路径记录自imooc:JAVA遇见HTML——Servlet篇 http://www.imooc.com/learn/269
---1-1 Servlet--------------------------------------------------
Servlet：servlet是在服务器上运行的小程序。一个servlet就是一个java小程序，并且可以通过“请求-响应”编程模式来访问这个驻留在服务器内存里的servlet程序。
① Servlet就是JAVA 类
② Servlet是一个继承HttpServlet类的类
③ 这个在服务器端运行，用以处理客户端的请求
---1-2 Tomcat容器等级--------------------------------------------------
Tomcat容器等级分为四个等级
Servlet的容器管理Context容器，一个Context对应一个Web工程。
1.Tomcat 容器
2. Container 容器
3. Engine 引擎容器
4. Host 主机
5. Servlet 容器（tomcat最低级别的容器）里面包含了一个或多个Context
— Context （上下文，背景，环境） 一个Context对应一个Web项目
—— Wrapper 容器里的封装部分
---1-3 手工编写第一个Servlet--------------------------------------------------
1.自己编写的Servlet继承了HttpServlet类,一般只需覆盖doPost或者doGet方法,不必覆盖sevrvice( )方法.
因为一个sevrvice( )方法会调用doPost或者doGet方法
2.HttpServlet类扩展了GenericServlet类,实现了GenericServlet类的抽象方法sevrvice( )
3.HttpServlet类有两个sevrvice( )方法
HelloServlet.java:
response.setContentType("text/html;charset=utf-8");//指定输出文件类型"text/html"，字符集charset为"utf-8"
--------
package servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class HelloServlet extends HttpServlet {
/**
* Constructor of the object.
*/
public HelloServlet() {
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 {
System.out.println("处理Get请求...");
response.setContentType("text/html");
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.println("<strong>Hello Servlet!</strong><br>");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
/**
* 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 {
System.out.println("处理Post请求...");
response.setContentType("text/html;charset=utf-8");//指定输出文件类型"text/html"，字符集charset为"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.println("<strong>Hello Servlet!</strong><br>");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
web.xml:
servlet的URL：localhost是服务器主机名，也可以是IP地址127.0.0.1；8080是tomcat服务器的端口号；
helloapp是web工程的上下文地址ContexRoot（一般情况下与web工程名一致）；最后是<url-pattern/>标签中的内容。
a. <servlet>与<servlet-mapping>的<servlet-name>一一对应
b.<url-pattern>/servlet/HelloServlet</url-pattern> 与JSP中的<a href="servlet/HelloServlet">Get方式请求HelloServlet</a>的URL路径一一对应
/servlet/HelloServlet，"/"项目根目录
<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>HelloServlet</servlet-name>//a
<servlet-class>servlet.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloServlet</servlet-name>//a
<url-pattern>/servlet/HelloServlet</url-pattern>//定义
</servlet-mapping>
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <display-name></display-name> <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>HelloServlet</servlet-name> <servlet-class>servlet.HelloServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>HelloServlet</servlet-name> <url-pattern>/servlet/HelloServlet</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
index.jsp：
1.Get方式请求HelloServlet
<h1>使用MyEclipse创建Servlet小例子</h1>
<hr>
<a href="servlet/HelloServlet">Get方式请求HelloServlet</a><br>
2.Post方式请求HelloServlet 注：编写Servlet的doPost方法时，需要抛出ServletExcpetion和IOException异常
<form action="servlet/HelloServlet" method="post">
<input type="submit" value="Post方式请求HelloServlet"/>
</form>
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'index.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <h1>使用MyEclipse创建Servlet小例子</h1> <hr> <a href="servlet/HelloServlet">Get方式请求HelloServlet</a><br>
<!--Post方式提交--> <form action="servlet/HelloServlet" method="post"> <input type="submit" value="Post方式请求HelloServlet"/> </form> </body> </html>
---1-6 Servlet执行流程和声明周期--------------------------------------------------
Servlet执行流程：此处以get方式举例：请求 -> <servlet-mapping>中的<url-pattern>-> <servlet-name> -> <servlet>中的<servlet-name> -> <servlet-class> ->servlet类中执行doGet()或doPost()。
Get方式请求HelloServlet ---> <a href="servlet/HelloServlet"> 超链接方式为GET方式
通过a(url)找到b(name)，通过b找到c(name)再找到d(class)
