SpringBoot(8) SpringBoot過濾器Filter
摘要：
1、SpringBoot啟動預設載入的Filter
characterEncodingFilter
hiddenHttpMethodFilter
httpPutFormContentFilter
requestContextFilter
2、Filter優先順序（Order...
1、SpringBoot啟動預設載入的Filter
characterEncodingFilter
hiddenHttpMethodFilter
httpPutFormContentFilter
requestContextFilter
2、Filter優先順序（Ordered.HIGHEST_PRECEDENCE Ordered.LOWEST_PRECEDENCE）
低位值意味著更高的優先順序 Higher values are interpreted as lower priority
自定義Filter，避免和預設的Filter優先順序一樣，不然會衝突
3、自定義Filter
1）使用Servlet3.0的註解進行配置
2）啟動類裡面增加 @ServletComponentScan，進行掃描
3）新建一個Filter類，implements Filter，並實現對應的介面
4) @WebFilter 標記一個類為filter，被spring進行掃描，urlPatterns：攔截規則，支援正則
5）控制chain.doFilter的方法的呼叫，來實現是否通過放行 不放行，web應用resp.sendRedirect("/index.html");
場景：許可權控制、使用者登入(非前端後端分離場景)等
1 @WebFilter(urlPatterns = "/api/*", filterName = "loginFilter")
2 public class LoginFilterimplements Filter{
3
4
5
6/**
7* 容器載入的時候呼叫
8*/
9@Override
10public void init(FilterConfig filterConfig) throws ServletException {
11System.out.println("init loginFilter");
12}
13
14
15/**
16* 請求被攔截的時候進行呼叫
17*/
18@Override
19public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
20System.out.println("doFilter loginFilter");
21
22HttpServletRequest req = (HttpServletRequest) servletRequest;
23HttpServletResponse resp = (HttpServletResponse) servletResponse;
24String username = req.getParameter("username");
25
26if ("admin".equals(username)) {
27filterChain.doFilter(servletRequest,servletResponse);
28} else {
29resp.sendRedirect("/index.html");
30return;
31}
32
33}
34
35/**
36* 容器被銷燬的時候被呼叫
37*/
38@Override
39public void destroy() {
40System.out.println("destroy loginFilter");
41}
42
43 }
啟動日誌裡，已經啟動預設載入的Filter和自定義的Filter
官網地址：https://docs.spring.io/spring-boot/docs/2.1.0.BUILD-SNAPSHOT/reference/htmlsingle/#boot-features-embedded-container-servlets-filters-listeners