SpringMVC自定义拦截器

深藏阁楼爱情的钟 2022-03-15 06:16 327阅读 0赞

![20190301103457370.gif][]![20190301103457370.gif][]**概念**![20190301103457370.gif][]![20190301103457370.gif][]

1.跟过滤器比较像的技术.

2.发送请求时被拦截器拦截,在控制器的前后添加额外功能.

2.1 跟 AOP 区分开.AOP 在特定方法前后扩充(对 ServiceImpl)  
             2.2 拦截器,请求的拦截.针对点是控制器方法.(对 Controller)  
3.SpringMVC 拦截器和 Filter 的区别  
              3.1 拦截器只能拦截器 Controller  
              3.2 Filter 可以拦截任何请求.

4.实现自定义拦截器的步骤:

4.1 新建类实现 HandlerInterceptor

public class DemoInterceptor implements
    HandlerInterceptor {
    //在进入控制器之前执行
    //如果返回值为 false,阻止进入控制器
    //控制代码
    @Override
    public boolean preHandle(HttpServletRequest arg0,
    HttpServletResponse arg1, Object arg2) throws Exception
    {
    System.out.println("arg2:"+arg2);
    System.out.println("preHandle");
    return true;
    }
    //控制器执行完成,进入到 jsp 之前执行.
    //日志记录.
    //敏感词语过滤
    @Override
    public void postHandle(HttpServletRequest arg0,
    HttpServletResponse arg1, Object arg2, ModelAndView
    arg3)
    throws Exception {
    System.out.println("往"+arg3.getViewName()+"跳转
    ");
    System.out.println("model 的值
    "+arg3.getModel().get("model"));
    String word =
    arg3.getModel().get("model").toString();
    String newWord = word.replace("祖国", "**");
    arg3.getModel().put("model", newWord);
    // arg3.getModel().put("model", "修改后的内容");
    System.out.println("postHandle");
    }
    //jsp 执行完成后执行
    //记录执行过程中出现的异常.
    //可以把异常记录到日志中
    @Override
    public void afterCompletion(HttpServletRequest arg0,
    HttpServletResponse arg1, Object arg2, Exception arg3)
    throws Exception {
    System.out.println("afterCompletion"+arg3.getMessag
    e());
    }
    }

4.2 在 springmvc.xml 配置拦截器需要拦截哪些控制器  
              4.2.1 拦截所有控制器

<mvc:interceptors>
    <bean
    class="com.bjsxt.interceptor.DemoInterceptor"></bean>
    </mvc:interceptors>

4.2.2 拦截特定的的 url

<mvc:interceptors>
    <mvc:interceptor>
    <mvc:mapping path="/demo"/>
    <mvc:mapping path="/demo1"/>
    <mvc:mapping path="/demo2"/>
    <bean
    class="com.*.interceptor.DemoInterceptor"></bean>
    </mvc:interceptor>
    </mvc:interceptors>

**二. 拦截器栈**  
1. 多个拦截器同时生效时,组成了拦截器栈  
2. 顺序:先进后出. 3. 执行顺序和在 springmvc.xml 中配置顺序有关  
4. 设置先配置拦截器 A 在配置拦截器 B 执行顺序为  
preHandle(A) --> preHandle(B) --> 控制器方法 --> postHandle(B) --> postHanle(A) --> JSP --> afterCompletion(B) --> afterCompletion(A)

![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]![20190301103457370.gif][]

[20190301103457370.gif]: /images/20220315/26abf6b83b144c50b4e816ea2c2727d1.png