补充:SpringBoot启动日志
1、深入SpringBoot2.x过滤器Filter和使用Servlet3.0配置自定义Filter实战(核心知识)
简介:讲解SpringBoot里面Filter讲解和使用Servlet3.0配置自定义Filter实战
filter简单理解:人--->检票员(filter)---> 景点
1、SpringBoot启动默认加载的Filter
characterEncodingFilter
hiddenHttpMethodFilter
httpPutFormContentFilter
requestContextFilter
2、Filter优先级
Ordered.HIGHEST_PRECEDENCE
Ordered.LOWEST_PRECEDENCE
低位值意味着更高的优先级 Higher values are interpreted as lower priority
自定义Filter,避免和默认的Filter优先级一样,不然会冲突
注册Filter的bean FilterRegistrationBean
同模块里面有相关默认Filter
web->servlet->filter
3、自定义Filter
1)使用Servlet3.0的注解进行配置
2)启动类里面增加 @ServletComponentScan,进行扫描
3)新建一个Filter类,implements Filter,并实现对应的接口
4) @WebFilter 标记一个类为filter,被spring进行扫描
urlPatterns:拦截规则,支持正则
5)控制chain.doFilter的方法的调用,来实现是否通过放行
不放行,web应用resp.sendRedirect("/index.html");
场景:权限控制、用户登录(非前端后端分离场景)等
1、官网地址:https://docs.spring.io/spring-boot/docs/2.1.0.BUILD-SNAPSHOT/reference/htmlsingle/#boot-features-embedded-container-servlets-filters-listeners
代码示例:
启动类中加入@ServletComponentScan注解
LoginFilter.java:
package net.xdclass.demo.Filter; import java.io.IOException; import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; @WebFilter(urlPatterns = "/api/*", filterName = "loginFilter")
public class LoginFilter implements Filter{ /**
* 容器加载的时候调用
*/
@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("init loginFilter");
} /**
* 请求被拦截的时候进行调用
*/
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("doFilter loginFilter"); HttpServletRequest req = (HttpServletRequest) servletRequest;
HttpServletResponse resp = (HttpServletResponse) servletResponse;
String username = req.getParameter("username"); if ("xdclass".equals(username)) {
filterChain.doFilter(servletRequest,servletResponse);
} else {
resp.sendRedirect("/index.html");
return;
} } /**
* 容器被销毁的时候被调用
*/
@Override
public void destroy() {
System.out.println("destroy loginFilter");
} }
controller:
浏览器输入:http://localhost:8083/api/v1/account?username=xdclass
前台显示:
控制台显示:
输入错误的username情况:
浏览器输入:http://localhost:8083/api/v1/account?username=xdclasss
跳转到index.html(可用于提示用户进行登录操作)