HttpServlet

- 日理万妓 2022-06-08 09:50 173阅读 0赞

HttpServlet

1) 是一个Servlet，继承自GenericServlet，针对于HTTP协议所定制。

2）在service（）方法中直接把ServletRequest和ServletReponse,转为HttpServletRequest和HttpServletReponse.

并调用了重载的service(HttpServletRequest,HttpServletReponse)。在service(HttpServletRequest,HttpServletReponse)

中获取了请求方式：request.getMethod()，根据请求方式又创建了doXXX()方法。

3）实际开发中，直接继承HttpServlet，并根据请求方式复写doXXX()方法接口。

4）优势：  直接由针对性的覆盖doxxx()方法

直接使用HttpServletRequest，HttpServletReponse，不再需要进行强转。

package com.sa.servlet;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.PrintWriter;
    import java.util.Arrays;
    import java.util.Enumeration;
    import java.util.Map;
    
    import javax.servlet.Servlet;
    import javax.servlet.ServletConfig;
    import javax.servlet.ServletContext;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class LoginServlet2 extends HttpServlet {
         
    
    
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    
    	public void doPost(HttpServletRequest request, HttpServletResponse response)
    			throws IOException {
    		// TODO Auto-generated method stub
            String user=request.getParameter("login");
            String password=request.getParameter("password");
            ServletContext servletContext=request.getServletContext();
            String user2=servletContext.getInitParameter("user");
            String password2=servletContext.getInitParameter("password");
            PrintWriter writer=response.getWriter();
            if(user.equals(user2)&&password.equals(password2)){       	       	
            	writer.println("hello,"+user);
            }else{
            	writer.println("sorry,"+user);
            }
    
    	}
    	
    
    }