如图:
servlet生命周期
servlet的生命周期分为三个阶段：
1.初始化阶段，调用init()方法
2.响应阶段，调用service()方法,决定调用doGet()还是doPost()
3.终止阶段，调用destory()方法
简单的可以概述为：
servlet的生命周期包括的就是初始化，加载，实例化，服务和销毁
---1-9 Tomcat装载Servlet的三种情况--------------------------------------------------
下列时刻Servlet容器装载Servlet：
1.自动加载模式：Servlet容器启动时自动装载某些Servlet，实现它只需要在web.xml文件中<Servlet></Servlet>之间添加 如下代码：
<load-on-startup>1</load-on-startup> 数字越小优先级越高
2.servlet容器启动之后，客户端首次向服务器发出请求时。
3.servlet类文件更新之后，重新装载servlet。
servlet被装载之后servlet容器创建一个servlet实例并且调用servlet的init()方法进行初始化，在servlet的整个生命周期里，init()只被调用一次。
注：server停止时才执行destory()
package servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class TestServlet1 extends HttpServlet { /** * Constructor of the object. */ public TestServlet1() { System.out.println("TestServlet1构造方法被执行...."); } /** * Destruction of the servlet. <br> */ public void destroy() { System.out.println("TestServlet1销毁方法被执行...."); } /** * 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 { System.out.println("TestServlet1的doGet()方法被执行..."); 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.println("<h1>大家好，我是TestServlet1！</h1>"); out.println(" </BODY>"); out.println("</HTML>"); out.flush(); out.close(); } /** * 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 { System.out.println("TestServlet1的doPost()方法被执行..."); doGet(request,response); //让doPost()执行与doGet()相同的操作。 } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException { // Put your code here System.out.println("TestServlet1的初始化方法被执行...."); } }
web.xml:
验证自动装载：load-on-startup的数字越小优先级越高，优先加载
<load-on-startup>2</load-on-startup>
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <display-name></display-name> <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>TestServlet1</servlet-name> <servlet-class>servlet.TestServlet1</servlet-class> <load-on-startup>2</load-on-startup> </servlet> <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>TestServlet2</servlet-name> <servlet-class>servlet.TestServlet2</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>TestServlet1</servlet-name> <url-pattern>/servlet/TestServlet1</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>TestServlet2</servlet-name> <url-pattern>/servlet/TestServlet2</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
---1-10 Servlet与JSP内置对象的对应关系--------------------------------------------------
注：out(type:jspWriter)与resq.getWriter(type:printWriter)实际上类型不一致
---1-11 Servlet获取表单数据--------------------------------------------------
提交表单页reg.jsp：
日期格式(dateFormat)参考-JAVA豆知识
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'reg.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> <style type="text/css"> .label{ width: 20% } .controler{ width: 80% } </style> <script type="text/javascript" src="js/Calendar3.js"></script> </head> <body> <h1>用户注册</h1> <hr> <form name="regForm" action="servlet/RegServlet" method="post" > <table border="0" width="800" cellspacing="0" cellpadding="0"> <tr> <td class="lalel">用户名：</td> <td class="controler"><input type="text" name="username" /></td> </tr> <tr> <td class="label">密码：</td> <td class="controler"><input type="password" name="mypassword" ></td> </tr> <tr> <td class="label">确认密码：</td> <td class="controler"><input type="password" name="confirmpass" ></td> </tr> <tr> <td class="label">电子邮箱：</td> <td class="controler"><input type="text" name="email" ></td> </tr> <tr> <td class="label">性别：</td> <td class="controler"><input type="radio" name="gender" checked="checked" value="Male">男<input type="radio" name="gender" value="Female">女</td> </tr> <tr> <td class="label">出生日期：</td> <td class="controler"> <input name="birthday" type="text" id="control_date" size="10" maxlength="10" onclick="new Calendar().show(this);" readonly="readonly" /> </td> </tr> <tr> <td