看一下HandlerInterceptor接口定义，关于具体的HandlerInterceptor说明大家可以看看源码的官方doc说明，更加深入的了解这个接口，包括其一些实现：
HandlerInterceptor接口
preHandle：controller执行之前调用
postHandle：controller执行之后，且页面渲染之前调用
afterCompletion：页面渲染之后调用，一般用于资源清理操作
看一个demo，自己写一个拦截器实现HandlerInterceptor，重写三个方法，
package com.zhihao.miao;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LogHandlerInterceptor implements HandlerInterceptor {
private Logger logger = LoggerFactory.getLogger(getClass());
//请求执行之前调用
@Override
public boolean preHandle(HttpServletRequest request,HttpServletResponse response, Object handler) throws Exception {
System.out.println("==========preHandle==========" + handler.getClass());
return true;
}
//请求之后，且页面渲染之前调用
@Override
public void postHandle(HttpServletRequest request,HttpServletResponse response, Object handler,ModelAndView modelAndView) throws Exception {
String UserAgent = request.getHeader("User-Agent");
logger.info("UserAgent==="+UserAgent);
String remoteIp = request.getRemoteHost()+","+request.getRequestURI();
logger.info("remoteIp"+remoteIp);
}
//页面渲染之后调用，一般用于资源清理操作
@Override
public void afterCompletion(HttpServletRequest request,HttpServletResponse response, Object handler, Exception ex)
throws Exception {
System.out.println("===========afterCompletion=========");
}
}
写一个类，继承WebMvcConfigurerAdapter抽象类，然后重写addInterceptors方法，并调用registry.addInterceptor注册拦截器并将该类加入到spring容器中，
package com.zhihao.miao;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
@SpringBootConfiguration
public class WebConfiguration extends WebMvcConfigurerAdapter {
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new LogHandlerInterceptor());
}
}
定义一个Controller进行测试：
package com.zhihao.miao;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class UserController {
private Logger logger = LoggerFactory.getLogger(getClass());
@GetMapping("/user/home")
public String home(){
logger.info("user home");
return "user home";
}
}
启动类启动，
package com.zhihao.miao;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class,args);
}
}
访问http://127.0.0.1:8080/user/home
总结：
编写一个拦截器步骤：
- 写一个拦截器，实现HandlerInterceptor接口
- 写一个类，继承WebMvcConfigurerAdapter抽象类，然后重写addInterceptors方法，并调用registry.addInterceptor注册自定义的拦截器。
