Java Servlet 初学者快速入门指南（注解）

Dear 丶 2023-09-30 08:53 12阅读 0赞

[在本 Java 教程中，我将帮助您使用@WebServlet][Java _WebServlet]注释从头开始开发 Java servlet，以及如何在 Tomcat 服务器上部署、运行和测试 servlet。

本教程与[Java servlet 初学者快速入门指南 (XML)][Java servlet _ _XML]类似，不同之处在于 servlet 配置和映射是通过注解而不是在web.xml文件中完成的。没有使用 XML 的东西。

**表中的内容：**

1.  servlet注解快速介绍
2.  创建目录结构
3.  编写带注释的 servlet 类
4.  编写 JSP 页面
5.  编译servlet
6.  创建 WAR 文件
7.  部署和测试 Web 应用程序

### **1. servlet注解快速介绍** ###

Servlet API 3.0 引入了一个名为javax.servlet.annotation的新包，它提供了可用于注释 servlet 类的注释类型。注释可以替换 Web 部署描述符文件 ( web.xml ) 中的等效 XML 配置，例如 servlet 声明和 servlet 映射。Servlet 容器将在部署时处理带注释的类。

Servlet 3.0 中引入的注解类型有：

*  [@HandlesTypes][HandlesTypes]
 *  [@ServletSecurity、@HttpMethodConstraint 和 @HttpConstraint][ServletSecurity_HttpMethodConstraint _ _HttpConstraint]
 *  [@MultipartConfig][MultipartConfig]
 *  [@WebFilter][WebFilter]
 *  [@WebInitParam][WebInitParam]
 *  [@WebListener][WebListener]
 *  [@WebServlet][Java _WebServlet]

注解@WebServlet用于声明一个servlet 类（该类仍然必须从HttpServlet类扩展）并为其配置映射。以下是使用@WebServlet注解的一些示例：

*  声明 servlet 的最简单方法：
    
    <table> 
     <tbody> 
      <tr> 
       <td style="text-align:left;vertical-align:baseline;"> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">1</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">2</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">3</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">4</span></span> 
        </div> </td> 
       <td style="text-align:left;vertical-align:baseline;"> 
        <div style="margin-left:0;text-align:left;"> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>@WebServlet</code><code>(</code><code>"/Submit"</code><code>)</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>public</code> <code>class</code> <code>QuickServlet&nbsp;</code><code>extends</code> <code>HttpServlet { </code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>// servlet code here...</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>}</code></span></span> 
         </div> 
        </div> </td> 
      </tr> 
     </tbody> 
    </table>
    
      
    这里 servlet QuickServlet 映射到 URL 模式：*/Submit。*
 *  声明一个带有附加信息的 servlet：
    
    <table> 
     <tbody> 
      <tr> 
       <td style="text-align:left;vertical-align:baseline;"> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">1</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">2</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">3</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">4</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">5</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">6</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">7</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">8</span></span> 
        </div> </td> 
       <td style="text-align:left;vertical-align:baseline;"> 
        <div style="margin-left:0;text-align:left;"> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>@WebServlet</code><code>(</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>name =&nbsp;</code><code>"AnnotatedServlet"</code><code>,</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>description =&nbsp;</code><code>"A sample annotated servlet"</code><code>,</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>urlPatterns = { </code><code>"/QuickServlet"</code><code>}</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>)</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>public</code> <code>class</code> <code>QuickServlet&nbsp;</code><code>extends</code> <code>HttpServlet { </code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>// servlet code here...</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>}</code></span></span> 
         </div> 
        </div> </td> 
      </tr> 
     </tbody> 
    </table>
    
    此处的 servlet 声明了附加信息，例如名称和描述。
 *  声明一个具有多个 URL 模式的 servlet：
    
    <table> 
     <tbody> 
      <tr> 
       <td style="text-align:left;vertical-align:baseline;"> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">1</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">2</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">3</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">4</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">5</span></span> 
        </div> 
        <div style="margin-left:0;text-align:right;"> 
         <span style="background-color:#FFFFFF;"><span style="color:#787878;">6</span></span> 
        </div> </td> 
       <td style="text-align:left;vertical-align:baseline;"> 
        <div style="margin-left:0;text-align:left;"> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>@WebServlet</code><code>(</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>urlPatterns = { </code><code>"/foo"</code><code>,&nbsp;</code><code>"/bar"</code><code>,&nbsp;</code><code>"/cool"</code><code>}</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>)</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>public</code> <code>class</code> <code>QuickServlet&nbsp;</code><code>extends</code> <code>HttpServlet { </code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>// servlet code here...</code></span></span> 
         </div> 
         <div style="margin-left:0;text-align:left;"> 
          <span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>}</code></span></span> 
         </div> 
        </div> </td> 
      </tr> 
     </tbody> 
    </table>
    
      
    此处 servlet 使用三种不同的 URL 模式进行映射：*/foo*、*/bar*和*/cool*。

现在让我们构建一个简单的 Java Web 应用程序，它有一个使用@WebServlet注释配置的 servlet。假设您的计算机上安装了[JDK 1.7][]和[Tomcat 7.0 。][Tomcat 7.0]当然，您可以使用较新的版本。

### **2.创建目录结构** ###

由于我们不使用任何 IDE，因此创建以下目录结构：

![226492cda4439b539b3de487bf816f0d.png][]

