第2階段第13講 Servlet進階(上)

課程回顧

XML解析: DOM4J、DOM、SAX、JDOM, getParent() 獲取父節點，再刪除

HTTP協議: 0.9、1.0、1.1 無狀態協議

反射技術: Class類反射入口、獲取類信息、屬性信息、方法信息、構造方法信息、main方法、創建對象(newInstance())、調用方法( invoke )、強制訪問( setAccessible(true) )

動態代理: Proxy.newInstance( 類加載器, 接口數組，InvocationHandler ) MyBatis框架使用動態代理、SpringAOP也是

概述

我們在編寫Servlet的時候，重寫的doGet方法、doPost方法包括兩個參數: HttpServletRequest, HttpServletResponse ;這兩個參數表示的請求和響應對象。請求和響應對象的創建是由Tomcat服務器來實現的，我們開發人員並不需要顯示的創建這兩個對象；可以直接使用。Web服務器收到一個http請求，會針對每個請求創建一個HttpServletRequest和HttpServletResponse對象，從客戶端取數據找HttpServletRequest，向客戶端發送數據就是HttpServletResponse。

特別感謝: CSDN博客——揚俊的小屋做的動畫

HttpServletResponse接口

接口定義

public interface HttpServletResponse extends ServletResponse

所在的包： javax.servlet.http,常見的屬性和方法見文檔。

HttpServletResponse對象代表服務器的響應。該對象可以向客戶端發送三種類型的數據:

響應頭：響應的頭部信息
響應碼：響應的狀態碼
響應體：響應的具體數據

查看HttpServletResponse的API，可以看到這些相關的方法。查看響應的相關信息:

發送響應頭

package com.ujiuye.web;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;

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

@WebServlet("/resp2")
public class MyResponse2 extends HttpServlet {
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		String str = "對於IO操作來說，使用頻率最高（也是最容易被遺忘）的就是close操作，好在Java規範使用了優雅的Closeable接口，這樣我們只需簡單封裝調用此接口的方法即可。";
		System.out.println("原始字節長度:"+str.getBytes().length);
		//創建字節數組輸出流,作爲容器，默認長度32個字節
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		//創建壓縮輸出流,壓縮，不存儲
		GZIPOutputStream zip = new GZIPOutputStream(bos);
		//將原始字符串寫到壓縮輸出流
		zip.write(str.getBytes());
		zip.close();
		//把容器轉換成字節數組
		byte[] array = bos.toByteArray();
		System.out.println("壓縮後的長度:"+array.length);
		//操作響應頭
		response.setHeader("Content-Encoding", "gzip");
		response.setHeader("Content-Length", array.length+"");
		response.setHeader("Accept-Range", "bytes");
		response.setHeader("Cache-Control", "no-cache");
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

執行結果:

發送響應頭控制瀏覽器內容類型

text/html;charset=utf8 文本或者HTML代碼
jpeg 圖片格式
pdf pdf文件

內容類型參考文件: apache-tomcat-8.5.51/conf/web.xml

package com.ujiuye.web;

import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/image")
public class MyResponseImage extends HttpServlet {
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//設置響應頭
		response.setHeader("Content-Type", "jpeg");
		//加載圖片獲取輸入流
		InputStream in = this.getServletContext().getResourceAsStream("/WEB-INF/01.jpeg");
		//創建緩衝數組
		byte[] b = new byte[1024];
		//定義讀取數據長度
		int len = 0;
		//循環讀取並寫到瀏覽器
		ServletOutputStream sos =  response.getOutputStream();
		while( (len=in.read(b) ) != -1) {
			sos.write(b, 0, len);
		}
		sos.close();
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

http://localhost:8080/chapter13/image

發送響應頭控制瀏覽器禁止緩存

protected void doGet(HttpServletRequest req, HttpServletResponse response) throws ServletException, IOException { 
	response.setDateHeader("expries", -1);
	response.setHeader("Cache-Control", "no-cache");
	response.setHeader("Pragma", "no-cache");
}

