J2EE进阶之Response 和Request 十

本是古典何须时尚 2024-02-17 23:46 66阅读 0赞

## **Servlet之Request和Response** ##

### HttpServletRequest和HttpServletResponse概述 ###

这两个对象的实例由Web服务器创建的。
    客户端发送请求，服务器接收请求，创建两个对象，一个有值，一个为空。服务端接收数据和设置数据。

![kIhvE6V.jpg][]

### HttpServletResponse ###

#### 以字节流的形式向客户端输出中文 ####

1 package com.wsj;
      2 
      3 import java.io.IOException;
      4 
      5 import javax.servlet.ServletException;
      6 import javax.servlet.ServletOutputStream;
      7 import javax.servlet.http.HttpServlet;
      8 import javax.servlet.http.HttpServletRequest;
      9 import javax.servlet.http.HttpServletResponse;
     10 /**
     11  * 以字节流的形式向客户端输出中文
     12  * @author Angus
     13  */
     14 public class ResponseDemo1 extends HttpServlet {
     15 
     16     public void doGet(HttpServletRequest request, HttpServletResponse response)
     17             throws ServletException, IOException {
     18         test5(response);
     19     }
     20     
     21     //结论：test3、4、5写法形式不一样，但作用都是告诉客户端响应正文的MIME类型及编码
     22     
     23     //字节流：用UTF-8编码输出中文。解决乱码方式一:推荐
     24     private void test5(HttpServletResponse response) throws IOException {
     25         String data = "哈哈哈哈5";
     26         ServletOutputStream sos = response.getOutputStream();
     27         byte b[] = data.getBytes("UTF-8");
     28         response.setContentType("text/html;charset=UTF-8");
     29         sos.write(b);
     30     }
     31     //字节流：用UTF-8编码输出中文。解决乱码方式一:推荐
     32     private void test4(HttpServletResponse response) throws IOException {
     33         String data = "哈哈哈哈4";
     34         ServletOutputStream sos = response.getOutputStream();
     35         byte b[] = data.getBytes("UTF-8");
     36         response.setHeader("Content-Type", "text/html;charset=UTF-8");//设置响应消息头
     37         sos.write(b);
     38     }
     39     //字节流：用UTF-8编码输出中文。解决乱码方式一:不推荐
     40     private void test3(HttpServletResponse response) throws IOException {
     41         String data = "哈哈哈哈3";
     42         ServletOutputStream sos = response.getOutputStream();
     43         byte b[] = data.getBytes("UTF-8");
     44         sos.write("<meta http-equiv='Content-Type' content='text/html;charset=UTF-8'>".getBytes());
     45         sos.write(b);
     46     }
     47     //字节流：用UTF-8编码输出中文。结论：默认情况下，有乱码。可以通过调整浏览器的编码为UTF-8显示正常了。不靠谱
     48     private void test2(HttpServletResponse response) throws IOException {
     49         String data = "哈哈哈哈2";
     50         ServletOutputStream sos = response.getOutputStream();
     51         byte b[] = data.getBytes("UTF-8");
     52         sos.write(b);
     53     }
     54     //字节流：用本地默认编码输出中文。结论：没有乱码
     55     private void test1(HttpServletResponse response) throws IOException {
     56         String data = "哈哈哈哈1";
     57         ServletOutputStream sos = response.getOutputStream();
     58         byte b[] = data.getBytes();//字符--->字节：查码表  getBytes()查本地默认的。GBK
     59         sos.write(b);
     60     }
     61 
     62     public void doPost(HttpServletRequest request, HttpServletResponse response)
     63             throws ServletException, IOException {
     64         doGet(request, response);
     65     }
     66 
     67 }

