Servlet基础

Servlet基础

Servlet基础学习文档地址：https://pan.baidu.com/s/10hQtJ8b5SPPenEBzZ6A47w 提取码：54lt

1：Servlet的生命周期

代码:

@WebServlet("/serverss")
public class serverss implements Servlet{
    

	@Override//更新代码或者关闭服务器才会销毁
	public void destroy() {
    
		// TODO Auto-generated method stub
		System.out.println("销毁了");
		
	}

	@Override//得到配置
	public ServletConfig getServletConfig() {
    
		// TODO Auto-generated method stub
		return null;
	}

	@Override//得到消息
	public String getServletInfo() {
    
		// TODO Auto-generated method stub
		return null;
	}

	@Override//一进入就初始化
	public void init(ServletConfig arg0) throws ServletException {
    
		// TODO Auto-generated method stub
		System.out.println("初始化了");
	}

	@Override
	public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {
    
		// TODO Auto-generated method stub
		//服务
		request.setCharacterEncoding("utf-8");
		response.setCharacterEncoding("utf-8");
		
		
	}

}

2：Servlet的生命周期的各个阶段:

ServeltConfig接口
在Servlet初始化过程中获取配置信息
一个Servlet只有一个ServletConfig对象

ServeltConfig接口的常用方法

@WebServlet("/CHeck")
public class CHeck extends HttpServlet {
    
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
		//调用dopost
		doPost(request, response);
	}

	/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
		//设置编码
		request.setCharacterEncoding("utf-8");
		response.setCharacterEncoding("utf-8");
		//获取username
		String uname=request.getParameter("uname");
		//调用biz层 根据用户名查找数据库是否存在这个用户
		String name="admin";
		String result="";
		if(uname.equals(name)) {
    
			result="该用户已存在";
		}else {
    
			result="可以注册";
		}
		//响应给用户
				PrintWriter out=response.getWriter();
				out.println(result);
		
	}

}

ServeltConText接口
获取Servlet上下文

ServeltConText接口的常用方法

GenericServlet抽象类
提供了Servlet与ServletConfig接口的默认实现方法

GenericServlet的常用方法

HttpServlet继承于GenericServlet
处理HTTP协议的请求和响应

HttpServlet的方法

那我们如何在项目中部署呢？
如下图：