获取和配置Servlet的初始化参数

港控/mmm° 2024-04-06 11:16 78阅读 0赞

配置Servlet的初始化参数有两种：

1、使用注解方式@WebServlet

在注解中设置Servlet的初始化参数，需要配置name,urlPatterns,inintParams的值

name等价于web.xml配置文件中的<servlet-name>

urlPatterns等价于<url-pattern>，用于指定servlet的URL

inintParams等价于<init-pattern>，用于指定一组servlet初始化参数

@WebServlet(
    name="/initParameterServlet", //name="/自定义"
    urlPatterns={"/initParameterServlet"}, //urlPatterns={"/自定义"}
    initParams={
    @WebInitParam
    (name="email",value = "123qq.com")  //name="设置的参数名"   value="设置的参数值"
    })

如果需要配置多组参数，可以如下操作：

@WebServlet(
    name="/InitParameterServlet",
    urlPatterns={"/initParameterServlet"},
    initParams={
    @WebInitParam
    (name="email",value = "12345@qq.com"),
    @WebInitParam
    (name="phone",value = "123456789"),
    @WebInitParam
    (name="参数名",value = "参数值")
    })

servlet完整代码如下：

public class InitParameterServlet extends HttpServlet {
    
    	@Override
    	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    		 ServletConfig config = this.getServletConfig();
    		 String value = config.getInitParameter("email");
    		 
    		 String value1 = config.getInitParameter("phone");
    		 PrintWriter writer = resp.getWriter();
    		 writer.println("your email is:"+value);
    		 writer.println("your phone munber is:"+value1);
    	}
    
    	@Override
    	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    		doGet(req, resp);
    	}
    
    }

地址栏输入：http://主机名:端口号/工程名/urlPatterns设置的值

实现如下：

![39d8126f5af84cc58cd5d776c9bddbb8.png][]

2、在Web.xml文件中配置

<servlet-class>：注册的servlet 的类地址，也就是：包名.类名

配置初始化参数是在

<context-param>

<param-name>属性名</param-name>  
<param-value>属性值</param-value>

</context-param>

需要配置多少个参数就写多少个<context-param>....</context-param>

Web.xml配置文件加入以下代码部分：

<servlet>
    		<servlet-name>InitParameterServlet1</servlet-name>
    		<servlet-class>com.servlet.InitParameterServlet1</servlet-class>
        </servlet>
    	<servlet-mapping>
    		<servlet-name>InitParameterServlet1</servlet-name>
    		<url-pattern>/initParameterServlet1</url-pattern>
    	</servlet-mapping> 
    	
    	<context-param>
    		<param-name>email</param-name>
    		<param-value>123qq.com</param-value>
    	</context-param>

servlet完整代码如下：

public class InitParameterServlet1 extends HttpServlet{
    
    	@Override
    	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    		ServletContext servletContext = getServletContext();
    		String initParameter = servletContext.getInitParameter("email");
            String initParameter1 = servletContext.getInitParameter("phone");
    		
    		//后台
    		System.out.println("your email is:" + initParameter);
    		System.out.println("your phone number is:" + initParameter1);
    
    		//浏览器
    		PrintWriter writer = resp.getWriter();
    		writer.println("your email is" + initParameter);
            writer.println("your phone number  is" + initParameter1);
    	}
    }

效果同上

仅供参考，如有不足之处，敬请见谅。

[39d8126f5af84cc58cd5d776c9bddbb8.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/06/8b8d255e25be4e939e1f8468db5f55e6.png