servlet 入门（在网页中显示”hello servlet"）

1、在tomcat中新建一个web应用（如名字为servlet0_1）,然后在web应用中新建一个WEB-INF/classes目录。

2、在classes目录中新建一个servlet_1.java

package  servletdemo

import java.io.*;

import java.servlet.*;

public class servlet_1 extends GenericServlet{

    public void service (ServletRepuest reg, ServletResponse res) throws ServletException, java.io.IOException{

         OutputStream out =res.getOutputStream();

         out.write("hello servlet !".getByte()); 

   }

}

3、set classpath=%classpath%;```````````````servlet.jar    编译servlet

4、在WEB-INF目录中新建web.xml配置文件，配置servlet  的对外访问路径

<?xml version='1.0' encoding='utf-8'?>

<web-app xmlns="http://java.sun.com/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                      http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
  version="3.0">

 <servlet>
        <servlet-name>servlet_1</servlet-name>
        <servlet-class>servletdemo.servlet_1</servlet-class>
    </servlet>

<servlet-mapping>
        <servlet-name>servlet_1</servlet-name>
        <url-pattern>/servlet_1</url-pattern>
    </servlet-mapping>

</web-app>

5、启动tomcat，访问