J2EE 第2次课笔记--Servlet

这次课讲了一些servlet一些基础的知识!
1.在本地访问servlet(以tomcat服务器为例):
http://locatlhost:8080/servlet/你的servlet的名字
这样你就可以直接访问这个servlet了!
2.使用jcreator进行servlet的程序编写时,需要导入tomcat下,common/lib/servlet.jar
才能调用servlet包
3.测试程序,还是从最简单的Hello,World!来进行练习吧!
代码:
import javax.servlet.*;
import java.io.*;
public class HelloServlet extends GenericServlet
{
//需要重载初象类service
public void service(ServletRequest request,ServletResponse response) throws IOExcetpion
{
PrintWriter out = response.getWriter();
out.println("Hello,this is our world!");
}
}
4.HttpServlet继承了GenericServlet,HttpServletRequest/HttpServletResponse继承ServletRequest/ServletResponse
方法getHeader是得到表头信息
request.getHeader(“connection“) 得到连接信息
request.getHeader(“User-Agent“) 得到用户信息

例子:
import javax.servlet.*;
import java.io.*;
import javax.servlet.http.*; //必须导入这个包,才能使用HttpServlet
public class HelloServlet extends HttpServlet
{
//需要重载初象类service
public void service(HttpServletRequest request,HttpServletResponse response) throws IOExcetpion
{
PrintWriter out = response.getWriter();
String s = request.getHeader("Connection");
String user = request.getHeader("User-Agent");
out.println("you connect to server is"+s);
out.close();
}
}
5.response.setContentType("text/html;charset=gb2312")