Servlet技术简介之获得Servlet的初始化参数

最新推荐文章于 2021-02-12 16:47:09 发布

xiehl

最新推荐文章于 2021-02-12 16:47:09 发布

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分类专栏： Sevlet 文章标签： servlet string user url import class

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本文介绍如何在web.xml中为Servlet配置初始化参数，并通过示例展示了如何在Servlet内部获取这些参数。

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在web.xml中配置Servlet时，可以配置一些初始化参数。而在Servlet中可以通过ServletConfig接口提供的方法来取得这些参数。

现举例如下：

HelloWorldServlet.java

package jp.co.xiehl.servlet.ch7; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class HelloWorldServlet extends HttpServlet { private String driver; private String url; private String password; private String user; private static final long serialVersionUID = -5370049563045822665L; @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { PrintWriter out = resp.getWriter(); out.println("<html>"); out.println("<head>"); out.println("<title>HelloWorld</title>"); out.println("</head>"); out.println("<body bgcolor=/"lightblue/">"); out.println("<hr>"); out.println("DRVER is " + driver); out.println("URL is " + url); out.println("USER is " + user); out.println("PSSSW is " + password); out.println("</body>"); out.println("</html>"); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } @Override public void init() throws ServletException { super.init(); driver = getInitParameter("driver"); url = getInitParameter("url"); user = getInitParameter("user"); password = getInitParameter("password"); } }

web.xml配置

<servlet> <servlet-name>HelloWorld</servlet-name> <servlet-class>jp.co.xiehl.servlet.ch7.HelloWorldServlet</servlet-class> <init-param> <param-name>driver</param-name> <param-value>aaaaaa-8</param-value> </init-param> <init-param> <param-name>url</param-name> <param-value>127.1.1.1</param-value> </init-param> <init-param> <param-name>user</param-name> <param-value>ccc</param-value> </init-param> <init-param> <param-name>password</param-name> <param-value>ddd</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>HelloWorld</servlet-name> <url-pattern>/hello</url-pattern> </servlet-mapping>

执行：

http://localhost/HibernateStudy/hello

结果

画面上的信息：

DRVER is aaaaaa-8 URL is 127.1.1.1 USER is ccc PSSSW is ddd