#### 用字符流输出中文数据 ####

1 package com.wsj;
      2 
      3 import java.io.IOException;
      4 import java.io.PrintWriter;
      5 
      6 import javax.servlet.ServletException;
      7 import javax.servlet.http.HttpServlet;
      8 import javax.servlet.http.HttpServletRequest;
      9 import javax.servlet.http.HttpServletResponse;
     10 /**
     11  * 用字符流输出中文数据
     12  * @author Angus
     13  *
     14  */
     15 public class ResponseDemo2 extends HttpServlet {
     16 
     17     public void doGet(HttpServletRequest request, HttpServletResponse response)
     18             throws ServletException, IOException {
     19         test3(response);
     20     }
     21     //字符流：使用UTF-8输出。
     22     private void test3(HttpServletResponse response) throws IOException {
     23 //      response.setCharacterEncoding("UTF-8");//更改输出字符流使用的编码为UTF-8
     24         response.setContentType("text/html;charset=UTF-8");//通知客户端用UTF-8进行显示，还能更改字符流使用的编码
     25         String data = "哈哈哈哈3";
     26         PrintWriter out = response.getWriter();
     27         out.write(data);
     28     }
     29     //字符流：使用UTF-8输出。推荐的
     30     private void test2(HttpServletResponse response) throws IOException {
     31         response.setCharacterEncoding("UTF-8");//更改输出字符流使用的编码为UTF-8
     32         response.setContentType("text/html;charset=UTF-8");//通知客户端用UTF-8进行显示
     33         String data = "哈哈哈哈2";
     34         PrintWriter out = response.getWriter();
     35         out.write(data);
     36     }
     37 
     38     //字符流：默认编码ISO-8859-1输出。结论：有乱码
     39     private void test1(HttpServletResponse response) throws IOException {
     40         String data = "哈哈哈哈1";
     41         PrintWriter out = response.getWriter();
     42         out.write(data);//默认用的ISO-8859-1，乱码必定存在
     43     }
     44 
     45     public void doPost(HttpServletRequest request, HttpServletResponse response)
     46             throws ServletException, IOException {
     47         doGet(request, response);
     48     }
     49 
     50 }

#### 中文名称的文件下载 ####

1 package com.wsj;
      2 
      3 import java.io.File;
      4 import java.io.FileInputStream;
      5 import java.io.IOException;
      6 import java.io.InputStream;
      7 import java.io.OutputStream;
      8 import java.net.URLEncoder;
      9 
     10 import javax.servlet.ServletException;
     11 import javax.servlet.ServletOutputStream;
     12 import javax.servlet.http.HttpServlet;
     13 import javax.servlet.http.HttpServletRequest;
     14 import javax.servlet.http.HttpServletResponse;
     15 /**
     16  * 中文名称的文件的下载
     17  * @author Angus
     18  *  File.separator  相当于斜线/ 这样可以跨平台运行使用
     19  */
     20 public class ResponseDemo4 extends HttpServlet {
     21 
     22     public void doGet(HttpServletRequest request, HttpServletResponse response)
     23             throws ServletException, IOException {
     24         //使用相对路径
     25         String file = getServletContext().getRealPath("/WEB-INF/哈哈.png");
     26         
     27         InputStream is = new FileInputStream(file);
     28         
     29         //截取文件名
     30         //File.separator  相当于斜线/ 这样可以跨平台运行使用
     31         String filename = file.substring(file.lastIndexOf(File.separator)+1);
     32         response.setHeader("Content-Disposition", "attachment;filename = "+URLEncoder.encode(filename, "UTF-8"));//中文文件下载时要进行URL编码
     33         
     34         OutputStream out = response.getOutputStream();
     35         
     36         int len = -1;
     37         byte b[] = new byte[1024];
     38         while((len = is.read()) != -1){
     39             out.write(b);
     40         }
     41         is.close();
     42         out.close();
     43         
     44     }
     45 
     46     public void doPost(HttpServletRequest request, HttpServletResponse response)
     47             throws ServletException, IOException {
     48         doGet(request, response);
     49     }
     50 
     51 }

