Java（27）：MVC框架基础：Servlet+Jsp+javabean（3）

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日期：2017/11/16

下面通过一个例子来熟悉MVC编程。

代码1 ---- JavaBean：

package srevletTest.test;

public class UserJavaBean {
		private String username;
		private String password;
		public UserJavaBean(){}
		public UserJavaBean(String username,String password){
			this.username = username;
			this.password = password;
		}
		public String getUsername(){
			return this.username;
		}
		public void setUsername(String name){
			this.username = name;
		}		
		public String getPassword(){
			return this.password;
		}
		public void setPassword(String password){
			this.password = password;
		}
				
}

代码2 ---- Servlet：

package srevletTest.test;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class MVCTest extends HttpServlet {
		
	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		System.out.println("doGet()...MVCTest");
		UserJavaBean usb = new UserJavaBean();
		String xm = ""; String ps = ""; 
		xm = request.getParameter("username");
		ps = request.getParameter("password");
		usb.setPassword(ps);
		usb.setUsername(xm);
		HttpSession s = request.getSession(true);
		s.setAttribute("username", usb.getUsername());
//		response.sendRedirect("http:localhost:80\\my\\jsp\\main.jsp");
		response.sendRedirect("jsp\\main.jsp");
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		System.out.println("doPost()...MVCTest");
		doGet(req,resp);
	}
	

}

开启Tomcat后，访问新建的web-app，下面是index.html（默认页面）；

代码3 ---- index.html

<head>
	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<form action="http://localhost/my/MVCTest"    method="get">
        用户名： <input type="text" name="username" size="15" >
         <br><br> 
        密  码:  <input type="password" name="password" size="15" >
        <br><br>
       <input type="submit"  name="submit"  value="登录"><br>
</form>

对于写好的 servlet ，需要在 web.xml 上进行注册，添加以下代码；

代码4 ---- web.xml

    <servlet>
      <servlet-name>MVCTest</servlet-name>
      <servlet-class>srevletTest.test.MVCTest</servlet-class>
    </servlet>
    <servlet-mapping> 
        <servlet-name>MVCTest</servlet-name>
        <url-pattern>/MVCTest</url-pattern>
    </servlet-mapping>

为了降低前后端代码的耦合性，JSP 完成了 servlet 撰写的前端处理，通过使用 response.sendRedirect("jsp\\main.jsp"); 对JSP进行调用。

代码5 ---- main.jsp

<body>
<h1>
<% out.println("this is a test"); %>
<%= session.getAttribute("username")%>,You have signed successfully!
</h1>

</body>

结果显示：