Servlet 高级获取初始化参数 & MVC设计模块 & Model1,Model2两种模型简介

获取初始化参数

在这里插入图片描述在web.xml中使用init-param初始化参数

<servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>GetInitParameterServlet</servlet-name>
    <servlet-class>servlet.GetInitParameterServlet</servlet-class>
    
    <init-param>
      <param-name>username</param-name>
      <param-value>admin</param-value>
    </init-param>
    <init-param>
      <param-name>password</param-name>
      <param-value>123456</param-value>
    </init-param>
    
  </servlet>
  <servlet-mapping>
    <servlet-name>GetInitParameterServlet</servlet-name>
    <url-pattern>/servlet/GetInitParameterServlet</url-pattern>
  </servlet-mapping>

创建servlet名字为：GetInitParameterServlet
首先在GetInitParameterServlet界面设置变量用来在后面接受从web.xml初始化的值

	private String username;//用户名
	private String password;//密码
	
	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

this.getInitParameter("username")方法获取web.xml初始化的值
this.setUsername(this.getInitParameter(“username”));
在servlet页面获取初始化的值

public void init() throws ServletException {
		this.setUsername(this.getInitParameter("username"));
		this.setPassword(this.getInitParameter("password"));

将获取的值输出

public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html; charset=utf-8");
		PrintWriter out = response.getWriter();
		out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
		out.println("<HTML>");
		out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
		out.println("  <BODY>");
		out.print("<h2>"+"用户名:"+this.getUsername()+"</h2>");
		out.print("<h2>"+"密码:"+this.getPassword()+"</h2>");
		out.println("  </BODY>");
		out.println("</HTML>");
		out.flush();
		out.close();
	}