java servlet拾遗（5）-过滤器

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/order/*")
public class MyFilter implements Filter {
	
	public void doFilter(ServletRequest req, ServletResponse res,FilterChain filter) throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest) req;//一般发布为http应用，可以直接转换为HttpServletRequest
		HttpServletResponse response = (HttpServletResponse) res;//一般发布为http应用，可以直接转换为HttpServletResponse
		
		//TODO 前置预处理1
		
		filter.doFilter(request, response);
		
		//TODO 后置处理
	}
	
	@Override
	public void init(FilterConfig config) throws ServletException {
		//做一些启动配置
	}
	@Override
	public void destroy() {
		//做一些容器销毁时垃圾回收
	}
}