#### 获取随机验证码： ####

1 package com.wsj;
      2 
      3 import java.awt.Color;
      4 import java.awt.Font;
      5 import java.awt.Graphics;
      6 import java.awt.image.BufferedImage;
      7 import java.io.IOException;
      8 import java.util.Random;
      9 
     10 import javax.imageio.ImageIO;
     11 import javax.servlet.ServletException;
     12 import javax.servlet.http.HttpServlet;
     13 import javax.servlet.http.HttpServletRequest;
     14 import javax.servlet.http.HttpServletResponse;
     15 
     16 import cn.dsna.util.images.ValidateCode;
     17 /**
     18  * 输出随机验证码图片
     19  * @author Angus
     20  *
     21  */
     22 public class ResponseDemo5 extends HttpServlet {
     23 
     24     public void doGet(HttpServletRequest request, HttpServletResponse response)
     25             throws ServletException, IOException {
     26         test2(response);
     27     }
     28     private void test2(HttpServletResponse response) throws IOException {
     29         
     30         //不要缓存
     31         response.setHeader("Expires", "-1");
     32         response.setHeader("Cache-Control", "no-cache");
     33         response.setHeader("Pragma", "no-cache");
     34         
     35         //参数：宽度 高度 验证码个数 干扰线数量  
     36         //用第三方jar包实现  ValidateCode.jar搜索下载即可
     37         ValidateCode vc = new ValidateCode(120, 25, 4, 100);
     38         vc.write(response.getOutputStream());
     39     }
     40     //自己画CAPTCHA图像
     41     private void test1(HttpServletResponse response) throws IOException {
     42         //创建一副内存图像：BufferedImage
     43         BufferedImage image = new BufferedImage(120, 20, BufferedImage.TYPE_INT_RGB);
     44         //得到画笔：画
     45         Graphics g = image.getGraphics();
     46             //边线
     47             g.setColor(Color.BLUE);
     48             g.drawRect(0, 0, 120, 20);
     49             //填充底色
     50             g.setColor(Color.GRAY);
     51             g.fillRect(1, 1, 120-2, 20-2);
     52             Random r = new Random();
     53             //画验证码
     54             g.setColor(Color.RED);
     55             g.setFont(new Font("宋体", Font.BOLD|Font.ITALIC,20));
     56             int x = 18;
     57             for(int i=0;i<4;i++){
     58                 g.drawString(r.nextInt(10)+"", x, 18);
     59                 x+=20;
     60             }
     61             //画干扰线
     62             g.setColor(Color.YELLOW);
     63             
     64             for(int i=0;i<10;i++){
     65                 g.drawLine(r.nextInt(120), r.nextInt(20),r.nextInt(120), r.nextInt(20));
     66             }
     67         //用response的字节流输出图像
     68         ImageIO.write(image, "jpg", response.getOutputStream());
     69     }
     70 
     71     public void doPost(HttpServletRequest request, HttpServletResponse response)
     72             throws ServletException, IOException {
     73         doGet(request, response);
     74     }
     75 
     76 }

效果图：

![7oqyasT.jpg][]

##### 控制客户端定时刷新 #####

1 package com.wsj;
      2 
      3 import java.io.IOException;
      4 import java.util.Random;
      5 
      6 import javax.servlet.ServletException;
      7 import javax.servlet.http.HttpServlet;
      8 import javax.servlet.http.HttpServletRequest;
      9 import javax.servlet.http.HttpServletResponse;
     10 /**
     11  * 控制客户端定时刷新
     12  * @author Angus
     13  *
     14  */
     15 public class ResponseDemo6 extends HttpServlet {
     16 
     17     public void doGet(HttpServletRequest request, HttpServletResponse response)
     18             throws ServletException, IOException {
     19         test2(response);
     20     }
     21     //刷新到别处
     22     private void test2(HttpServletResponse response) throws IOException {
     23         response.setContentType("text/html;charset=UTF-8");
     24         //设置响应消息头
     25         response.setHeader("Refresh", "2;URL=http://www.baidu.com");
     26         response.getWriter().write("登录成功！2秒后自动跳转到主页");
     27     }
     28     private void test1(HttpServletResponse response) throws IOException {
     29         Random r =  new Random();
     30         //设置响应消息头
     31         response.setIntHeader("Refresh", 1);//刷新自己
     32         response.getWriter().write(r.nextInt()+"");
     33     }
     34 
     35     public void doPost(HttpServletRequest request, HttpServletResponse response)
     36             throws ServletException, IOException {
     37         doGet(request, response);
     38     }
     39 
     40 }