并假设当前工作目录是QuickServlet目录。

###    **3.编写带注释的servlet类** ###

在src\\net\\code\\java\\servlet目录下创建名为QuickServlet.java的 servlet 类。粘贴以下代码：

<table> 
 <tbody> 
  <tr> 
   <td style="text-align:left;vertical-align:baseline;"> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">1</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">2</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">3</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">4</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">5</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">6</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">7</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">8</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">9</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">10</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">11</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">12</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">13</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">14</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">15</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">16</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">17</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">18</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">19</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">20</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">21</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">22</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">23</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">24</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">25</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">26</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">27</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">28</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">29</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">30</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">31</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">32</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">33</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">34</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">35</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">36</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">37</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">38</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">39</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">40</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">41</span></span></span></span> 
    </div> 
    <div style="margin-left:0;text-align:right;"> 
     <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="color:#787878;">42</span></span></span></span> 
    </div> </td> 
   <td style="text-align:left;vertical-align:baseline;"> 
    <div style="margin-left:0;text-align:left;"> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>package</code> <code>net.codejava.servlet;</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>import</code> <code>java.io.IOException;</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>import</code> <code>java.io.PrintWriter;</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>import</code> <code>javax.servlet.annotation.WebServlet;</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>import</code> <code>javax.servlet.http.HttpServlet;</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>import</code> <code>javax.servlet.http.HttpServletRequest;</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>import</code> <code>javax.servlet.http.HttpServletResponse;</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>@WebServlet</code><code>(</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>name =&nbsp;</code><code>"AnnotatedServlet"</code><code>,</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>description =&nbsp;</code><code>"A sample annotated servlet"</code><code>,</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>urlPatterns = { </code><code>"/QuickServlet"</code><code>}</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>)</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>public</code> <code>class</code> <code>QuickServlet&nbsp;</code><code>extends</code> <code>HttpServlet { </code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code> <code>void</code> <code>doGet(HttpServletRequest request, HttpServletResponse response)</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>throws</code> <code>IOException { </code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>PrintWriter writer = response.getWriter();</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>writer.println(</code><code>"&lt;html&gt;Hello, I am a Java servlet!&lt;/html&gt;"</code><code>);</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>writer.flush();</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code> <code>void</code> <code>doPost(HttpServletRequest request, HttpServletResponse response)</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>throws</code> <code>IOException { </code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>String paramWidth = request.getParameter(</code><code>"width"</code><code>);</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>int</code> <code>width = Integer.parseInt(paramWidth);</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>String paramHeight = request.getParameter(</code><code>"height"</code><code>);</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>int</code> <code>height = Integer.parseInt(paramHeight);</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>long</code> <code>area = width * height;</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>PrintWriter writer = response.getWriter();</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>writer.println(</code><code>"&lt;html&gt;Area of the rectangle is: "</code> <code>+ area +&nbsp;</code><code>"&lt;/html&gt;"</code><code>);</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>writer.flush();</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;">&nbsp;</span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code></span></span></span></span> 
     </div> 
     <div style="margin-left:0;text-align:left;"> 
      <span style="color:#333333;"><span style="background-color:#ffffff;"><span style="background-color:#FFFFFF;"><span style="background-color:#ffffff;"><code>}</code></span></span></span></span> 
     </div> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

### **4.编写JSP页面** ###

在WebContent目录下，使用以下代码创建一个名为index.jsp的 JSP 文件：

### **5. 编译servlet** ###

键入以下命令来编译 servlet 类：

**javac -cp *TOMCAT\_HOME* \\lib\\servlet-api.jar" -d *CLASS\_DIR* *SRC\_DIR* \\QuickServlet.java**

代替：

*  *TOMCAT\_HOME =* C:\\Program Files\\Apache Software Foundation\\Tomcat 7.0*。*
 *  *CLASS\_DIR* =WebContent \\ WEB-INF \\ 类
 *  *SRC\_DIR* =src\\net\\codejava\\servlet

###    **6. 创建WAR文件** ###

键入以下命令，将WebContent目录打包为 WAR 文件（注意末尾有一个点）：

**jar cfv deploy\\QuickServletApp.war -C WebContent 。**

请注意，没有web.xml文件，因为我们使用了@WebServlet注解来声明和映射 servlet。

###    **7. 部署和测试 Java servlet** ###

请参阅教程：[Java servlet 初学者快速入门指南 (XML)][Java servlet _ _XML]以部署和测试应用程序。

[Java _WebServlet]: https://mail.codejava.net/java-ee/servlet/webservlet-annotation-examples
[Java servlet _ _XML]: https://mail.codejava.net/java-ee/servlet/java-servlet-quick-start-tomcat-xml-config
[HandlesTypes]: https://mail.codejava.net/java-ee/servlet/handlestypes-annotation-examples
[ServletSecurity_HttpMethodConstraint _ _HttpConstraint]: https://mail.codejava.net/java-ee/servlet/servletsecurity-httpmethodcontraint-and-httpconstraint-annotations-examples
[MultipartConfig]: https://mail.codejava.net/java-ee/servlet/multipartconfig-annotation-examples
[WebFilter]: https://mail.codejava.net/java-ee/servlet/webfilter-annotation-examples
[WebInitParam]: https://mail.codejava.net/java-ee/servlet/webinitparam-annotation-examples
[WebListener]: https://mail.codejava.net/java-ee/servlet/weblistener-annotation-examples
[JDK 1.7]: http://www.oracle.com/technetwork/java/javase/downloads/java-se-jdk-7-download-432154.html
[Tomcat 7.0]: https://tomcat.apache.org/download-70.cgi
[226492cda4439b539b3de487bf816f0d.png]: https://img-blog.csdnimg.cn/img_convert/226492cda4439b539b3de487bf816f0d.png