spring中過濾器與攔截器的區別

時間 2021-02-16

標籤 java api 跨域 tomcat app cors 框架 ide 函數 post 欄目 Spring 简体版

原文原文鏈接

攔截器

原理：攔截器是基於java反射機制(動態代理)實現

使用：java

實現HandlerInterceptor接口api

- preHandle：返回值：boolean表示是否須要將當前的請求攔截下來。方法中Object對象標識的是被攔截的請求的目標對象
- postHandle：在DispatcherServlet進行視圖返回渲染以前被調用
- afterCompletion：在DispatcherServlet渲染了對應的視圖以後執行，這個方法的主要做用是用於進行資源清理的工做

具體代碼跨域

/**
 * 註冊攔截器
 */
@SpringBootConfiguration
public class WebConfig  implements WebMvcConfigurer {

    @Autowired
    DataInterceptor dataInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //攔截路徑，表示此路徑下的全部地址都會先執行此攔截器，經過以後才能訪問Controller
        String[] addPathPatterns = {
            "/api/**"
        };
        registry.addInterceptor(dataInterceptor).addPathPatterns(addPathPatterns);
    }
}

/**
 * 新建攔截器
 */
 @Component(value = "dataInterceptor")
public class DataInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
                         Object handler) throws Exception {
    Systemt.out.println("新建攔截器");
    return true;
    }
}

實現WebRequestInterceptor接口tomcat

- preHandle方法無返回值
- postHandle
- afterCompletion

使用場景app
- 使用原則：處理全部請求的共同問題(亂碼問題，權限驗證問題)

過濾器

原理：過濾器是基於函數回調來實現

使用：實現Filter接口cors

具體代碼框架

/**
 * 經過過濾器實現跨域處理
 */
@Order(1)
@Component
@WebFilter(urlPatterns = { "/api/*"}, filterName = "corsFilter")
public class CorsFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {}

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse,     FilterChain filterChain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "*");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers",
            "authorization, authorizationToken, appCode, x-requested-with, Content-Type, Access-Token");
        response.setHeader("Access-Control-Expose-Headers", "*");
        filterChain.doFilter(servletRequest, servletResponse);
}

    @Override
    public void destroy() {}
}