##### 控制资源缓存时间 #####

1 import java.io.IOException;
      2 
      3 import javax.servlet.ServletException;
      4 import javax.servlet.http.HttpServlet;
      5 import javax.servlet.http.HttpServletRequest;
      6 import javax.servlet.http.HttpServletResponse;
      7 /**
      8  * 控制资源的缓存时间
      9  * 这样就不会每次都是刷新服务器，先获取缓存数据
     10  * @author Angus
     11  *
     12  */
     13 public class ResponseDemo7 extends HttpServlet {
     14 
     15     public void doGet(HttpServletRequest request, HttpServletResponse response)
     16             throws ServletException, IOException {
     17         response.setDateHeader("Expires", System.currentTimeMillis()+20000);//取值是一个毫秒值，该值是一个相对时间
     18         response.getWriter().write("hello");
     19     }
     20 
     21     public void doPost(HttpServletRequest request, HttpServletResponse response)
     22             throws ServletException, IOException {
     23         doGet(request, response);
     24     }
     25 
     26 }

##### 重定向 #####

1 import java.io.IOException;
      2 
      3 import javax.servlet.ServletException;
      4 import javax.servlet.http.HttpServlet;
      5 import javax.servlet.http.HttpServletRequest;
      6 import javax.servlet.http.HttpServletResponse;
      7 /**
      8  * 实现请求重定向:目标地址可以任意
      9  * @author Angus
     10  *
     11  */
     12 public class ResponseDemo8 extends HttpServlet {
     13 
     14     public void doGet(HttpServletRequest request, HttpServletResponse response)
     15             throws ServletException, IOException {
     16         response.sendRedirect("http://www.baidu.cn");
     17     }
     18 
     19     private void test1(HttpServletResponse response) {
     20         response.setStatus(302);
     21         response.setHeader("Location", "http://www.baidu.com");
     22     }
     23 
     24     public void doPost(HttpServletRequest request, HttpServletResponse response)
     25             throws ServletException, IOException {
     26         doGet(request, response);
     27     }
     28 
     29 }

#### response细节 ####

1：getOutputStream和getWriter方法分别用于得到输出二进制数据、输出文本数据的ServletOuputStream、Printwriter对象。

2：getOutputStream和getWriter这两个方法互相排斥，调用了其中的任何一个方法后，就不能再调用另一方法。 会抛异常。

3;Servlet程序向ServletOutputStream或PrintWriter对象中写入的数据将被Servlet引擎从response里面获取，Servlet引擎将这些数据当作响应消息的正文，然后再与响应状态行和各响应头组合后输出到客户端。

4:Serlvet的service方法结束后，Servlet引擎将检查getWriter或getOutputStream方法返回的输出流对象是否已经调用过close方法，如果没有，Servlet引擎将调用close方法关闭该输出流对象

### HttpServletRequest ###

HttpServletRequest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请求头中的所有信息都封装在这个对象中，开发人员通过这个对象的方法，可以获得客户这些信息

