重温servlet②

重定向：我给服务器请求一条消息，服务器让我访问另外一个服务器（新的地址）。302状态码，并设置location头，完成重定向。两个请求。

package com.pcx.servlets;

 

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

 

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import org.apache.commons.io.IOUtils;

 

/**

* @author 平常心cz

*测试io流

*/

public class Gservlet extends HttpServlet {

    /**

     *

     */

    private static final long serialVersionUID = 1L;

 

    public void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        /**

         * 发送文字

         */

//        String s="hello Response";

//        byte[] bytes=s.getBytes();

//        

//        response.getOutputStream().write(bytes);

        

        /**

         * 发送图片

         */

        String path ="D:/a.jpg";

        FileInputStream in=new FileInputStream(new File(path));

        byte[] bytes=IOUtils.toByteArray(in);

        response.getOutputStream().write(bytes);

    }

 

}

 

 

    public void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        /**

         * 设置重定向

         * 1设置location

         * 2设置302状态码

         */

//        response.setHeader("Location", "/zuoye/hello100.jsp");

//        response.setStatus(302);

        

        /**

         * 快捷的重定向

         */

        response.sendRedirect("http:www.baidu.com");

    }

Request

 

    /*

     * 适用referer 来防盗链

     */

    public void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        String referer=request.getHeader("Referer");

        System.out.println(referer);

        if (referer==null||!(referer.contains("localhost"))) {

            System.out.println("hello");

        }else {

            response.sendRedirect("http://www.baidu.com");

        }

    }

 

 

/**

* @author 平常心cz

*测试request的获取url

*/

public class Dservlet extends HttpServlet {

    

    public void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        response.getWriter().print(request.getScheme()+"<br/>");//获取请求协议

        response.getWriter().print(request.getServerName()+"<br/>");//获取服务器的名称

        response.getWriter().print(request.getServerPort()+"<br/>");//获取服务器的端口号

        response.getWriter().print(request.getServletContext()+"<br/>");//获取项目名

        response.getWriter().print(request.getServletPath()+"<br/>");//获取servlet的路径

        response.getWriter().print(request.getQueryString()+"<br/>");//获取请求的参数

        response.getWriter().print(request.getRequestURI()+"<br/>");//获取请求的uri

        response.getWriter().print(request.getRequestURL()+"<br/>");//获取请求的url

    }

 

}

 

 

package com.pcx.servlets;

 

import java.io.IOException;

import java.util.Arrays;

import java.util.Enumeration;

import java.util.Map;

 

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

/**

* @author 平常心cz

*测试request获取请求参数

*/

public class Fservlet extends HttpServlet {

 

    public void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        System.out.println(request.getParameter("xxx"));

        System.out.println(request.getParameter("yyy"));

    }

 

    public void doPost(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        String username=request.getParameter("username");

        String password=request.getParameter("password");

        String[] hobbys=request.getParameterValues("hobby");

        System.out.println(username+" "+password+" "+Arrays.toString(hobbys));

        

        /**

         * 测试获取多个参数名称

         */

        Enumeration names=request.getAttributeNames();

        while(names.hasMoreElements()){

            System.out.println(names.nextElement());

        }

        

        /**

         * 获取所有的参数 并封装到map中

         */

        Map<String, String[]>map=request.getParameterMap();

        System.out.println(map);

        for (String name : map.keySet()) {

            String [] values=map.get(name);

            System.out.println(name+"="+Arrays.toString(values));

        }

    }

 

}