request登录案例
一、案例需求
1.编写login.html登录页面 username & password 两个输入框 2.使用Druid数据库连接池技术,操作mysql，day14数据库中user表 3.使用JdbcTemplate技术封装JDBC 4.登录成功跳转到SuccessServlet展示：登录成功！用户名,欢迎您 5.登录失败跳转到FailServlet展示：登录失败，用户名或密码错误
login.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <form action="/day14_test/loginServlet" method="post"> 用户名:<input type="text" name="username"> <br> 密码:<input type="password" name="password"><br> <input type="submit" value="登录"> </form> </body> </html>
二、开发步骤
1. 创建项目，导入html页面，配置文件，jar包
2. 创建数据库环境
CREATE DATABASE day14; USE day14; CREATE TABLE USER( id INT PRIMARY KEY AUTO_INCREMENT, username VARCHAR(32) UNIQUE NOT NULL, PASSWORD VARCHAR(32) NOT NULL );
3. 创建包cn.itcast.domain, 创建类User
package cn.itcast.domain; /** * 用户的实体类 */ public class User { private int id; private String username; private String password; public int getId() { return id; } public void setId(int id) { this.id = id; } 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; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + '\'' + ", password='" + password + '\'' + '}'; } }
4、4. 创建包cn.itcast.util,编写工具类JDBCUtils
package cn.itcast.util; import com.alibaba.druid.pool.DruidDataSourceFactory; import javax.sql.DataSource; import java.io.IOException; import java.io.InputStream; import java.sql.Connection; import java.sql.SQLException; import java.util.Properties; public class JDBCUtils { private static DataSource ds; static { try { //1.加载配置文件 Properties pro = new Properties(); InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"); pro.load(is); //2.初始化连接池对象 ds = DruidDataSourceFactory.createDataSource(pro); } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } /** * 获取连接池对象 */ public static DataSource getDataSource() { return ds; } /** * 获取连接connection对象 */ public static Connection getConnection() throws SQLException { return ds.getConnection(); } }
5. 创建包cn.itcast.dao,创建类UserDao,提供login方法
package cn.itcast.dao; import cn.itcast.domain.User; import cn.itcast.util.JDBCUtils; import org.springframework.dao.DataAccessException; import org.springframework.jdbc.core.BeanPropertyRowMapper; import org.springframework.jdbc.core.JdbcTemplate; /** * 操作数据库中User表的类 */ public class UserDao { //声明JDBCTemplate来对象共用 private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource()); /** * 登录方法 * @param loginUser 只有用户名和密码 * @return 包含用户全部数据 */ public User login(User loginUser) { try { //1.编写SQL String sql = "select * from user where username = ? and password = ?"; //2.调用query方法 User user = template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), loginUser.getUsername(), loginUser.getPassword()); return user; } catch (DataAccessException e) { e.printStackTrace(); return null; } } }
6. 编写cn.itcast.web.servlet.LoginServlet类
package cn.itcast.web.servlet; import cn.itcast.dao.UserDao; import cn.itcast.domain.User; import org.apache.commons.beanutils.BeanUtils; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.util.Map; @WebServlet("/loginServlet") public class LoginServlet extends HttpServlet { protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //1.设置编码 req.setCharacterEncoding("utf-8"); /* //2.获取请求参数 String username = req.getParameter("username"); String password = req.getParameter("password"); //3.封装user对象 User loginUser = new User(); loginUser.setUsername(username); loginUser.setPassword(password); */ //2.获取所有请求参数 Map<String, String[]> map = req.getParameterMap(); //3.创建user对象 User loginUser = new User(); //使用BeanUtils封装 try { BeanUtils.populate(loginUser,map); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } //4.调用UserDao的login方法 UserDao dao = new UserDao(); User user = dao.login(loginUser); //5.判断user if(user == null) { //登录失败 req.getRequestDispatcher("/failServlet").forward(req,resp); }else { //登陆成功 //存储数据 req.setAttribute("user",user); //转发 req.getRequestDispatcher("/successServlet").forward(req,resp); } } protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req,resp); } }
7. 编写FailServlet和SuccessServlet类
----------------------------- package cn.itcast.web.servlet; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet("/failServlet") public class FailServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //给页面写一句话 //设置编码 response.setContentType("text/html;charset=utf-8"); //输出 response.getWriter().write("登录失败，用户名或密码错误"); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request,response); } } ----------------------------- package cn.itcast.web.servlet; import cn.itcast.domain.User; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet("/successServlet") public class SuccessServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取request域中共享的user对象 User user = (User) request.getAttribute("user"); if(user != null) { //给页面写一句话 //设置编码 response.setContentType("text/html;charset=utf-8"); //输出 response.getWriter().write("登录成功，"+ user.getUsername()+",欢迎您！"); } } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request,response); } }
8. login.html中form表单的action路径的写法
* 虚拟目录+Servlet的资源路径
* IDEA中tocmat配置了虚拟路径三、BeanUtils工具类
BeanUtils工具类，简化数据封装
* 用于封装JavaBean的
1. JavaBean：标准的Java类
1. 要求：
1. 类必须被public修饰
2. 必须提供空参的构造器
3. 成员变量必须使用private修饰
4. 提供公共setter和getter方法
2. 功能：封装数据
2. 概念：
成员变量：
属性：setter和getter方法截取后的产物
例如：getUsername() --> Username--> username
3. 方法：
1. setProperty()
2. getProperty()
3. populate(Object obj , Map map):将map集合的键值对信息，封装到对应的JavaBean对象中
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