#### 方法1 获得客户机信息 ####

1 package wsj;
      2 
      3 import java.io.IOException;
      4 import javax.servlet.ServletException;
      5 import javax.servlet.annotation.WebServlet;
      6 import javax.servlet.http.HttpServlet;
      7 import javax.servlet.http.HttpServletRequest;
      8 import javax.servlet.http.HttpServletResponse;
      9 
     10 /**
     11  * Request
     12  * @author Angus
     13  *  获得客户机信息
     14     getRequestURL方法返回客户端发出请求时的完整URL。
     15     getRequestURI方法返回请求行中的资源名部分。
     16     getQueryString 方法返回请求行中的参数部分。
     17     getRemoteAddr方法返回发出请求的客户机的IP地址
     18     getRemoteHost方法返回发出请求的客户机的完整主机名
     19     getRemotePort方法返回客户机所使用的网络端口号
     20     getLocalAddr方法返回WEB服务器的IP地址。
     21     getLocalName方法返回WEB服务器的主机名
     22     getMethod得到客户机请求方式
     23  */
     24 @WebServlet("/demo1")
     25 public class RequestDemo1 extends HttpServlet {
     26 
     27     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
     28         System.out.println(request.getClass().getName());
     29         System.out.println("getRequestURL()"+request.getRequestURL().toString());
     30         System.out.println("getRequestURI"+request.getRequestURI());
     31         System.out.println("getQueryString"+request.getQueryString());
     32         System.out.println("getRemoteAddr()"+request.getRemoteAddr());
     33         System.out.println("getRemoteHost()"+request.getRemoteHost());
     34         System.out.println("getRemotePort()"+request.getRemotePort());
     35         System.out.println("getLocalAddr()"+request.getLocalAddr());
     36         System.out.println("getLocalName()"+request.getLocalName());
     37         System.out.println("getMethod()"+request.getMethod());
     38     }
     39 
     40 
     41     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
     42         doGet(request, response);
     43     }
     44 
     45 }

##### 运行结果： #####

![20DGmlR.jpg][]

#### 方法2获取请求头信息 ####

getHead(name)方法 
    getHeaders(String name)方法 
    getHeaderNames方法

#### \# ####

1 
      2 
      3 import java.io.IOException;
      4 import java.util.Enumeration;
      5 
      6 import javax.servlet.ServletException;
      7 import javax.servlet.http.HttpServlet;
      8 import javax.servlet.http.HttpServletRequest;
      9 import javax.servlet.http.HttpServletResponse;
     10 /**
     11  * 获取请求消息头
     12  * @author Angus
     13  *
     14  */
     15 public class RequestDemo2 extends HttpServlet {
     16 
     17     public void doGet(HttpServletRequest request, HttpServletResponse response)
     18             throws ServletException, IOException {
     19         test3(request, response);
     20     }
     21     //获取所有头名称
     22     private void test3(HttpServletRequest request, HttpServletResponse response)
     23             throws ServletException, IOException {
     24         Enumeration<String> e = request.getHeaderNames();//所有头名称
     25         while(e.hasMoreElements()){
     26             String headerName = e.nextElement();
     27             String headerValue = request.getHeader(headerName);
     28             System.out.println(headerName+":"+headerValue);
     29         }
     30     }
     31     //获取重名头
     32     private void test2(HttpServletRequest request, HttpServletResponse response)
     33             throws ServletException, IOException {
     34         Enumeration<String> e = request.getHeaders("Accept-Encoding");//得到的是该头的所有值
     35         while(e.hasMoreElements()){
     36             System.out.println(e.nextElement());
     37         }
     38     }
     39     //获取指定头名称：单一头
     40     private void test1(HttpServletRequest request, HttpServletResponse response)
     41             throws ServletException, IOException {
     42         String userAgent = request.getHeader("User-Agent");
     43         System.out.println(userAgent);
     44     }
     45     public void doPost(HttpServletRequest request, HttpServletResponse response)
     46             throws ServletException, IOException {
     47         doGet(request, response);
     48     }
     49 
     50 }

#### 方法3获取请求参数的值 写一个提交表单提交数据和Bean来存储数据 ####

getParameter(name)方法
    getParameterValues（String name）方法
    getParameterNames方法 
    getParameterMap方法  //做框架用，非常实用
    getInputStream

