一、過濾器
首先在啓動類加註解
@SpringBootApplication
@ServletComponentScan //用於進行servlet組件掃描
public class Springboot03Application {
public static void main(String[] args) {
SpringApplication.run(Springboot03Application.class, args);
}
}
/**
* 基於servlet3.x版本的過濾器,所以需要使用註解
*/
@WebFilter(urlPatterns = "/api/*", filterName = "loginFilter")
public class UserFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("初始化操作-----------");
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse) servletResponse;
//獲取用戶名
String name = request.getParameter("name");
//如果獲取的用戶名與給定的用戶名相同,則放行
if("jack".equals(name)){
filterChain.doFilter(servletRequest,servletResponse);//如果當前名字是Jack,則放行
}else{
response.sendRedirect("/login.html");
}
}
@Override
public void destroy() {
System.out.println("銷燬操作-------");
}
}
二、自定義攔截器
- 1、自定義攔截器類,實現
HandlerInterceptor
接口
preHandle :調用Controller某個方法之前
postHandle :Controller之後調用,視圖渲染之前,若控制器Controller出現異常,則不執行此方法
afterCompletion :不管有沒有異常,這個afterCompletion都會被調用,用於資源清理
@Component
public class LoginInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("preHandle");
return true; //false代表攔截 true代表放行
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("postHandle");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("afterCompletion");
}
}
- 2、自定義類加註解
@Configuration
並實現 WebMvcConfigurer 接口類,重寫addInterceptors(){}
/**
* 自定義攔截器
*/
@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
@Autowired
private LoginInterceptor loginInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
System.out.println("addInterceptors");
registry.addInterceptor(loginInterceptor).addPathPatterns("/api/*/**");
}
}
- 3、將1中的自定義攔截器加入到步驟2中的addInterceptors(){}方法中。
附:攔截器失效原因:
1)檢查是否有註解@Configuration
2)攔截路徑是否有 ** 和 *
3)攔截器最後路徑一定要是 “/**”, 如果是目錄的話則是 /*/
三、模板引擎 thymeleaf 與 freemark
- Freemarker Template Lanaguage (FTL) 文件後綴是.ftl
特點:嚴格依賴MVC模式,不依賴Servlet容器。不消耗性
基礎配置:
#freemarker基礎配置
# 是否開啓thymeleaf緩存,本地爲false,生產建議爲true
spring.freemarker.cache=false
spring.freemarker.charset=UTF-8
spring.freemarker.allow-request-override=false
spring.freemarker.check-template-location=true
#類型
spring.freemarker.content-type=text/html
spring.freemarker.expose-request-attributes=true
spring.freemarker.expose-session-attributes=true
#文件後綴
spring.freemarker.suffix=.ftl
#路徑
spring.freemarker.template-loader-path=classpath:/templates/
引入freemarker模板引擎的依賴
<!-- 引入freemarker模板引擎的依賴 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-freemarker</artifactId>
</dependency>
- Thymeleaf(springboot 主推)
特點:輕量級模板引擎,頁面有複雜業務,不推薦使用。比如頁面有很多個判斷(會導致解析DOM或者XML佔用過多內存)。
基礎配置:
#thymeleaf基礎配置
#開發時關閉緩存,不然沒法看到實時頁面
spring.thymeleaf.cache=false
spring.thymeleaf.mode=HTML5
#前綴
spring.thymeleaf.prefix=classpath:/templates/
#編碼
spring.thymeleaf.encoding=UTF-8
#類型
spring.thymeleaf.servlet.content-type=text/html
#名稱的後綴
spring.thymeleaf.suffix=.html
引入thymeleaf相關maven依賴
<!--thymeleaf相關maven依賴-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>