class="label">爱好：</td> <td class="controler"> <input type="checkbox" name="favorite" value="nba"> NBA <input type="checkbox" name="favorite" value="music"> 音乐 <input type="checkbox" name="favorite" value="movie"> 电影 <input type="checkbox" name="favorite" value="internet"> 上网 </td> </tr> <tr> <td class="label">自我介绍：</td> <td class="controler"> <textarea name="introduce" rows="10" cols="40"></textarea> </td> </tr> <tr> <td class="label">接受协议：</td> <td class="controler"> <input type="checkbox" name="isAccept" value="true">是否接受霸王条款 </td> </tr> <tr> <td colspan="2" align="center"> <input type="submit" value="注册"/> <input type="reset" value="取消"/> </td> </tr> </table> </form> </body> </html>
user.java:
package entity; import java.util.Date; //用户实体类 public class Users { private String username; //用户名 private String mypassword; //密码 private String email; //电子邮箱 private String gender; //性别 private Date birthday; //出生日期 private String[] favorites; //爱好 private String introduce; //自我介绍 private boolean flag; //是否接受协议 public Users() { } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getMypassword() { return mypassword; } public void setMypassword(String mypassword) { this.mypassword = mypassword; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } public String[] getFavorites() { return favorites; } public void setFavorites(String[] favorites) { this.favorites = favorites; } public String getIntroduce() { return introduce; } public void setIntroduce(String introduce) { this.introduce = introduce; } public boolean isFlag() { return flag; } public void setFlag(boolean flag) { this.flag = flag; } }
servlet:
package servlet; import java.io.IOException; import java.io.PrintWriter; import java.text.SimpleDateFormat; import java.util.Date; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import entity.Users; public class RegServlet extends HttpServlet { /** * Constructor of the object. */ public RegServlet() { 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 { request.setCharacterEncoding("utf-8"); Users u = new Users(); String username,mypassword,gender,email,introduce,isAccept; Date birthday; String[] favorites; SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); try { username = request.getParameter("username"); mypassword = request.getParameter("mypassword"); gender = request.getParameter("gender"); email = request.getParameter("email"); introduce = request.getParameter("introduce"); birthday = sdf.parse(request.getParameter("birthday")); if(request.getParameterValues("isAccpet")!=null) { isAccept = request.getParameter("isAccept"); } else { isAccept = "false"; } //用来获取多个复选按钮的值 favorites = request.getParameterValues("favorite"); u.setUsername(username); u.setMypassword(mypassword); u.setGender(gender); u.setEmail(email); u.setFavorites(favorites); u.setIntroduce(introduce); if(isAccept.equals("true")) { u.setFlag(true); } else { u.setFlag(false); } u.setBirthday(birthday); //把注册成功的用户对象保存在session中 request.getSession().setAttribute("regUser", u); //跳转到注册成功页面 request.getRequestDispatcher("../userinfo.jsp").forward(request,response); } catch(Exception ex) { ex.printStackTrace(); } } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException { // Put your code here } }
跳转页面userinfo.jsp
1. Servlet编辑并保存user对象：
//把注册成功的用户对象保存在session中
request.getSession().setAttribute("regUser", u);
//跳转到注册成功页面
request.getRequestDispatcher("../userinfo.jsp").forward(request,response);
2.userInfo.jsp:
通过javabean获取传递的user(modol)
<jsp:useBean id="regUser" class="entity.Users" scope="session"/>
<jsp:getProperty name="regUser" property="gender"/>//property为user的property
