Web服务器接收到客户端的http请求，会针对每一次请求，分别创建一个用于代表请求的request对象、和代表响应的response对象。request和response对象既然代表请求和响应，那么我们要获取客户机提交过来的数据，只需要找request对象，就行了。要向客户机输出数据，只需要找response对象就行了。HttpServletRequest封装客户端相关信息，服务器Servlet程序可以通过request对象操作客户端信息HttpServletResponse封装服务器向客户端发送响应数据信息，Servlet程序通过response对象向客户端发送响应
response1.response常用APIsetStatus：设置响应行当中的状态码setHeader：设置响应头信息getOutputStream：获得字节流 --- 输出响应体内容getWriter：获得字符流 --- 输出响应体内容2.HttpServletResponse继承ServletResponse接口，ServletResponse并没有提供与HTTP协议相关API，HttpServletResponse添加了与协议相关APIJavaEE API 中并没有提供HttpServletResponse实现类---实现类由tomcat服务器提供的3.常用状态码：200 302 304 404 500200 请求处理成功302 客户端重定向304 客户端访问资源没有被修改，客户端访问本地缓存404 访问资源不存在500 服务器内部出错4.案例一：通过302+Location头信息实现页面重定向
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class ResponseServlet1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//302客户端重定向 --- 结合Location头信息一起使用
response.setStatus(302);
//通知浏览器定向到哪个页面
response.setHeader("Location", "/Response/welcome.html");
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
response.setStatus(302);response.setHeader("Location", "/Response/welcome.html");&& &//由客户端定向到服务器，必须添加工程虚拟目录
案例二：登陆重定向在response API中提供sendRedirect() --- 完成302+Location重定向效果例如：response.sendRedirect("/day06/welcome.html");eg：
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class ResponseServlet2 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
if("admin".equals(username) && "admin".equals(password)){
response.setStatus(302);
response.setHeader("Location", "/Response/welcome.html");
//使用response.sendRedirect完成重定向
response.sendRedirect("/Response/welcome.html");
response.setStatus(302);
response.setHeader("Location", "/Response/login.html");
response.sendRedirect("/Response/login.html");
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
案例三：自动刷新网页*登陆成功，5秒后自动跳转XX页面原理：通过refresh头信息格式 --- refresh:时间;url=跳转路径例如：refresh:3;url=& --- 3秒后自动跳转网站
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class ResponseServlet3 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setHeader("refresh", "3;url=");
response.setContentType("text/charset=utf-8");
response.getWriter().println("3秒后跳转到百度");
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
在HTML页面中存在一类非常特殊标签&meta&,&meta&起到设置头信息作用&meta content="3;url=" http-equiv="refresh"&& ---- 完成自动跳转案例四：通过response头信息设置浏览器禁止缓存原理：和禁止缓存相关头信息（三个）Cache-Control:no-cacheExpires:-1Pragma:no-cacheeg:
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class ResponseServlet4 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Pragma", "no-cache");
response.setDateHeader("expires", -1);
response.getWriter().println("Hello");
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
中文乱码问题通过response生成客户端响应体，通过字节流和字符流两种输出方式*哪些情况用字节流？哪些情况用字符流？拷贝文件 --- 字节流分析文件内容 --- 字符流& （中文操作 字符流）案例五：输出中文信息
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class ResponseServlet5 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//需要通知浏览器查看编码
response.setContentType("text/charset=utf-8");
//设置响应编码与浏览器查看编码
PrintWriter out = response.getWriter();
out.println("我很好！");
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
setCharacterEncoding 和 setContentType区别？setCharacterEncoding 设置响应内容编码，无法设置浏览器查看编码setContentType设置响应内容编码，同时通知浏览器查看编码*在响应头信息中 Content-Type:text/charset=utf-8结论：setContentType具备setCharacterEncoding编码功能，现实开发中，只需要使用setContentType就可以了注意：1）getOutputStream和getWriter不能同时使用2）必须在getOutputStream喝getWriter之前设置响应编码3）getOutputStream和getWriter输出内容是HTTP响应体4）getOutputStream和getWriter存在缓冲区，在service方法结束时，自动关闭流，flush缓冲区内容案例六：文件下载第一种：通过超链接完成文件下载*如果浏览器可以识别该文件格式，直接打开，只有链接文件浏览器不识别文件格式，才会实现下载第二种：通过Servlet程序实现下载原理：通过Servlet读取目标程序，将资源返回客户端通过程序下载文件，设置两个头信息Content-Type Content-Disposition
