Servlet的温习

Servlet的复习。

温习一下Servlet的应用：

一、Servlet在web.xml中的配置：

  <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>Login</servlet-name>
    <servlet-class>com.servlet.Login</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>Login</servlet-name>
    <url-pattern>/servlet/Login</url-pattern>
  </servlet-mapping>

    注：<url-pattern>的取值很重要，在表单中要用到。

二、Servlet类如下所示：

package com.servlet;

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 Login extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public Login() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
			
		doPost(request,response);
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		String nextPage =  "";
		
		HttpSession session = request.getSession();
		AccountBean account = new AccountBean();
		String userName = request.getParameter("username");
		String pwd = request.getParameter("pwd");
		account.setUsername(userName);
		account.setPassword(pwd);
		
		if(account.getUsername().equals("hongboliu") && account.getPassword().equals("654321")){
			System.out.println();
			session.setAttribute("account", account);
			nextPage = "http://www.google.com.hk";
		}else{
			nextPage = "http://www.baidu.com";
		}
		response.sendRedirect(nextPage);
		
		return ;
		
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occurs
	 */
	public void init() throws ServletException {
		System.out.println("init method");
	}

}

 

三、  AccountBean的设计如下：

package com.servlet;

public class AccountBean {
	private String username;
	private String password;
	
	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;
	}
	
}

 四、Form表单内容如下：

    <form action="servlet/Login" method="post">
    	username：<input type="text" name="username"><br>
    	password：<input type="password" name="pwd"><br>
    	<input type="submit" value=" 确 定 ">
    </form>

    注：form 中action的取值要与web.xml中<url-pattern>的值一致。

五、完成了。