SpringBoot2.0新特性-WebMvcConfigurer攔截器的使用

1.添加一個攔截器Login1Cpt，源碼如下：

package com.liujy.msb.pub.intercept;

import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.PrintWriter;

@Slf4j
@Component
public class Login1Cpt extends HandlerInterceptorAdapter {
 @Override
 public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
 log.info("enter Login1Cpt.preHandle");
 HttpSession session = request.getSession();
 Integer userId = (Integer)session.getAttribute("user_id");
 if (null != userId) {
 response.setCharacterEncoding("UTF-8");
 response.setContentType("application/json; charset=utf-8");
 try {
 PrintWriter out = null ;
 JSONObject res = new JSONObject();
 res.put("tag1", "tag1");
 out = response.getWriter();
 out.append(res.toString());
 } catch (Exception e) {
 response.sendError(500);
 log.error(e.toString(), e);
 }
 return false;
 }
 return super.preHandle(request, response, handler);
 }
}

2.再添加一個攔截器Login2Cpt，源碼如下：

package com.liujy.msb.pub.intercept;

import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.PrintWriter;

@Slf4j
@Component
public class Login2Cpt extends HandlerInterceptorAdapter {
 @Override
 public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
 log.info("enter LoginCpt2.preHandle");
 HttpSession session = request.getSession();
 Integer userId = (Integer)session.getAttribute("user_id");
 if (null == userId) {
 response.setCharacterEncoding("UTF-8");
 response.setContentType("application/json; charset=utf-8");
 try {
 PrintWriter out = null ;
 JSONObject res = new JSONObject();
 res.put("tag2", "tag2");
 out = response.getWriter();
 out.append(res.toString());
 } catch (Exception e) {
 response.sendError(500);
 log.error(e.toString(), e);
 }
 return false;
 }
 return super.preHandle(request, response, handler);
 }
}

3.添加攔截器配置CptConfig，源碼如下：

package com.liujy.msb.pub.intercept;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import javax.annotation.Resource;

@Configuration
public class CptConfig implements WebMvcConfigurer {
 @Resource
 private Login1Cpt login1Cpt;
 @Resource
 private Login2Cpt login2Cpt;

 @Override
 public void addInterceptors(InterceptorRegistry registry) {
 registry.addInterceptor(login1Cpt).order(1);
 registry.addInterceptor(login2Cpt).order(2);
 }
}

4.執行一個接口，在日志中可以看到執行攔截器的順序。

2018-05-18 17:12:33.088  INFO 12516 --- [nio-8080-exec-2] com.liujy.msb.pub.intercept.Login1Cpt    : enter Login1Cpt.preHandle
2018-05-18 17:12:33.092  INFO 12516 --- [nio-8080-exec-2] com.liujy.msb.pub.intercept.Login2Cpt    : enter LoginCpt2.preHandle

請求響應的結果為第二個攔截器返回內容

{
    "tag2": "tag2"
}

 

注：

registry.addInterceptor(login1Cpt).order(1);
設置攔截器執行順序，值越小越先執行。