#### \# ####

1 
      2 
      3 import java.beans.PropertyDescriptor;
      4 import java.io.IOException;
      5 import java.lang.reflect.Method;
      6 import java.util.Arrays;
      7 import java.util.Enumeration;
      8 import java.util.Map;
      9 
     10 import javax.servlet.ServletException;
     11 import javax.servlet.http.HttpServlet;
     12 import javax.servlet.http.HttpServletRequest;
     13 import javax.servlet.http.HttpServletResponse;
     14 
     15 import org.apache.commons.beanutils.BeanUtils;
     16 
     17 import com.itheima.domain.User;
     18 /**
     19  * 获取请求参数的值
     20  * @author Angus
     21  *
     22  */
     23 public class RequestDemo3 extends HttpServlet {
     24 
     25     public void doGet(HttpServletRequest request, HttpServletResponse response)
     26             throws ServletException, IOException {
     27         try {
     28             test7(request);
     29         } catch (Exception e) {
     30             e.printStackTrace();
     31         }
     32     }
     33     //遵守约定。最终版：借助第三方的开发jar。commons-beanutils.jar commons-logging.jar
     34     private void test7(HttpServletRequest request) throws Exception {
     35         User user = new User();
     36         System.out.println("封装前："+user);
     37         BeanUtils.populate(user, request.getParameterMap());
     38         System.out.println("封装后："+user);
     39     }
     40     private void test6(HttpServletRequest request) throws Exception {
     41         User user = new User();
     42         System.out.println("封装前："+user);
     43         //key:String类型，表单字段名username；value：String[],表单字段的值
     44         Map<String, String[]> map = request.getParameterMap();
     45         for(Map.Entry<String, String[]> me:map.entrySet()){
     46 //          System.out.println("key:"+me.getKey());
     47 //          System.out.println("value:"+Arrays.asList(me.getValue()));
     48             String fieldName = me.getKey();
     49             String fieldValues[] = me.getValue();
     50             PropertyDescriptor pd = new PropertyDescriptor(fieldName, User.class);//如果当前的fieldName是username，那么就得到了User中的getUsername和setUsername这两个方法
     51             Method method = pd.getWriteMethod();//得到setXXX方法
     52             if(fieldValues.length==1)
     53                 method.invoke(user, fieldValues);//反射main方法:Java基础加强
     54             else
     55                 method.invoke(user, (Object)fieldValues);
     56         }
     57         System.out.println("封装后："+user);
     58     }
     59     //获取所有的请求参数的名称:通用   把数据封装到JavaBean中 
     60     private void test5(HttpServletRequest request) throws Exception {
     61         Enumeration<String> e = request.getParameterNames();//请求参数的名称，约定：和JavaBean的属性一致
     62         User user = new User();
     63         System.out.println("封装前："+user);
     64         while(e.hasMoreElements()){
     65             String fieldName = e.nextElement();//username，对应着JavaBean的username属性
     66             String fieldValues[] = request.getParameterValues(fieldName);
     67             PropertyDescriptor pd = new PropertyDescriptor(fieldName, User.class);//如果当前的fieldName是username，那么就得到了User中的getUsername和setUsername这两个方法
     68             Method method = pd.getWriteMethod();//得到setXXX方法
     69             if(fieldValues.length==1)
     70                 method.invoke(user, fieldValues);//反射main方法:Java基础加强
     71             else
     72                 method.invoke(user, (Object)fieldValues);
     73         }
     74         System.out.println("封装后："+user);
     75     }
     76     //获取所有的请求参数的名称:通用   把数据封装到JavaBean中           
     77     private void test4(HttpServletRequest request) {
     78         String username = request.getParameter("username");
     79         String password[] = request.getParameterValues("password");
     80         String captcha = request.getParameter("captcha");
     81         User user = new User();
     82         user.setUsername(username);
     83         user.setPassword(password);
     84         user.setCaptcha(captcha);
     85         System.out.println(user);
     86     }
     87     //获取所有的请求参数的名称:通用   打印出来没有用
     88     private void test3(HttpServletRequest request) {
     89         Enumeration<String> e = request.getParameterNames();//请求参数的名称，对应表单中输入域的name值
     90         while(e.hasMoreElements()){
     91             String fieldName = e.nextElement();
     92             String fieldValues[] = request.getParameterValues(fieldName);
     93             System.out.println(fieldName+"="+Arrays.asList(fieldValues));
     94         }
     95     }
     96     //获取重名的请求参数的值
     97     private void test2(HttpServletRequest request) {
     98         String usernames[] = request.getParameterValues("username");
     99         String passwords[] = request.getParameterValues("password");
    100         System.out.println("username:"+Arrays.asList(usernames));
    101         System.out.println("password:"+Arrays.asList(passwords));
    102     }
    103     //获取单一的请求参数的值
    104     private void test1(HttpServletRequest request) {
    105         String username = request.getParameter("username");//为什么返回的是String？用户的所有输入都是字符串
    106         String password = request.getParameter("password");
    107         System.out.println("username:"+username);
    108         System.out.println("password:"+password);
    109     }
    110 
    111     public void doPost(HttpServletRequest request, HttpServletResponse response)
    112             throws ServletException, IOException {
    113         doGet(request, response);
    114     }
    115 
    116 }