發送響應頭控制瀏覽器定時刷新

protected void doGet(HttpServletRequest req, HttpServletResponse response) throws ServletException, IOException { 
	response.setHeader("refresh", "5");//設置refresh響應頭控制瀏覽器每隔5秒鐘刷新一次
    //response.setHeader("refresh", "3;url=https://www.baidu.com");//3秒鐘跳轉頁面
}

發送響應碼

Servlet在接收用戶請求並進行業務處理之後要轉向到另一個頁面，譬如成功或失敗頁面，這個頁面跳轉過程稱爲重定向。HttpServletResponse中一般用sendRedirect進行重定向，也就是跳轉到另一個頁面或者Servlet。sendRedirect進行重定向做了下面2件事：

設置HTTP響應報頭中的Status爲302
設置HTTP響應報頭中的Location值爲指定的URL

HttpServletResponse定義了很多狀態碼的常量(具體可以查看Servlet的API)，當需要向客戶端發送響應狀態碼時，可以使用這些常量，避免了直接寫數字，常見的狀態碼對應的常量：

狀態碼404對應的常量 SC_NOT_FOUND
狀態碼200對應的常量 SC_OK
狀態碼500對應的常量 SC_INTERNAL_SERVER_ERROR

用法

HttpServletResponse.sendRedirect("url?參數名1=參數值&參數名2=參數值");

實例

protected void doGet(HttpServletRequest request,  
	HttpServletResponse response) throws ServletException, IOException {  
	/*方法一：使用response.sendRedirect*/  
	//response.sendRedirect("index.html");  
	  
	/*方法二：設置響應頭和重定向地址*/  
	response.setHeader("Location", "index.html");  
	response.setStatus(HttpServletResponse.SC_FOUND);//設置302狀態碼，等同於response.setStatus(302);       
}

發送響應體

通過response對象返回具體數據到瀏覽器是需要的數據傳輸媒介，分爲: 字節流和字符流。

package com.ujiuye.web;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/refresh")
public class MyResponseRefresh extends HttpServlet {
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("text/html;charset=utf8");
        /**
         * 多學一招：使用HTML語言裏面的標籤來控制瀏覽器行爲，模擬通過設置響應頭控制瀏覽器行爲
		 * response.setHeader("content-type", "text/html;charset=UTF-8");
         */
		String str = "3秒鐘跳轉頁面";
		//輸出中文: 字節流
        //ServletOutputStream sos = response.getOutputStream();
        //sos.write(str.getBytes());
        //out.write("使用OutputStream輸出數字:".getBytes("utf-8"));
        //out.write( (1+"").getBytes());//字母d， 
		//字符流
		PrintWriter out = response.getWriter();
		out.println("字符流:" + str);
		
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

注意：getOutputStream()和getWriter()這兩個方法互相排斥，調用了其中的任何一個方法後，就不能再調用另一方法。

綜合案例：文件下載

編寫Servlet

package com.ujiuye.web;

import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/download")
public class MyResponseDownload extends HttpServlet {
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//設置文件下載響應頭
		response.setHeader("Content-disposition", "attachment;filename=01.jpeg");
		//加載圖片獲取輸入流
		InputStream in = getServletContext().getResourceAsStream("/WEB-INF/01.jpeg");
		//獲取輸出流
		ServletOutputStream out = response.getOutputStream();
		//創建緩衝池
		byte[] b = new byte[1024];
		int len = 0;
		while(  (len = in.read(b)) != -1 ) {
			out.write(b, 0, len);
		}
		out.close();
        in.close();
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

編寫HTML頁面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="download">文件下載</a>
</body>
</html>

支持中文文件名

package com.ujiuye.web;

import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLEncoder;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/download")
public class MyResponseDownload extends HttpServlet {
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//加載圖片獲取輸入流
		String realPath = getServletContext().getRealPath("/WEB-INF/美女.jpeg");
		String fileName = realPath.substring(realPath.lastIndexOf("/") + 1);
		System.out.println("文件名稱:"+fileName);
		//設置文件下載響應頭
		response.setHeader("Content-disposition", "attachment;filename="+URLEncoder.encode(fileName, "utf-8"));
		
		//InputStream in = getServletContext().getResourceAsStream("/WEB-INF/01.jpeg");
		
		//獲取流
		FileInputStream in  = new FileInputStream(realPath);
		ServletOutputStream out = response.getOutputStream();
		//創建緩衝池
		byte[] b = new byte[1024];
		int len = 0;
		while(  (len = in.read(b)) != -1 ) {
			out.write(b, 0, len);
		}
		in.close();
		out.close();
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

綜合案例：圖片驗證碼

package com.ujiuye.web;

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.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/code")
public class MyResponseCode extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// 0.設置refresh響應頭控制瀏覽器每隔5秒鐘刷新一次
		response.setHeader("refresh", "5");
		// 1.在內存中創建一張圖片
		BufferedImage image = new BufferedImage(80, 20, BufferedImage.TYPE_INT_RGB);
		// 2.得到圖片
		// Graphics g = image.getGraphics();
		Graphics2D g = (Graphics2D) image.getGraphics();
		g.setColor(Color.WHITE);// 設置圖片的背景色
		g.fillRect(0, 0, 80, 20);// 填充背景色
		// 3.向圖片上寫數據
		g.setColor(Color.BLUE);// 設置圖片上字體的顏色
		g.setFont(new Font(null, Font.BOLD, 20));
		g.drawString(makeNum(), 0, 20);
		// 4.設置響應頭控制瀏覽器瀏覽器以圖片的方式打開
		response.setContentType("image/jpeg");// 等同於response.setHeader("Content-Type", "image/jpeg");
		// 5.設置響應頭控制瀏覽器不緩存圖片數據
		response.setDateHeader("expries", -1);
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Pragma", "no-cache");
		// 6.將圖片寫給瀏覽器
		ImageIO.write(image, "jpg", response.getOutputStream());
	}

	/**
	 * 生成隨機數字
	 */
	private String makeNum() {
		Random random = new Random();
		String num = random.nextInt(9999999) + "";
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < 7 - num.length(); i++) {
			sb.append("0");
		}
		num = sb.toString() + num;
		return num;
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

訪問地址: http://localhost:8080/chapter13/code

HttpServletRequest接口

接口定義

HttpServletRequest接口的定義

public interface HttpServletRequest extends ServletRequest

父接口: ServletRequest接口的定義, 從定義可以看出ServletRequest是根接口。

public interface ServletRequest

Defines an object to provide client request information to a servlet. The servlet container creates a ServletRequest object and passes it as an argument to the servlet’s service method.

定義一個提供客戶端請求信息到一個Servlet的對象，Servlet容器創建一個ServletRequest對象並作爲一個參數傳遞給Servlet的seivice方法。

A ServletRequest object provides data including parameter name and values, attributes, and an input stream. Interfaces that extend ServletRequest can provide additional protocol-specific data (for example, HTTP data is provided by HttpServletRequest.

一個ServletRequest對象提供的數據包括: 參數名稱和參數值、屬性值、輸入流。繼承自ServletRequest接口可以提供額外指定的協議參數，( 例如Http協議 )

實現類: HttpServletRequestWrapper

public class HttpServletRequestWrapper extends ServletRequestWrapper
    implements HttpServletRequest

查看請求的相關信息:

獲取請求行信息

package com.ujiuye.web2;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/line")
public class RequestLine extends HttpServlet {

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String scheme   = request.getScheme();//獲取協議
		String method   = request.getMethod(); //請求方法
		String url      = request.getRequestURL().toString();//請求的URL
		String uri      = request.getRequestURI();//請求的URI
		String param    = request.getQueryString();//請求的參數
		String protocol = request.getProtocol();//請求的協議
		String path     = request.getContextPath();//獲取項目名稱
		response.setContentType("text/html;charset=utf8");
		PrintWriter out = response.getWriter();
        out.println("scheme:"   + scheme + "<br/>");
		out.println("method:"   + method + "<br/>");
		out.println("url:"      + url + "<br/>");
		out.println("uri:"      + uri + "<br/>");
		out.println("param:"    + param + "<br/>");
		out.println("protocol:" + protocol + "<br/>");
		out.println("path:"     + path + "<br/>");
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

http://localhost:8080/chapter13/line?username=admin&password=123456

獲取請求頭信息

獲取請求的報文頭信息：

request.getHeader(“xx”) 根據指定的請求頭獲取值
request.getHeaders(“xx”)根據指定的請求頭獲取值,值是多個；Accept-Language: zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6
request.getHeaderNames()獲取所有的請求頭的名稱，然後就可以根據名稱再獲取值

package com.ujiuye.web2;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/header")
public class RequestHeader extends HttpServlet {

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("text/html;charset=utf8"); 
		PrintWriter out = response.getWriter();
		Enumeration<String> en =  request.getHeaderNames();//Iterator
		 while(en.hasMoreElements()) {
			String name =  en.nextElement();
			String value = request.getHeader(name);
			out.println(name + "-->" + value + "<br/>");
		 }
		 out.close();
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

執行結果:

獲取請求體信息

獲得客戶機請求參數(客戶端提交的數據)

getParameter(String)方法**(常用)**
getParameterValues(String name)方法**(常用)**
getParameterNames()方法(不常用)
getParameterMap()方法**(編寫框架時常用)**

註冊頁面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="download">文件下載</a>

<h1>用戶註冊</h1>
<form name="regForm" action="registerServlet" method="post" id="regForm">
姓名: <input type="text" name="name" id="name"><br>
性別: 男<input type="radio" name="sex" id="radio1" value="男" checked>
     女<input type="radio" name="sex" id="radio2" value="女"><br>
愛好: 
抽菸<input type="checkbox" name="hobbies" value="抽菸">
喝酒<input type="checkbox" name="hobbies" value="喝酒">
打豆豆<input type="checkbox" name="hobbies" value="打豆豆" checked>
泡妞<input type="checkbox" name="hobbies" value="泡妞"><br/>
簡介: <textarea name="mark" id="" cols="30" rows="10"></textarea><br>
學歷: <select name="education" id="selEdu">
    <optgroup label="非正常學歷">
        <option value="野雞大學">野雞大學</option>
        <option value="家裏蹲大學">家裏蹲大學</option>
        <option value="社會大學">社會大學</option>
    </optgroup>
    <optgroup label="正常學歷">
        <option value="初中">初中</option>
        <option value="高中" selected="selected">高中</option>
        <option value="大學">大學</option>
    </optgroup>
</select><br>
<input type="submit" value="提交"/>
<input type="reset" value="重置"/>
</form>
</body>
</html>

註冊Servlet

package com.ujiuye.web2;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.Map;

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

@WebServlet("/registerServlet")
public class RequestBody extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("utf-8");
		response.setContentType("text/html;charset=utf-8");
		PrintWriter out = response.getWriter();
		//第一種方法: 根據表單組件名稱獲取值
		String name      = request.getParameter("name");
		String sex       = request.getParameter("sex");
		String hobbies[] = request.getParameterValues("chk_hobbies");
		String mark      = request.getParameter("mark");
		String edu       = request.getParameter("education");
		
		out.println("name:" + name + "<br/>");
		out.println("sex:" + sex + "<br/>");
		out.println("hobbies:" + Arrays.toString(hobbies) + "<br/>");
		out.println("mark:" + mark + "<br/>");
		out.println("edu:" + edu + "<br/>");
		out.println("<hr/>");
		//第二種方法: 如果表單的內容不詳，如何獲取表單數據？ Map
		Map<String,String[]> map = request.getParameterMap();
		for(Map.Entry<String, String[]> entry : map.entrySet()) {
			String names = entry.getKey();
			String values[] = entry.getValue();
			out.println(names + "--->" + Arrays.toString(values).replace("[", "").replace("]", "")+"<br/>");
		}
		//第三種方法: 先獲取所有的名稱，再跟據名字獲取內容
		out.println("<hr/>");
		Enumeration<String> en =  request.getParameterNames();
		while(en.hasMoreElements()) {
			String namess = en.nextElement();
			if(namess.startsWith("chk_")) {
				String [] values = request.getParameterValues(namess);
				out.println(namess + "--->" + 
                            Arrays.toString(values).replace("[", "").replace("]", "")+"<br/>");
			}else {
				String value = request.getParameter(namess);//多選的問題
				out.println(namess + "--->" + value+"<br/>");
			}
		}
		out.close();
	}
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

