Servlet详细介绍
1 <?xml version="1.0" encoding="UTF-8"?> 2 <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 5 http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> 6 <display-name></display-name> 7 <welcome-file-list> 8 <welcome-file>index.jsp</welcome-file> 9 </welcome-file-list> 10 11 <servlet> 12 <servlet-name>date</servlet-name> 13 <servlet-class>date.DateDemo</servlet-class> 14 </servlet> 15 <servlet-mapping> 16 <servlet-name>date</servlet-name> 17 <url-pattern>*.do</url-pattern> 18 </servlet-mapping> 19 </web-app>
1 package date; 2 3 import java.io.IOException; 4 import java.io.PrintWriter; 5 import java.text.SimpleDateFormat; 6 import java.util.Date; 7 8 import javax.servlet.ServletException; 9 import javax.servlet.http.HttpServlet; 10 import javax.servlet.http.HttpServletRequest; 11 import javax.servlet.http.HttpServletResponse; 12 13 @SuppressWarnings("serial") 14 public class DateDemo extends HttpServlet { 15 16 17 @Override 18 protected void service(HttpServletRequest request, HttpServletResponse response) 19 throws ServletException, IOException { 20 response.setContentType("text/html"); 21 PrintWriter p=response.getWriter(); 22 Date now=new Date(); 23 SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd"); 24 String time=sdf.format(now); 25 p.write(time); 26 p.close(); 27 } 28 29 }
1）Servlet实际上就是一个容器，Tomcat就是一个Servlet，它提供了Servlet运行的环境
2）关于Servlet路径的认识---Servlet是如何运行的
2.1比如在浏览器中输入: http://localhost:8080/Servlet2/hi
1,浏览器通过ip,port与Servlet建立连接
2,浏览器将请求参数打包发送给Servlet容器。
3,Servlet解析请求数据，并将该数据放到request对象上，同时创建response对象
4,Servlet会通过配置(Servlet2/hi)找到配置文件，然后创建对应的Servlet对象。
5,Servlet容器自动调用service方法，处理request对象，并且返回给response对象
6,Servlet容器打包resopnse数据，返回给浏览器。
7,浏览器给句数据展示给用户。
Java代码：
package date;
import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@SuppressWarnings("serial")
public class DateDemo extends HttpServlet {
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter p=response.getWriter();
Date now=new Date();
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
String time=sdf.format(now);
p.write(time);
p.close();
}
}
web.xml配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 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_2_5.xsd">
<display-name></display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>date</servlet-name>
<servlet-class>date.DateDemo</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>date</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app>
