getInitParameter方法 静态资源参数

servlet

//获取静态初始化参数
ServletContext context = this.getServletContext();
String param = context.getInitParameter("param");
resp.getWriter().println(param);

web.xml

    <context-param>
        <param-name>param</param-name>
        <param-value>value</param-value>
    </context-param>

代码示例如下

GetInitParameter.java

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class GetInitParameter extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = this.getServletContext();

        String datasource = context.getInitParameter("datasource");
        resp.getWriter().println(datasource);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
				http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0"
         metadata-complete="true">

    <!--定义好的参数-->
    <context-param>
        <param-name>datasource</param-name>
        <param-value>jdbc:mysql://localhost:3306/test</param-value>
    </context-param>

    <servlet>
        <servlet-name>getInitParameter</servlet-name>
        <servlet-class>com.mahe666.servlet.GetInitParameter</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>getInitParameter</servlet-name>
        <url-pattern>/getInitParameter</url-pattern>
    </servlet-mapping>

</web-app>