response中实现的一些功能

作者: 李霖神谷 | 来源:发表于2017-11-02 17:52 被阅读31次

1.使用response下载图片

import javax.servlet.http.HttpServletResponse;

/**
 * 使用response下载图片
 */
public class DowResponse extends HttpServlet {
    
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //设置http头，实现下载功能，由于请求与响应都要求使用iso8859-1编码，不能出现中文
        //使用url编码方式来解决中文问题将ascii吗里没有的字符转换成ascii有的字符表示的形式
        response.setHeader("Content-Disposition","attachment;filename="+URLEncoder.encode("美女.jpg","utf-8"));
        //设置一个输入流
        InputStream file=new FileInputStream(this.getServletContext().getRealPath("1.jpg"));
        //设置一个向浏览器输出数据的输出流
        OutputStream ofile=response.getOutputStream();
        byte[] bs=new byte[1024];
        int i=0;
        while((i=file.read(bs))!=-1){
            ofile.write(bs,0,i);
        }
        file.close();
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }
}

2.设置浏览器的缓存机制

package Lishuai;

import java.io.IOException;
import java.util.Date;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class NoCaCheResponse
 */
public class NoCaCheResponse extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public NoCaCheResponse() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //浏览器自带内存缓存机制，当设置缓存储存为从不时，当再次访问次页面时，不会更新。
        response.setDateHeader("Expires",System.currentTimeMillis()+1000l*3600*24*30);
        
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().write("当前页面所在时间为："+new Date().toLocaleString());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

3.通过response实现重定向功能：

package Lishuai;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class redirectResponse
 */
public class redirectResponse extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     *response设置重定向
     */
    public redirectResponse() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //response.setStatus(302);
        //response.setHeader("Location","index.jsp");
        //sendRedirect代替以上两句代码
        response.sendRedirect("index.jsp");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

4.通过response实现跳转页面的功能

package Lishuai;

import java.io.IOException;


import java.util.Date;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class reflesh
 */
public class refleshresponse extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public refleshresponse() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //如果不在http响应头设置url就会访问当前页面。
        //response.getWriter().write(new Date().toLocaleString());
        //response.setHeader("Refresh","1");
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().write("你已经注册用户成功，三秒将会跳转页面o");
        response.setHeader("Reflesh","3;url=index.jsp");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

5.设置服务器的编码类型

package Lishuai;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class responds
 */
public class responds extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public responds() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //编码时使用操作系统自带的码表gbk，浏览器也是使用操作系统自带码表，所以当打中文时不会出现乱码现象,当自定义码表时就会出现乱码现象。
        //response.getOutputStream().write("lishuailallal自己哦怕".getBytes("utf-8"));//将字符串传送到response缓冲区内
        //如果将浏览器使用的解码的码表改为u8类型的就不会有乱妈的现象。
        //response.setHeader("Content-Type", "text/html;charset=utf-8");
        //当使用getWriter()向浏览器发送数据时会出现乱码，因为发送数据时服务器会使用iso8859-1来编码
        //将服务器的编码改为utf-8类型
        //response.setCharacterEncoding("utf-8");
        //然而使用一个语句就能代替上面两个语句,当将浏览器设置为utf-8，服务器自动编码为utf-8.
        response.setContentType("text/html;charaset=utf-8");
        response.getWriter().write("李帅");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

6.通过response向浏览器发送验证码图片

package lish;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class yanzheng
 */
public class yanzheng extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public yanzheng() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //1.构造一张图片
        int h=30;
        int w=120;
        int xpyl=5;
        int ypyl=22;
        BufferedImage image=new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);
        //2.获取图像上的画布xpyl
        Graphics2D g=(Graphics2D) image.getGraphics();
        //3.设置背景颜色
        g.setColor(Color.LIGHT_GRAY);
        g.fillRect(0, 0, w, h);
        //4.设置边框
        g.setColor(Color.blue);
        g.drawRect(0, 0, w-1, h-1);
        //5.画干扰线，干扰线要求是随机的n条线
        g.setColor(Color.red);
        for(int i=0;i<5;i++){   
        g.drawLine(randomNume(0,w),randomNume(0,h) ,randomNume(0,w),randomNume(0,h) );
        }
        //6.在画布上写字
        //字体要求也要随机生成一个颜色
        //常用中文字体库
        String base = "\u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\u591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934\u9053\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761\u767d\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d\u679c\u600e\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148\u529b\u5b8c\u5374\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207\u661f\u5bfc\u665a\u8868\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1\u4eae\u8f7b\u8bb2\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64\u6cbb\u5317\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\u901a\u51b2\u5408\u7834\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\u7b97\u81f3\u653f\u57ce\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\u6027\u97f3\u7b54\u54e5\u9645\u65e7\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5\u9876\u6025\u6797\u505c\u606f\u53e5\u533a\u8863\u822c\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6";
        for(int i=0;i<5;i++){
        g.setColor(new Color(randomNume(0,255),randomNume(0,255),randomNume(0,255)));
        g.setFont(new Font("黑体",Font.BOLD,20));
        int r=randomNume(-45,45);
        g.rotate(1.0*r/180*Math.PI,xpyl+(30*i),ypyl);
        g.drawString((base.charAt(randomNume(0,base.length()-1)))+"",xpyl+(30*i),ypyl);
        g.rotate(1.0*-                                                                                                               r/180*Math.PI,xpyl+(30*i),ypyl);
        }
        ImageIO.write(image, "jpg",response.getOutputStream());
        
    }

        private Random rd=new Random();
        private int randomNume(int bigen,int end){
            return rd.nextInt(end-bigen)+bigen;
            
        }


    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

response中实现的一些功能

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