##### 效果 #####

![M6yhcJH.jpg][]

#### RequestDispatcher接口 ####

作用：

a、实现请求转发
    b、实现动态包含

##### a、得到RequestDispatcher的实例： #####

方式一： request.getRequestDispatcher(String uri);
        方式二：ServletContext.getRequestDispatcher(String uri);uri地址必须以”/”开头，即路径必须是绝对路径。
    
    区别在于，参数uri地址的写法上。
        方式二：地址必须以/开头，/代表着当前应用。
        方式一：如果地址以/开头，/代表着当前应用；如果不以”/”，表示你用的路径是相对路径。

### \# ###

1 
      2 
      3 import java.io.IOException;
      4 
      5 import javax.servlet.RequestDispatcher;
      6 import javax.servlet.ServletException;
      7 import javax.servlet.http.HttpServlet;
      8 import javax.servlet.http.HttpServletRequest;
      9 import javax.servlet.http.HttpServletResponse;
     10 /**
     11  * 
     12  * @author Angus
     13  *
     14  */
     15 public class ForwardServlet1 extends HttpServlet {
     16 
     17     public void doGet(HttpServletRequest request, HttpServletResponse response)
     18             throws ServletException, IOException {
     19         
     20         request.setAttribute("p", "pp");
     21         
     22         RequestDispatcher rd = request.getRequestDispatcher("ForwardServlet2");
     23 //      RequestDispatcher rd = getServletContext().getRequestDispatcher("/servlet/ForwardServlet2");
     24         rd.forward(request, response);
     25     }
     26 
     27     public void doPost(HttpServletRequest request, HttpServletResponse response)
     28             throws ServletException, IOException {
     29         doGet(request, response);
     30     }
     31 
     32 }

##### b、演示包含 #####

IncludeDemo1

1 import java.io.IOException;
      2 
      3 import javax.servlet.RequestDispatcher;
      4 import javax.servlet.ServletException;
      5 import javax.servlet.http.HttpServlet;
      6 import javax.servlet.http.HttpServletRequest;
      7 import javax.servlet.http.HttpServletResponse;
      8 /**
      9  * 包含：源包含目标
     10  * @author Angus
     11  *
     12  */
     13 public class IncludeDemo1 extends HttpServlet {
     14 
     15     public void doGet(HttpServletRequest request, HttpServletResponse response)
     16             throws ServletException, IOException {
     17         response.setContentType("text/html;charset=UTF-8");
     18         response.getWriter().write("我喜欢");
     19         RequestDispatcher rd = request.getRequestDispatcher("/servlet/IncludeDemo2");
     20         rd.include(request, response);
     21     }
     22 
     23     public void doPost(HttpServletRequest request, HttpServletResponse response)
     24             throws ServletException, IOException {
     25         doGet(request, response);
     26     }
     27 
     28 }

