SpringBoot过滤器与拦截器使用方法深入分析

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import org.springframework.stereotype.Component;
@Component
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("初始化拦截器");
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        //做一些处理
        System.out.println("doSomeThing");
        chain.doFilter(request,response);
    }
    @Override
    public void destroy() {
        System.out.println("销毁拦截器");
    }
}

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
@Component
public class UserInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle");
        String userName=request.getParameter("username");
        String password = request.getParameter("password");
        if (userName==null||password==null){
            response.setStatus(500);
            response.setContentType("text/html; charset=UTF-8");
            response.getWriter().print("参数缺失");
            return false;
        }
        //进行用户校验
        if (userName.equals("admin")&&password.equals("admin")){
            return true;
        }else {
            response.setStatus(500);
            response.setContentType("text/html; charset=UTF-8");
            response.getWriter().print("用户名或密码错误");
            return false;
        }
    }
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle");
    }
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion");
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class MvcConfig implements WebMvcConfigurer {
    @Autowired
    private UserInterceptor userInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(userInterceptor)
                .addPathPatterns("/**")
                .excludePathPatterns("/error");
    }
}