response.setContentType(getServletContext().getMimeType(filename));&&&& ----设置文件类型response.setHeader("Content-Disposition","filename="+filename); ----设置文件以附件形式下载（对于浏览器识别格式文件）eg:
&!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"&
&title&download.html&/title&
&h1&通过超链接实现文件下载&/h1&
&a href="/Response/download/xpp3.zip"&zip压缩包下载&/a&
&a href="/Response/download/mm.jpg"&jpg图片下载&/a&
&!-- 通过?在url地址里拼接参数 get方式提交 --&
&h1&通过程序实现下载&/h1&
&a href="/Response/response6?filename=xpp3.zip"&zip压缩包下载&/a&
&a href="/Response/response6?filename=mm.jpg"&jpg图片下载&/a&
package cn.lsl.
import java.io.FileInputS
import java.io.IOE
import java.io.InputS
import java.io.OutputS
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class ResponseServlet6 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//获得文件名
String filename = request.getParameter("filename");
response.setContentType(getServletContext().getMimeType(filename));
//设置MIME类型
response.setHeader("Content-Disposition", "filename=" + filename);
//绝对磁盘路径
String fullFilename = getServletContext().getRealPath("/download/" + filename);
InputStream in = new FileInputStream(fullFilename);
OutputStream out = response.getOutputStream();
while((b=in.read())!=-1){
out.write(b);
in.close();
out.close();
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
案例七：验证码输出案例Java图形API生成验证码图片为什么需要验证码？防止有人通过程序恶意攻击网站eg：
package cn.lsl.
import java.awt.C
import java.awt.F
import java.awt.G
import java.awt.Graphics2D;
import java.awt.image.BufferedI
import java.io.IOE
import java.util.R
import javax.imageio.ImageIO;
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class ResponseServlet7 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
int width = 120;
int height = 30;
//创建一张内存中缓冲图片
BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
Graphics graphics = bufferedImage.getGraphics();
//通过graphics对象绘制图片
graphics.setColor(Color.YELLOW);
graphics.fillRect(0, 0, width, height);
graphics.setColor(Color.BLUE);
graphics.drawRect(0, 0, width-1, height-1);
//写验证内容
Graphics2D graphics2d = (Graphics2D)bufferedImage.getGraphics();
graphics2d.setColor(Color.RED);
graphics2d.setFont(new Font("宋体",Font.BOLD,18));
//String content = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
String content = "\u\u4e86\u662f\ud\u5728\u4eba\u4eec\u\u4ed6\u8fd9\u4e0a" +
"\ua\u\u5927\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\ub" +
"\u770b\u\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\u591a\u6ca1\u4e3a" +
"\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u\u60f3\u751f\u540c\ud\u5341" +
"\u4ece\u81ea\ud\u\u5b83\u540e\u\u5f88\u50cf\u89c1\u4e24\u" +
"\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\u6c11" +
"\u5019\u7ecf\u53d1\u5de5\ub\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8" +
"\u624b\u77e5\uc\u5fd7\u70b9\u5fc3\uc\u95ee\u4f46\u8eab\u65b9\u5b9e\ua" +
"\u53eb\u5f53\u4f4f\u542c\u\uf\ud\u56db\u5df2\uc\u4e4b\u6700" +
"\u\u60c5\u8def\ub\ud\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1" +
"\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\ub\u\u8fd0\u518d\u679c\u600e" +
"\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u\ub\u90e8\u95e8\u65e0\u5f80" +
"\ub\u65b0\u5e26\u961f\ub\u5b8c\u\u4ee3\ua\u66f4\u4e5d\u60a8" +