IncludeDemo2

1 import java.io.IOException;
      2 
      3 import javax.servlet.ServletException;
      4 import javax.servlet.http.HttpServlet;
      5 import javax.servlet.http.HttpServletRequest;
      6 import javax.servlet.http.HttpServletResponse;
      7 
      8 public class IncludeDemo2 extends HttpServlet {
      9 
     10     public void doGet(HttpServletRequest request, HttpServletResponse response)
     11             throws ServletException, IOException {
     12         response.setContentType("text/html;charset=UTF-8");
     13         response.getWriter().write("凤姐");
     14     }
     15 
     16     public void doPost(HttpServletRequest request, HttpServletResponse response)
     17             throws ServletException, IOException {
     18         doGet(request, response);
     19     }
     20 
     21 }

##### 运行结果 #####

![ekVmia2.jpg][]

#### get和POST下提交中文数据的情况乱码解决 ####

1 package com.wsj;
      2 
      3 import java.io.IOException;
      4 import java.io.UnsupportedEncodingException;
      5 import java.lang.reflect.InvocationTargetException;
      6 
      7 import javax.servlet.ServletException;
      8 import javax.servlet.http.HttpServlet;
      9 import javax.servlet.http.HttpServletRequest;
     10 import javax.servlet.http.HttpServletResponse;
     11 
     12 import org.apache.commons.beanutils.BeanUtils;
     13 
     14 import com.itheima.domain.Student;
     15 /**
     16  * get和POST下提交中文数据的情况乱码解决
     17  * @author Angus
     18  *
     19  */
     20 public class RequestDemo5 extends HttpServlet {
     21 
     22     public void doGet(HttpServletRequest request, HttpServletResponse response)
     23             throws ServletException, IOException {
     24         //浏览器是UTF-8，告诉服务器用UTF-8
     25         request.setCharacterEncoding("UTF-8");//请求
     26         response.setContentType("text/html;charset=GBK");//响应
     27         String name = request.getParameter("name");
     28         response.getWriter().write(name);//有没有乱码？没有
     29     }
     30     //GET方式：E59388E59388
     31     private void test3(HttpServletRequest request)
     32             throws UnsupportedEncodingException {
     33         String name = request.getParameter("name");//默认把E59388E59388查ISO-8859-1
     34         byte b[] = name.getBytes("ISO-8859-1");//得到E59388E59388
     35         name = new String(b,"UTF-8");
     36         System.out.println(name);
     37     }
     38     //POST方式解决中文乱码问题:建议使用POST方式提交
     39     private void test2(HttpServletRequest request)
     40             throws UnsupportedEncodingException {
     41         request.setCharacterEncoding("UTF-8");//仅限POST方式.告知服务器请求正文的编码
     42         String name = request.getParameter("name");//ISO-8859-1
     43         System.out.println(name);
     44     }
     45 
     46     private void test1(HttpServletRequest request) {
     47         Student s = new Student();
     48         System.out.println("封装前："+s);
     49         try {
     50             BeanUtils.populate(s, request.getParameterMap());
     51         } catch (Exception e) {
     52             e.printStackTrace();
     53         }
     54         System.out.println("封装后："+s);
     55     }
     56 
     57     public void doPost(HttpServletRequest request, HttpServletResponse response)
     58             throws ServletException, IOException {
     59         doGet(request, response);
     60     }
     61 
     62 }

[kIhvE6V.jpg]: http://i.imgur.com/kIhvE6V.jpg
[7oqyasT.jpg]: http://i.imgur.com/7oqyasT.jpg
[20DGmlR.jpg]: http://i.imgur.com/20DGmlR.jpg
[M6yhcJH.jpg]: http://i.imgur.com/M6yhcJH.jpg
[ekVmia2.jpg]: http://i.imgur.com/ekVmia2.jpg