Question

我正在查看Java中的Simple Servlet的示例代码。

在此示例中，Servlet由WEB-INF / web.xml文件条目

启动

<servlet-class>com.mkyong.ServletDemo1</servlet-class>



<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

    <servlet>
        <servlet-name>Servlet Name For Demo1</servlet-name>
        <servlet-class>com.mkyong.ServletDemo1</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>Servlet Name For Demo1</servlet-name>
        <url-pattern>/Demo1</url-pattern>
    </servlet-mapping>
</web-app>

我可以在main（）方法中的Java应用程序中启动（com.mkyong.ServletDemo1），调用方法。有可能吗？

感谢您的帮助。

Answer 1

是的，这是可能的。您可以使用Jetty，一个轻量级的Servlet容器。可以将Jetty嵌入到您自己的应用程序中（此示例直接取自Jetty documentation）：

public class MinimalServlets
{
    public static void main( String[] args ) throws Exception
    {
        // Create a basic jetty server object that will listen on port 8080.
        // Note that if you set this to port 0 then a randomly available port
        // will be assigned that you can either look in the logs for the port,
        // or programmatically obtain it for use in test cases.
        Server server = new Server(8080);

        // The ServletHandler is a dead simple way to create a context handler
        // that is backed by an instance of a Servlet.
        // This handler then needs to be registered with the Server object.
        ServletHandler handler = new ServletHandler();
        server.setHandler(handler);

        // Passing in the class for the Servlet allows jetty to instantiate an
        // instance of that Servlet and mount it on a given context path.

        // IMPORTANT:
        // This is a raw Servlet, not a Servlet that has been configured
        // through a web.xml @WebServlet annotation, or anything similar.
        handler.addServletWithMapping(HelloServlet.class, "/*");

        // Start things up!
        server.start();

        // The use of server.join() the will make the current thread join and
        // wait until the server is done executing.
        // See
        // http://docs.oracle.com/javase/7/docs/api/java/lang/Thread.html#join()
        server.join();
    }

    @SuppressWarnings("serial")
    public static class HelloServlet extends HttpServlet
    {
        @Override
        protected void doGet( HttpServletRequest request,
                              HttpServletResponse response ) throws ServletException,
                                                            IOException
        {
            response.setContentType("text/html");
            response.setStatus(HttpServletResponse.SC_OK);
            response.getWriter().println("<h1>Hello from HelloServlet</h1>");
        }
    }
}

Answer 2

要使用HTTPServlet，您需要像Tomcat这样的应用服务器。你不能简单地使用main方法。

Answer 3

是的，有可能!!

在代码下面，您可以执行以实现在Java类的Main方法中运行Servlet

<强> MainClass.java

import java.net.*;  
import java.io.*; 

    public class MainClass
    {  
        public static void main (String args[]) 
        { 
            String line;
            try 
            { 
                URL url = new URL( "http://localhost:8085/E/MyServlet?name=Ashok" ); 
                BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream())); 
                line = in.readLine(); 
                System.out.println( line ); 
                in.close(); 
            }
            catch (Exception e)
            { 
                e.printStackTrace(); 
            } 
        } 
    }

<强> MyServlet.java

import java.io.*; 
import javax.servlet.http.*; 
import javax.servlet.*;    
public class MyServlet extends HttpServlet 
{
    public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException
        { 
            PrintWriter out = res.getWriter(); 
            out.println ("Hello " + req.getParameter("name") + ", this is SpecialServlet!"); 
            out.close(); 
        }
    }

<强>的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    id="WebApp_ID" version="2.5">
    <display-name>E</display-name>
    <servlet>
        <servlet-name>MyServlet</servlet-name>
        <servlet-class>MyServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>MyServlet</servlet-name>
        <url-pattern>/MyServlet</url-pattern>
    </servlet-mapping>
</web-app>

将MyServlet.class放入WEB-INF - ＆gt; classes文件夹。

然后运行MainClass.java

<强>输出

您好Ashok这是SpecialServlet！

我们可以在Main方法Java Class中运行HTTPServlet

3 个答案: