Servlet笔记



慕课网学习笔记-Servlet
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1.软件结构发展史

　　1.1单机时代

　　1.2联机时代（Client-Server模式）

　　1.3互联网时代（Broswer-Server模式）

2.请问与响应、B/S模式执行流程

从浏览器发出送给服务器的数据包称为“请求 Request ”

从服务器返回给浏览器的结果称为“响应 Response ”

3.J2EE 与 Apache Tomcat

4.Servlet

　　4.1

　　　　Servlet(Server Applet)服务器小程序，主要功能用于生产动态Web内容

　　4.2　　

　　　　Servlet是J2EE最主要的组成部分，也是我们学习的重点

　　4.3Tomcat与Servlet的关系

5.第一个Servlet

 1 package com.imooc.servlet;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 
 6 import javax.servlet.ServletConfig;
 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 public class FirstServlet extends HttpServlet{
13     
14     public FirstServlet(){
15         System.out.println("正在创建FirstServlet对象");
16     }
17     
18     
19     
20     @Override
21     public void init(ServletConfig config) throws ServletException {
22         System.out.println("正在初始化FirstServlet对象");
23     }
24 
25 
26 
27     @Override
28     protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
29         //接收请求发来的参数
30         String name = request.getParameter("name");
31         String html = "<h1 style='color:red'>hi," + name +"!</h1><hr/>";
32         System.out.println("返回给浏览器的响应数据为：" + html);
33         PrintWriter out = response.getWriter();
34         out.println(html);//将html发送回浏览器
35     }
36 
37 
38 
39     @Override
40     public void destroy() {
41         System.out.println("正在销毁servlet对象");  
42     }
43 
44     
45 }

FirstServlet

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
 3   <display-name>FirstServlet</display-name>
 4   <welcome-file-list>
 5     <welcome-file>index.html</welcome-file>
 6     <welcome-file>index.htm</welcome-file>
 7     <welcome-file>index.jsp</welcome-file>
 8     <welcome-file>default.html</welcome-file>
 9     <welcome-file>default.htm</welcome-file>
10     <welcome-file>default.jsp</welcome-file>
11   </welcome-file-list>
12   <!-- 声明Servlet -->
13   <servlet>
14       <!-- servlet的别名 -->
15       <servlet-name>first</servlet-name>
16       <servlet-class>com.imooc.servlet.FirstServlet</servlet-class>
17   </servlet>
18   <!-- 将Servlet与url绑定 -->
19   <servlet-mapping>
20       <servlet-name>first</servlet-name>
21       <url-pattern>/hi</url-pattern>
22   </servlet-mapping>
23   
24    <servlet>
25       <!-- servlet的别名 -->
26       <servlet-name>sample</servlet-name>
27       <servlet-class>com.imooc.servlet.SampleServlet</servlet-class>
28   </servlet>
29   <servlet-mapping>
30       <servlet-name>sample</servlet-name>
31       <url-pattern>/sample</url-pattern>
32   </servlet-mapping>
33   
34   <servlet>
35       <!-- servlet的别名 -->
36       <servlet-name>requestMethod</servlet-name>
37       <servlet-class>com.imooc.servlet.RequestMethodServlet</servlet-class>
38   </servlet>
39   <servlet-mapping>
40       <servlet-name>requestMethod</servlet-name>
41       <url-pattern>/request_method</url-pattern>
42   </servlet-mapping>
43 </web-app>

web.xml

6.标准Java Web工程、Servlet开发步骤

7.Servlet

7.1Servlet访问方法

如：
http://localhost:8080/FirstServlet/anno

7.2请求参数

如：
http://localhost:8080/FirstServlet/sample?name=10086
&mobile=158&sex=male&spec=English&spec=Program&spec=Speech&spec=Swimming

7.3Servlet接收请求参数

如：

String sex=request.getParameter("sex");
String[] spec=request.getParameterValues("spec");

7.4Get与Post请求方法

Get请求提交的数据，可以在浏览器调试页面的Query String Parameters中查看

Post请求提交的数据，可以在浏览器调试页面的Form Data中查看

Post请求可以用于安全性较高的功能

7.5Get与Post处理方式

 1 package com.imooc.servlet;
 2 
 3 
 4 import java.io.IOException;
 5 
 6 import javax.servlet.http.HttpServlet;
 7 import javax.servlet.http.HttpServletRequest;
 8 import javax.servlet.http.HttpServletResponse;
 9 
10 
11 public class RequestMethodServlet extends HttpServlet{
12     public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException {
13         String name=request.getParameter("name");
14         response.getWriter().println("<h1 style='color:green'>"+name+"</h1>");
15     }
16     
17     public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException {
18         String name=request.getParameter("name");
19         response.getWriter().println("<h1 style='color:red'>"+name+"</h1>");
20     }
21 }

get、post

7.6应用场景

8.Servlet生命周期

 1 package com.imooc.servlet;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 
 6 import javax.servlet.ServletConfig;
 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 public class FirstServlet extends HttpServlet{
13     
14     public FirstServlet(){
15         System.out.println("正在创建FirstServlet对象");
16     }
17     
18     
19     
20     @Override
21     public void init(ServletConfig config) throws ServletException {
22         System.out.println("正在初始化FirstServlet对象");
23     }
24 
25 
26 
27     @Override
28     protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
29         //接收请求发来的参数
30         String name = request.getParameter("name");
31         String html = "<h1 style='color:red'>hi," + name +"!</h1><hr/>";
32         System.out.println("返回给浏览器的响应数据为：" + html);
33         PrintWriter out = response.getWriter();
34         out.println(html);//将html发送回浏览器
35     }
36 
37 
38 
39     @Override
40     public void destroy() {
41         System.out.println("正在销毁servlet对象");  
42     }
43 
44     
45 }

生命周期

9.使用注解配置Servlet

 1 package com.imooc.servlet;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.ServletException;
 6 import javax.servlet.annotation.WebServlet;
 7 import javax.servlet.http.HttpServlet;
 8 import javax.servlet.http.HttpServletRequest;
 9 import javax.servlet.http.HttpServletResponse;
10 
11 @WebServlet("/anno")
12 
13 public class AnnotationServlet extends HttpServlet{
14 
15     @Override
16     protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
17         // TODO Auto-generated method stub
18         resp.getWriter().println("I,m annotation servlet!");
19     }
20     
21 }

10.启动时加载Servlet

 1 package com.imooc.servlet;
 2 
 3 import javax.servlet.ServletException;
 4 import javax.servlet.annotation.WebServlet;
 5 import javax.servlet.http.HttpServlet;
 6 
 7 
 8 public class CreateServlet extends HttpServlet{
 9 
10     @Override
11     public void init() throws ServletException {
12         System.out.println("正在创建数据库");
13     }
14     
15 }

 1 package com.imooc.servlet;
 2 
 3 import javax.servlet.ServletException;
 4 import javax.servlet.annotation.WebServlet;
 5 import javax.servlet.http.HttpServlet;
 6 
 7 @WebServlet(urlPatterns="/unused",loadOnStartup=12)
 8 public class ImportServlet extends HttpServlet{
 9 
10     @Override
11     public void init() throws ServletException {
12         System.out.println("正在导入数据");
13     }
14     
15 }

 注解必须，两个参数
@WebServlet(urlPatterns="/unused",loadOnStartup=12)