JavaEE架构简介与JavaWeb新特性

Posted 2021-01-24 言西早石头侠

Fragment 

　　将一个web应用做成几个部分,然后整合

      创建Fragment项目   然后打包放入Servlet项目中的WEB-INF下的lib中

注解

@WebServlet

@WebServlet(
  initParams= {@WebInitParam(name="test1",value="123"),@WebInitParam(name="test2",value="456")}    ,
  loadOnStartup=0,
  urlPatterns={"/fragment","/test/fragment"}
)

getInitParameter("test1")
getInitParameter("test2")//获得参数   根据名称

 

@WebListner

package com.tanlei.listner;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

@WebListener
public class ServletListner implements ServletContextListener {
     @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("ContextListener contextDestroyed");
    }
     
     
     @Override
    public void contextInitialized(ServletContextEvent sce) {
         System.out.println("ContextListener contextInitialized");
    }
}

 

@WebFilter

 

package com.tanlei.filter;

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;

@WebFilter("/*")
public class TestFilter implements Filter {
   
    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        System.out.println("TestFilter doFilter");
        System.out.println("FilterChain doFilter start");
        arg2.doFilter(arg0, arg1);
        System.out.println("FilterChain doFilter end");
    }
    
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("TestFilter init");
    }
    
    @Override
    public void destroy() {
        System.out.println("TestFilter destroy");
    }

}

 

@Resource