servlet 基础之1

1.创建项目

用myeclipse创建项目open

2.配置tomcat 

 
在tomcat\conf\Catalina\localhost下添加ROOT.xml：

<?xml version='1.0' encoding='utf-8'?>
<Context crossContext="true" docBase="项目路径\WebRoot" path="" reloadable="true">
</Context>

3.在项目的WebRoot/WEB-INF/下添加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_3_0.xsd" id="WebApp_ID"
version="3.0">
<display-name>open</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

4.启动tomcat,用浏览器运行项目，结果如下：



实现最简单的HelloWorld显示功能

1）.编写类HelloWorldServlet：

package com.ben.servlet;

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;

/**
*
* @author ben1
*
*/
public class HelloWorldServlet extends HttpServlet {
private static final long serialVersionUID = 5499627704074407733L;
//信息
private String message;

public void init() throws ServletException {
// 执行必需的初始化
message = "Hello World";
}

protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// 设置响应内容类型
resp.setContentType("text/html");
//向页面输出结果
PrintWriter out=resp.getWriter();
out.print("<hr>"+message+"</hr>");
}

protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doPost(req, resp);
}

public void destory() {
//不用任何处理
}
}
2）. 在web.xml 文件中创建以下条目

<servlet>
<servlet-name>HelloWorld</servlet-name>
<servlet-class>com.ben.servlet.HelloWorldServlet</servlet-class>
</servlet>

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

3）.最后在浏览器的地址栏中输入http://localhost:8080/HelloWorld。会看到下面的结果：