Interceptor(攔截器)
傳統攔截器的寫法:
SpringBoot實現自定義攔截器方法:
相比springmvc,springboot中攔截器不需要在xml中配置,只需定義攔截器類 implements HandlerInterceptor 和攔截器攔截路徑的配置類extends WebMvcConfigurerAdapter。
第一步創建一個類實現HandlerInterceptor接口,重寫接口的方法,只是多了一個@Component註解,這個註解是爲後面的使用時進行注入。例:
1.SessionInterceptor
package com.example.demo;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Created by 20160216 on 2018/2/8.
*/
public class SessionInterceptor implements HandlerInterceptor
{
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
System.out.println("uri="+request.getRequestURI());
//登錄不做攔截
if(request.getRequestURI().equals("/userbg/login") || request.getRequestURI().equals("/user/login_view"))
{
return true;
}
//驗證session是否存在
Object obj = request.getSession().getAttribute("_session_user");
if(obj == null)
{
response.sendRedirect("/user/login_view");
return false;
}
return true;
}
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
}
}
2.SessionConfiguration
package com.example.demo;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
/**
* Created by 20160216 on 2018/2/8.
*/
@Configuration
public class SessionConfiguration extends WebMvcConfigurerAdapter
{
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(newSessionInterceptor()) //指定攔截器類
.addPathPatterns("/**"); //指定該類攔截的url
}
}
小結:
通過對比我們可以明確的看到,SpringBoot實現自定義攔截器跟傳統不一樣的地方只是將XML配置變更爲JAVA配置而已。
Filter(過慮器)
傳統過慮器的寫法:
SpringBoot實現自定義過慮器方法:
@WebFilter(urlPatterns = "/*")
public class CustomFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
MsgUtils.println("自定義過濾器->doFilter");
filterChain.doFilter(servletRequest, servletResponse);
}
@Override
public void destroy() {
}
}
也可以不要@WebFilter(urlPatterns = "/*")這個註解,另外在Application文件或者另外建立一個配置文件進行配置就可以了。
@Configuration
public class FilterConfig {
@Bean
public FilterRegistrationBean filterRegist() {
FilterRegistrationBean frBean = new FilterRegistrationBean();
frBean.setFilter(new CustomFilter());
frBean.addUrlPatterns("/*");
return frBean;
}
}
如果需要配置多個過濾器,需要添加 registration.setOrder(i);這一句,括號中是優先級,數值越大優先級越高。具體可參考http://blog.csdn.net/mzh1992/article/details/66970924
AOP(面向切面編程)
傳統面向切面編程寫法:
SpringBoot實現自定義面向切面編程方法:
小結
服務器接受到的請求都會被filter首先攔截,並可以預處理request, 而攔截器可以調用IOC容器中的各種依賴,filter就不能獲取註解信息並攔截,因爲它和框架無關,但攔截器不能修改request,filter基於回調函數,我們需要實現的filter接口中doFilter方法就是回調函數,而interceptor則基於java本身的反射機制,而@Aspect與Interceptor的都是基於spring aop的實現,@Aspect粒度更細 。他們的攔截順序:filter—>Interceptor—->@Aspect 、