"\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66" +
"\u91cd\u4fbf\uc\u54ea\ua\u\u793e\u4f3c\u58eb\u\u77f3\u6ee1" +
"\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76\ud\u672c\u601d\u89e3\u7acb\u6cb3\ub" +
"\u96be\u65e9\u8bba\u\u\u76f8\u7814\u4eca\u\u\u5e94\u5173" +
"\u4fe1\u89c9\u6b65\u53cd\u\u5c06\ue\u4e89\u\u5e08\u7ed3\u" +
"\u8c01\ua\u5b57\u52a0\u811a\u7d27\u\u4e60\u\u\u534a\u706b" +
"\u6cd5\u9898\u5efa\u8d76\u4f4d\u\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b" +
"\u79bb\u\u\ub\u\u521a\u4e14\u\uf\u5bfc" +
"\u665a\uf\u\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\u\u529e\u53f2\u\u8f6c\u753b\u\u6b64\u6cbb\u" +
"\u670d\u96e8\u7a7f\u\u9a8c\u4f20\u4e1a\u83dc\u722c\u\u5f62\u91cf\u54b1\u89c2" +
"\u82e6\u4f53\u4f17\u901a\u51b2\u\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u" +
"\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u\u81f3\u653f\u57ce\u52b3\u843d\u94b1" +
"\u\u5f1f\u80dc\u6559\u70ed\u5c55\uc\u7c7b\u6e10\u5f3a\u\u547c\u6027" +
"\u97f3\u7b54\u54e5\u\u795e\u5ea7\u7ae0\u5e2e\u\u7cfb\u4ee4\u8df3\u975e\u4f55" +
"\u725b\u53d6\u\u\u5ffd\u79cd\u88c5\u\uc\u606f\u53e5\u533a" +
"\uc\u62a5\u53f6\u538b\u\u80cc\u7ec6";
//内容四个字 -- 随机从content中抽取四个字
Random random = new Random();
for(int i=0; i&4; i++){
//为字生成旋转角度 -30 -- 30
double jiaodu = random.nextInt(60) - 30;
//将旋转角度换算弧度
double theta = jiaodu/180*Math.PI;
System.out.println(theta);
int index = random.nextInt(content.length());
char letter = content.charAt(index);
graphics2d.rotate(theta, x, y);
graphics2d.drawString(letter+"", x, y);
//将角度还原
graphics2d.rotate(-theta, x, y);
//绘制随机干扰线
graphics.setColor(Color.LIGHT_GRAY);
for(int i=0; i&10; i++){
x1 = random.nextInt(width);
x2 = random.nextInt(width);
y1 = random.nextInt(height);
y2 = random.nextInt(height);
//根据两点
graphics.drawLine(x1, y1, x2, y2);
//内存中资源释放
graphics.dispose();
//将图片输出到浏览器 ImageIO
//将内存的图片通过浏览器输出流写成jpg格式图片
ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
分析：验证码旋转效果 rotate(double theta, double x, double y)& ----- 参数 theta 旋转弧度 2PI 弧度 = 360 角度 -30 ---- 30 角度
RequestHttpServletRequest相比ServletRequest添加与协议相关的APIHttpServletRequest对象代表客户端的请求，当客户端通过HTTP协议访问服务器时，HTTP请求中的所有信息都封装在这个对象中，可通过这个对象的方法，获取客户这些信息。HttpServletRequest分为四个部分1.获取客户机信息1）几个方法：getRequestURL方法返回客户端发出请求完整URLgetRequestURI方法返回请求行中的资源名部分getQueryString方法返回请求行中的参数部分getRemoteAddr方法返回发出请求的客户机的IP地址getMethod得到客户机请求方式getContextPath获得工程虚拟目录名称
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class RequestServlet1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("url:" + request.getRequestURL());
System.out.println("uri:" + request.getRequestURI());
//通过getQueryString可以获得get方式提交查询串url中？后面部分
System.out.println("querystring:" + request.getQueryString());
//获得客户端ip
System.out.println("ip:" + request.getRemoteAddr());
//通过getContextPath获得工程虚拟目录名称
System.out.println(request.getContextPath());
//通过getMethod获取请求方式
System.out.println("请求方式:" + request.getMethod());
//获得当前访问资源路径
--- /request1
System.out.println("当前访问资源路径:" + request.getRequestURI().substring(request.getContextPath().length()));
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
URI和URL区别url:http://localhost:8080/Request/request1& （完整）uri:/Request/request1& （部分）URI包含URL的http://localhost:8080/Request/request1 是一个URL，同时也是URI./hello& /day06/request1 都是URI，不是URL2.获取请求头信息getHeader获得头信息的值，转换一个字符串getHeaders获得头信息值，返回EnumerationgetHeaderNames获得所有头信息名称，返回Enumerationeg:
package cn.lsl.
