Listener、Filter、Servlet 初始化
阿新 • • 發佈：2018-12-17
- listener、Filter、Servlet都有一個初始化的過程
- 那麼它們的初始化順序是: listener > Filter > Servlet;
- servlet初始化
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; public class TestFilter implements Filter{ public void init(FilterConfig filterConfig) throws ServletException { System.out.println("Filter 初始化。。。"); } public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("doFilter 。。。"); chain.doFilter(request, response); } public void destroy() { System.out.println("Filter 銷燬。。。"); } } -
filter初始化
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; public class TestFilter implements Filter{ public void init(FilterConfig filterConfig) throws ServletException { System.out.println("Filter 初始化。。。"); } public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("doFilter 。。。"); chain.doFilter(request, response); } public void destroy() { System.out.println("Filter 銷燬。。。"); } } -
Listener 初始化
import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class TestListener implements ServletContextListener{ public void contextInitialized(ServletContextEvent arg0) { System.out.println("Listener 初始化。。。"); } public void contextDestroyed(ServletContextEvent arg0) { System.out.println("Listener 銷燬。。。"); } }
web.xml<servlet> <servlet-name>s</servlet-name> <servlet-class>com.zm.test.TestServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>s</servlet-name> <url-pattern>/login</url-pattern> </servlet-mapping> <filter> <filter-name>f</filter-name> <filter-class>com.zm.test.TestFilter</filter-class> </filter> <filter-mapping> <filter-name>f</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <listener> <listener-class>com.zm.test.TestListener</listener-class> </listener>