[JSP] filter

Filter

순서
1.Filter 클래스
2.web.xml
3.jsp, servlet

1.filter class
import java.io.*;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class SimpleFilter implements Filter {

 
 public void destroy() {
  // TODO Auto-generated method stub
 }

 @Override
 public void doFilter(ServletRequest request, ServletResponse response,
   FilterChain chain) throws IOException, ServletException {

  System.out.println("이제 곧 웹 컴포넌트가 시작될 것입니다.");
  chain.doFilter(request, response);  //중간에 다른 페이지 호출
  System.out.println("이제 막 웹컴포넌트가 완료되었습니다.");  //마지막으로 실행하고 종료
 }

 @Override
 public void init(FilterConfig arg0) throws ServletException {
  // TODO Auto-generated method stub
 }

}

2.web.xml

  <filter>--필터
    <filter-name>simplefilter</filter-name>
    <filter-class>filter.SimpleFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>simplefilter</filter-name>
    <url-pattern>/*</url-pattern>--필터를 지정할 범위 검색해볼 것(전체, 특정 파일 등등)
 --<servlet-name>hello-servlet</servlet-name> 서블릿 이름으로도 사용할 수 있음.

  </filter-mapping>
  <servlet>
   <servlet-name>simpleservlet</servlet-name>
   <servlet-class>filter.SimpleServlet</servlet-class>
  </servlet>
  <servlet-mapping>
   <servlet-name>simpleservlet</servlet-name>
   <url-pattern>/simple</url-pattern>
  </servlet-mapping> 

3.페이지는 아무렇게나