JavaWeb---Filter
先上代码
public class FilterA implements Filter {
public FilterA() {
System.out.println("实例化filterA");
}
public void destroy() {
System.out.println("销毁filterA");
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
System.out.println("经过FilterA的前处理");
chain.doFilter(request, response);
System.out.println("到达filterA的后处理");
}
public void init(FilterConfig fConfig) throws ServletException {
System.out.println("初始化FilterA");
}
}
public class FilterB implements Filter {
public FilterB() {
System.out.println("实例化filterB");
}
public void destroy() {
System.out.println("销毁filterB");
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
System.out.println("经过FilterB的前处理");
chain.doFilter(request, response);
System.out.println("到达filterB的后处理");
}
public void init(FilterConfig fConfig) throws ServletException {
System.out.println("初始化FilterB");
}
}
public class FilterC implements Filter {
public FilterC() {
System.out.println("实例化filterC");
}
public void destroy() {
System.out.println("销毁filterC");
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
System.out.println("经过FilterC的前处理");
chain.doFilter(request, response);
System.out.println("到达filterC的后处理");
}
public void init(FilterConfig fConfig) throws ServletException {
System.out.println("初始化FilterC");
}
}
web.xml的配置顺序(注意顺序)：有先后顺序，而且如果同一个拦截器同时使用注解和web.xml配置会在启动项目时实例化两次
启动服务器：
实例化FilterA
初始化FilterA
实例化FilterB
初始化FilterB
实例化FilterC
初始化FilterC
浏览器访问web应用的test.jsp
经过FilterA的前处理
经过FilterB的前处理
经过FilterC的前处理
到达filterC的后处理
到达filterB的后处理
到达filterA的后处理
