Java Web Servlet （Part B）- ServletConfig & ServletContext（下）

<servlet>
    <servlet-name>BonjourServlet</servlet-name>
    <servlet-class>com.lilith.servlet.BonjourServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>BonjourServlet</servlet-name>
    <url-pattern>/bonjour</url-pattern>
</servlet-mapping>
<context-param>
    <param-name>username</param-name>
    <param-value>peter</param-value>
</context-param>
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protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // 获取web.xml中的上下文参数context-param
    ServletContext servletContext = getServletContext();
    String username = servletContext.getInitParameter("username");
    System.out.println("上下文参数username的值为：" + username);
    // 获取当前工程的路径
    String contextPath = servletContext.getContextPath();
    System.out.println("当期工程路径为：" + contextPath);
    // 获取部署路径
    String realPath = servletContext.getRealPath("/");
    System.out.println("当前部署路径为：" + realPath);
}
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public class SalutServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext servletContext = getServletContext();
        servletContext.setAttribute("key1","value1");
        System.out.println("在" + this.getClass() + "中获取servletContext中key1的值：" + servletContext.getAttribute("key1"));
    }
}
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<servlet>
    <servlet-name>SalutServlet</servlet-name>
    <servlet-class>com.lilith.servlet.SalutServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>SalutServlet</servlet-name>
    <url-pattern>/salut</url-pattern>
</servlet-mapping>
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public class SalutServlet2 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext servletContext = getServletContext();
        System.out.println("在" + this.getClass() + "中获取servletContext中存储的数据：" + servletContext.getAttribute("key1"));
    }
}
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<servlet>
    <servlet-name>SalutServlet2</servlet-name>
    <servlet-class>com.lilith.servlet.SalutServlet2</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>SalutServlet2</servlet-name>
    <url-pattern>/salut2</url-pattern>
</servlet-mapping>
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GET /bonjour HTTP1.1
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