import java.io.IOE
import java.util.E
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class RequestServlet2 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String value = request.getHeader("Accept-Encoding");
System.out.println(value);
System.out.println("--------------");
Enumeration&String& enumeration = request.getHeaderNames();
while(enumeration.hasMoreElements()){
String name = enumeration.nextElement();
System.out.println(name + ":" + request.getHeader(name));
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
案例：编写防盗链程序，存在合法referer不是盗链，否则控制目标资源无法访问！
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class RequestServlet3 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String referer = request.getHeader("referer");
response.setContentType("text/charset=utf-8");
if(referer == null || !referer.startsWith("http://localhost")){
response.getWriter().println("是盗链");
response.getWriter().println("不是盗链");
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
3.获取请求参数什么是请求参数？用户用过请求提交服务器一些数据四个常用APIgetParametergetParameterValuesgetParameterNamesgetParameterMapeg:
&!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"&
&title&request.html&/title&
&h1&分别以get和post方式提交数据&/h1&
&h1&第一种 通过超链接提交数据 以？方式&/h1&
&a href="/Request/request4?name=zhangsan&&city=beijing""&超链接提交数据&/a&
&h1&第二种 通过form的post方式提交数据&/h1&
&form action="/Request/request4" method="post"&
请输入姓名&input type="text" name="name" /&&br/&
请输入城市&input type="text" name="city" /&&br/&
&input type="submit" value="提交" /&
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class RequestServlet4 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//通过getParameter获得请求数据
String name = request.getParameter("name");
System.out.println(name);
String city = request.getParameter("city");
System.out.println(city);
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
乱码问题post --- request.setCharacterEncoding("客户端编码集");get乱码手动解决：username = URLEncoder.encode(username, "ISO-8859-1");// 用ISO编码username = URLDecoder.decode(username, "utf-8"); // 用utf-8解码简化上面写法 ： username = new String(username.getBytes("ISO-8859-1"), "utf-8")get乱码 配置tomcat默认解码字符集在tomcat/conf/server.xml Connector中 添加一个属性 URIEncoding="utf-8"结论：开发时，尽量不要修改tomcat默认解码集，提交请求尽量使用post，如果非要使用get，手动编码问题：http://localhost/day06/servlet?username=zhangsan+lisi在服务器端 通过 request.getParameter("username") 结果是 ？？？ ----- zhangsan lisi数据获取和乱码解决的案例：
&!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"&
&meta http-equiv="Content-Type" content="text/ charset=UTF-8"&
&title&Insert title here&/title&
&!-- 最复杂form表单 --&
&!-- 用户注册 --&
&form action="/Request/request5" method="post"&
&!-- 文本输入框 --&
&td&用户名&/td&
&td&&input type="text" name="username"/&&/td&
&!-- 密码框 --&
&td&密码&/td&
&td&&input type="password" name="password" /&&/td&
&!-- 单选按钮 --&
&td&性别&/td&
&input type="radio" name="gender" value="male" /& 男
&input type="radio" name="gender" value="female" /&女
&!-- 复选框
&td&爱好&/td&
&input type="checkbox" name="hobby" value="sport" /& 体育
&input type="checkbox" name="hobby" value="music" /& 音乐
&input type="checkbox" name="hobby" value="game" /& 游戏
&!-- 下拉框 --&
&td&城市&/td&
&select name="city"&
&option value="beijing"&北京&/option&
&option value="shanghai"&上海&/option&
&option value="shenzhen"&深圳&/option&
&!-- 多行文本框 --&
&td&个人简介&/td&
&textarea rows="5" cols="60" name="introduce"&&/textarea&
&td colspan="2"&&input type="submit" value="注册"/&&/td&
package cn.lsl.