執行效果

獲取請求客戶端信息

package com.ujiuye.web2;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/remote")
public class RequestRemote  extends HttpServlet{

	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		String addr = request.getRemoteAddr();//客戶端IP地址
		String host = request.getRemoteHost();//客戶端主機
		int port    = request.getRemotePort();//客戶端端口
		String user = request.getRemoteUser();//客戶端用戶名稱
		
		request.setCharacterEncoding("utf-8");
		response.setContentType("text/html;charset=utf-8");
		PrintWriter out = response.getWriter();
		out.println("addr:" + addr+"<br/>");
		out.println("host:" + host+"<br/>");
		out.println("port:" + port+"<br/>");
		out.println("user:" + user+"<br/>");
	}
}

獲取本地服務器信息

package com.ujiuye.web2;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Locale;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/local")
public class RequestLocal  extends HttpServlet{

	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		String addr = request.getLocalAddr();//服務器IP
		String host = request.getLocalName();//服務器名稱
		int port    = request.getLocalPort();//服務器端口
		
		//具體的服務器
		String serverName = request.getServerName();
		int serverPort    = request.getServerPort();
		//代表的本地信息，國家、語言
		Locale local = request.getLocale();
		
		request.setCharacterEncoding("utf-8");
		response.setContentType("text/html;charset=utf-8");
		PrintWriter out = response.getWriter();
		out.println("addr:" + addr+"<br/>");
		out.println("host:" + host+"<br/>");
		out.println("port:" + port+"<br/>");
		out.println("local:" + local.getDisplayCountry() + ","+
                               local.getDisplayLanguage() +"<br/>");
		
		out.println("serverName:" + serverName+"<br/>");
		out.println("serverPort:" + serverPort+"<br/>");
	}
}

第2階段第13講 Servlet進階(上)

課程回顧

概述

HttpServletResponse接口

接口定義

發送響應頭

發送響應頭控制瀏覽器內容類型

發送響應頭控制瀏覽器禁止緩存

發送響應頭控制瀏覽器定時刷新

發送響應碼

用法

實例

發送響應體

綜合案例：文件下載

編寫Servlet

編寫HTML頁面

支持中文文件名

綜合案例：圖片驗證碼

HttpServletRequest接口

接口定義

獲取請求行信息

獲取請求頭信息

獲取請求體信息

註冊頁面

註冊Servlet

執行效果

獲取請求客戶端信息

獲取本地服務器信息

工作中用到的腳本合集

24-5-18 X

第1章初始JAVA

第20章類加載器

第25章 JDBC核心技術第4節：操作BLOB類型字段

設計模式之三模板方法

設計模式之六觀察者模式

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

linux以太網驅動總結

第2階段 第13講 Servlet進階(上)

課程回顧

概述

HttpServletResponse接口

接口定義

發送響應頭

發送響應頭控制瀏覽器內容類型

發送響應頭控制瀏覽器禁止緩存

發送響應頭控制瀏覽器定時刷新

發送響應碼

用法

實例

發送響應體

綜合案例：文件下載

編寫Servlet

編寫HTML頁面

支持中文文件名

綜合案例：圖片驗證碼

HttpServletRequest接口

接口定義

獲取請求行信息

獲取請求頭信息

獲取請求體信息

註冊頁面

註冊Servlet

執行效果

獲取請求客戶端信息

獲取本地服務器信息

第2階段第13講 Servlet進階(上)