03_用servlet、request和Druid技术写登录案例
用户登录案例需求：
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
1.编写login.html登录页面
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>登录页面</title> </head> <body> <form action="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>
2.使用Druid数据库连接池技术,操作mysql
2.1添加lib包，在包中放入相应的Jar包，将lib包add as Library,在src文件下创建druid.properties文件
driverClassName=com.mysql.cj.jdbc.Driver url=jdbc:mysql://localhost:3306/test02?useUnicode=true&characterEncoding=utf-8&userSSL=false&serverTimezone=GMT%2B8 username=root password=123456 initialSize=5 maxActive=10 maxWait=3000 filters=stat timeBetweenEvictionRunsMillis=60000 minEvictableIdleTimeMillis=300000 validationQuery=SELECT 1 testWhileIdle=true testOnBorrow=false testOnReturn=false poolPreparedStatements=false maxPoolPreparedStatementPerConnectionSize=200
注意：url连接后设置数据库时区、编码方式等。
2.2创建JDBCUtil.java
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 JDBCUtil { private static DataSource ds; static { try { //1.加载配置文件 Properties pro = new Properties(); //使用ClassLoader加载配置文件，获取字节输入流 InputStream resourceAsStream = JDBCUtil.class.getClassLoader().getResourceAsStream("druid.properties"); pro.load(resourceAsStream); //2.初始化连接池对象 ds = DruidDataSourceFactory.createDataSource(pro); } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } public static DataSource getDataSource(){ return ds; } public static Connection GetConnection() throws SQLException { return ds.getConnection(); } }
3创建User实例
public class User { private String name; private String password; public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } @Override public String toString() { return "User{" + "name='" + name + '\'' + ", password='" + password + '\'' + '}'; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
4创建UserDao方法
import cn.hubu.domain.User; import cn.hubu.util.JDBCUtil; import org.springframework.dao.DataAccessException; import org.springframework.jdbc.core.BeanPropertyRowMapper; import org.springframework.jdbc.core.JdbcTemplate; //操作数据库的User类 public class UserDao { //声明JDBCTemplate对象共用 private JdbcTemplate template = new JdbcTemplate(JDBCUtil.getDataSource()); /* * 登录方法 * loginUser只有用户名和密码 * user包含用户全部数据，没有查询到，返回null * */ public User login(User loginUser){ try { //编写sql String sql="select * from user where name=? and password=?"; //调用query方法 User user =template.queryForObject( sql, new BeanPropertyRowMapper<User>(User.class), loginUser.getName(), loginUser.getPassword() ); return user; } catch (DataAccessException e) { e.printStackTrace(); return null; } } }
5建立UserDao测试类，UserDaoTest.java
import cn.hubu.dao.UserDao; import cn.hubu.domain.User; import org.junit.Test; public class UserDaoTest { @Test public void TestLogin(){ User loginuser = new User(); loginuser.setName("2019"); loginuser.setPassword("1234"); UserDao dao = new UserDao(); User user = dao.login(loginuser); System.out.println(user); } }
6 创建loginServlet.java文件。
获取参数map集合,将map集合注入loginUser类中
import cn.hubu.dao.UserDao; import cn.hubu.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 request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request,response); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1.设置编码 request.setCharacterEncoding("utf-8"); // //2.获取请求参数 // String username = request.getParameter("username"); // String password = request.getParameter("password"); Map<String, String[]> map = request.getParameterMap(); //3.封装User对象 User loginUser =new User(); // loginUser.setName(username); ////// loginUser.setPassword(password); try { BeanUtils.populate(loginUser,map); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } //4.调用UserDao中Login方法 UserDao dao = new UserDao(); User user = dao.login(loginUser); //5.判断user if(user==null){ //登录失败 request.getRequestDispatcher("/failServlet").forward(request,response); }else{ //登录成功 //存储数据 request.setAttribute("user",user); //转发 request.getRequestDispatcher("/successServlet").forward(request,response); } } }
7 创建登录失败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 { this.doGet(request,response); } protected void doGet(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！"); } }
8 创建登录成功servlet
import cn.hubu.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 { this.doGet(request,response); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取request中的user对象 User user =(User) request.getAttribute("user"); // if(user!=null){ //设置编码格式 response.setContentType("text/html;charset=utf-8"); //输出 response.getWriter().write("登录成功！"+user.getName()+"欢迎你"); } } }
9.项目包全局图
