc aftercompletion");
}
}
2.创建一个java类继承WebMvcConfiguraeAdapter并重写addInterceptor方法,该类用来添加配置拦截器:
package org.springframework.demo.section;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
/**
* 继承WebMvcConfigureAdapter继承并重写addInterceptor方法用于添加配置拦截器
* @author chengxi
*/
public class MyAdapter extends WebMvcConfigurerAdapter {
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new MyInterceptor())
.addPathPatterns("/**");
super.addInterceptors(registry);
}
}
3.然后我们需要编写一个Controller控制类用于处理url请求,因为拦截器只能拦截SpringMVC的Controller控制器处理的请求:
package org.springframework.demo.section;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* 一个简单的控制器测试类,主要用于测试Interceptor拦截器的使用
* @author chengxi
*/
@RestController
@RequestMapping("/inter")
public class InterController {
@RequestMapping("/test")
public void test(HttpServletResponse response) throws IOException {
response.getWriter().print("<h1>Hello interceptor test</h1>");
}
}
最后创建一个启动类,直接运行即可,然后打开浏览器:localhost:8080/inter/test
将会看到页面输出Hello interceptor test,即表示拦截器使用成功