SpringBoot2.x過濾器Filter和使用Servlet3.0配置自定義Filter實戰
補充:SpringBoot啟動日誌
1、深入SpringBoot2.x過濾器Filter和使用Servlet3.0配置自定義Filter實戰(核心知識)
簡介:講解SpringBoot裡面Filter講解和使用Servlet3.0配置自定義Filter實戰
filter簡單理解:人--->檢票員(filter)---> 景點
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
註冊Filter的bean FilterRegistrationBean
同模組裡面有相關預設Filter
web->servlet->filter
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、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
程式碼示例:
啟動類中加入@ServletComponentScan註解
LoginFilter.java:
1 package net.xdclass.demo.Filter; 2 3 import java.io.IOException; 4 5 import javax.servlet.Filter; 6 import javax.servlet.FilterChain; 7 import javax.servlet.FilterConfig; 8 import javax.servlet.ServletException; 9 import javax.servlet.ServletRequest; 10 import javax.servlet.ServletResponse; 11 import javax.servlet.annotation.WebFilter; 12 import javax.servlet.http.HttpServletRequest; 13 import javax.servlet.http.HttpServletResponse; 14 15 16 @WebFilter(urlPatterns = "/api/*", filterName = "loginFilter") 17 public class LoginFilter implements Filter{ 18 19 20 21 /** 22 * 容器載入的時候呼叫 23 */ 24 @Override 25 public void init(FilterConfig filterConfig) throws ServletException { 26 System.out.println("init loginFilter"); 27 } 28 29 30 /** 31 * 請求被攔截的時候進行呼叫 32 */ 33 @Override 34 public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 35 System.out.println("doFilter loginFilter"); 36 37 HttpServletRequest req = (HttpServletRequest) servletRequest; 38 HttpServletResponse resp = (HttpServletResponse) servletResponse; 39 String username = req.getParameter("username"); 40 41 if ("xdclass".equals(username)) { 42 filterChain.doFilter(servletRequest,servletResponse); 43 } else { 44 resp.sendRedirect("/index.html"); 45 return; 46 } 47 48 49 50 } 51 52 /** 53 * 容器被銷燬的時候被呼叫 54 */ 55 @Override 56 public void destroy() { 57 System.out.println("destroy loginFilter"); 58 } 59 60 }
controller:
瀏覽器輸入:http://localhost:8083/api/v1/account?username=xdclass
前臺顯示:
控制檯顯示:
輸入錯誤的username情況:
瀏覽器輸入:http://localhost:8083/api/v1/account?username=xdclasss
跳轉到index.html(可用於提示使用者進行登入操作)