拦截器
概念：动态拦截方法调用的机制，eg.权限控制…
区分：拦截器和过滤器：
- 归属不同：Filter属于Servlet技术，Interceptor属于SpringMVC技术
- 拦截内容不同：Filter对所有访问进行增强，Interceptor仅针对SpringMVC的访问进行增强
使用：
1.创建拦截器类，实现`HandlerInterceptor接口
package com.yuan.controller.interceptor;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Component
//定义截器类，实现HandlerInterceptor接口
//注意当前类必须受Spring容器控制
public class ProjectInterceptor implements HandlerInterceptor {
@Override
//原始方法调用前执行的内容
//返回值类型可以拦截控制的执行，true放行，false终止
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
String contentType = request.getHeader("Content-Type");
HandlerMethod hm = (HandlerMethod)handler;
System.out.println("preHandle..."+contentType);
return true;
}
@Override
//原始方法调用后执行的内容
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("postHandle...");
}
@Override
//原始方法调用完成后执行的内容
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("afterCompletion...");
}
}2.在springmvcconfig里扫描到拦截器所在的包
3.配置要拦截的路径
//@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport {
// @Autowired
// @Autowired
private ProjectInterceptor projectInterceptor;
public SpringMvcSupport(ProjectInterceptor projectInterceptor) {
this.projectInterceptor = projectInterceptor;
}
@Override
protected void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(projectInterceptor).addPathPatterns("/books/*","/books");
}
}