import java.io.IOE
import java.net.URLD
import java.net.URLE
import java.util.A
import java.util.E
import java.util.M
import java.util.S
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class RequestServlet5 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//解决post乱码
request.setCharacterEncoding("utf-8");
String username = request.getParameter("username");
System.out.println(username);
解决get乱码 --- 使用手动编码
username = URLEncoder.encode(username, "ISO-8859-1");
//用ISO编码
username = URLDecoder.decode(username, "utf-8");
//用utf-8解码
//以下一句等效于上面两句
username = new String(username.getBytes("ISO-8859-1"), "UTF-8");
System.out.println(username);
String[] hobbies = request.getParameterValues("hobby");
System.out.println(Arrays.toString(hobbies));
//打印所有请求提交参数
//方式一：先获得所有参数name，然后通过name获得value
Enumeration&String& names = request.getParameterNames();
while(names.hasMoreElements()){
String name = names.nextElement();
//获得每一参数名称
System.out.println(name + Arrays.toString(request.getParameterValues(name)));
System.out.println("--------------");
Map&String, String[]& paramterMap = request.getParameterMap();
Set&String& keys = paramterMap.keySet();
for(String key : keys){
System.out.println(key + ":" + Arrays.toString(paramterMap.get(key)));
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
4.利用请求域传递对象HttpServletRequest和ServletContext类似，都是数据域对象，以Map方式保存数据区分：ServletContext对象：服务器启动对象创建，服务器停止对象销毁ServletRequest对象：当产生一次请求时创建，当响应结束后，对象销毁eg:
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.RequestD
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class AServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//通过request对象传递
//向request域对象保存一个属性
request.setAttribute("name", "lsl");
//传递数据给BServlet必须使用请求转发
RequestDispatcher dispatcher = request.getRequestDispatcher("/b");
dispatcher.forward(request, response);
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class BServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println(request.getAttribute("name"));
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
注意事项：1）在使用forward之前，不能将响应内容传输到客户端情况一：response输出流输出流执行flush，导致内容不能输出情况二：同一个Servlet不能连续使用forward和redirect2）在执行forward和redirect时，清除之前写入响应流数据3）ServletContext进行转发路径必须以/开始，request进行转发路径可以使用相对路径转发和重定向区别：1、转发一次请求、一次响应，重定向 两次请求 两次响应2、转发只能跳转站内程序，重定向定向任何站点 3、转发 URL地址不变 ，重定向URL地址改变 4、转发 对客户端不可见，重定向对客户端可见 5、转发共享同一个Request中数据，重定向两次请求，不同Request对象，不能共享Request数据 * request.setAttribute 必须和 request.getRequestDispatcher().forward 一起使用RequestDispatcher 的 include 方法 用来做页面布局 ------ &%@include%& &jsp:include& 将页面公共部分抽取出来，通过include 引用到页面中 ---- 更加方便维护
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class MainServlet1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.getRequestDispatcher("/logo.html").include(request, response);
response.getOutputStream().println("&h1&A&/h1&");
request.getRequestDispatcher("/footer.html").include(request, response);
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
package cn.lsl.
import java.io.IOE
import java.io.PrintW
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
public class MainServlet2 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.getRequestDispatcher("/logo.html").include(request, response);
response.getOutputStream().println("&h1&B&/h1&");
request.getRequestDispatcher("/footer.html").include(request, response);
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
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