<%@ page language="java" import="java.util.*,java.text.*" contentType="text/html; charset=utf-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'userinfo.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> <style type="text/css"> .title{ width: 30%; background-color: #CCC; font-weight: bold; } .content{ width:70%; background-color: #CBCFE5; } </style> </head> <body> <h1>用户信息</h1> <hr> <center> <jsp:useBean id="regUser" class="entity.Users" scope="session"/> <table width="600" cellpadding="0" cellspacing="0" border="1"> <tr> <td class="title">用户名：</td> <td class="content"> <jsp:getProperty name="regUser" property="username"/></td> </tr> <tr> <td class="title">密码：</td> <td class="content"> <jsp:getProperty name="regUser" property="mypassword"/></td> </tr> <tr> <td class="title">性别：</td> <td class="content"> <jsp:getProperty name="regUser" property="gender"/></td> </tr> <tr> <td class="title">E-mail：</td> <td class="content"> <jsp:getProperty name="regUser" property="email"/></td> </tr> <tr> <td class="title">出生日期：</td> <td class="content"> <% SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日"); String date = sdf.format(regUser.getBirthday()); %> <%=date%> </td> </tr> <tr> <td class="title">爱好：</td> <td class="content"> <% String[] favorites = regUser.getFavorites(); for(String f:favorites) { %> <%=f%> <% } %> </td> </tr> <tr> <td class="title">自我介绍：</td> <td class="content"> <jsp:getProperty name="regUser" property="introduce"/></td> </tr> <tr> <td class="title">是否介绍协议：</td> <td class="content"> <jsp:getProperty name="regUser" property="flag"/></td> </tr> </table> </center> </body> </html>
---1-13 Servlet 路径跳转--------------------------------------------------
绝对路径：<a href="<%=path%>/servlet/HelloServlet">访问HelloServlet!</a>
相对路径：<a href="servlet/HelloServlet">访问HelloServlet!</a>
方式1：
<servlet-mapping>
<servlet-name>HelloServlet</servlet-name>
<!--url-pattern处必须以/开头，这里的/表示项目的根目录 -->
<url-pattern>/servlet/HelloServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>TestServlet</servlet-name>
<url-pattern>/servlet/TestServlet</url-pattern>
</servlet-mapping>
方式2：
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'index.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <h1>Servlet路径跳转</h1> <hr> <!--使用相对路径访问HelloServlet --> <!-- /servlet/HelloServlet 第一个/表示服务器的根目录 --> <a href="servlet/HelloServlet">访问HelloServlet!</a><br> <!-- 使用绝对路径 访问HelloServlet,可以使用path变量:path变量表示项目的根目录--> <a href="<%=path%>/servlet/HelloServlet">访问HelloServlet!</a><br> <!--表单中action的URL地址写法，与超链接方式完全相同。 --> <a href="servlet/TestServlet">访问TestServlet,跳转到Test.jsp</a> </body> </html>
请求重定向和服务器内部跳转
//使用request.getContextPath获得上下文对象
response.sendRedirect(request.getContextPath()+"/test.jsp");
方式3：请求重定向
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//请求重定向方式跳转到test.jsp,当前路径是ServletPathDirection/servlet/
//response.sendRedirect("test.jsp");//test.jsp为相对路径
方式4：服务器内部跳转
//test.jsp在根目录下
//服务器内部跳转,这里的斜线表示项目的根目录 。../表示返回当前目录上一级
//request.getRequestDispatcher("/test.jsp").forward(request, response);
request.getRequestDispatcher("../test.jsp").forward(request, response);
}
---1-14 Servlet-阶段案例-------------------------------------------------
package servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.po.Users; public class LoginServlet extends HttpServlet { /** * Constructor of the object. */ public LoginServlet() { 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 { Users u = new Users(); String username = request.getParameter("username"); String password = request.getParameter("password"); u.setUsername(username); u.setPassword(password); //判断用户名和密码是否合法 if(u.getUsername().equals("admin")&&u.getPassword().equals("admin")) { response.sendRedirect(request.getContextPath()+"/login_success.jsp"); } else { response.sendRedirect(request.getContextPath()+"/login_failure.jsp"); } } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException { // Put your code here } }