目录一、前言二、案例需求三、开始第一步四、第二步五、第三步六、第四步七、总结
一、前言
二、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数据库中的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，欢迎你
5.登录失败跳转到FailServlet展示：登录失败密码错误
三、开始第一步
首先创建项目，写html页面，配置文件，jar包
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Title</title></head><body><form action="/day14/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>
druid.properties配置文件：
driverClassName=com.mysql.cj.jdbc.Driverurl=jdbc:mysql:///day14username=rootpassword=root#初始化连接数量initialSize=5#最大连接数maxActive=10#最大等待时间maxWait=3000filters=stattimeBetweenEvictionRunsMillis=60000minEvictableIdleTimeMillis=300000validationQuery=SELECT 1testWhileIdle=truetestOnBorrow=falsetestOnReturn=falsepoolPreparedStatements=falsemaxPoolPreparedStatementPerConnectionSize=200
导入jar包：
四、第二步
创建user类：
package com.wzc.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 + ''' + '}'; }}
五、第三步
创建jdbcUtils工具类
package com.wzc.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;//JDBC工具类 使用Druid连接池public class JDBCUtils { private static DataSource ds ; static { try {// 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 is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"); pro.load(is);// 初始化连接池对象 ds = DruidDataSourceFactory.createDataSource(pro); } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); }// 初始化连接池 } /*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(); }}
创建UserDao类，提供login方法：
package com.wzc.dao;import com.wzc.domain.User;import com.wzc.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 user包含用户全部数据,没有查询到则返回null */ public User login(User loginUser){ try{ // 编写sql String sql = "select * from user where username = ? and password = ?";// 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();// 记录日志 return null; } }}
编写loginServlet类：
package com.wzc.web.servlet;import com.wzc.dao.UserDao;import com.wzc.domain.User;import org.apache.commons.beanutils.BeanUtils;import javax.servlet.ServletContext;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 { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 设置编码 req.setCharacterEncoding("utf-8");/*// 获取请求参数 String username = req.getParameter("username"); String password = req.getParameter("password");// 封装user对象 User loginUser = new User(); loginUser.setUsername(username); loginUser.setPassword(password);*/// 获取所有请求参数 Map<String,String[]> map = req.getParameterMap();// 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(); }// 调用UserDao的login方法 UserDao dao = new UserDao(); User user = dao.login(loginUser);// 判断user if (user == null){// 登录失败 req.getRequestDispatcher("/failServlet").forward(req,resp); }else{// 登录成功// 存储数据 req.setAttribute("user",user);// 转发 req.getRequestDispatcher("/successServlet").forward(req,resp); } } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doGet(req,resp); }}
六、第四步
编写SuccessServlet类：
package com.wzc.web.servlet;import com.wzc.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(name = "/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()+",欢迎你"); } } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request,response); }}
编写FailServelt类
package com.wzc.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，用户名和密码错误"); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request,response); }}
输入错误的账号和密码
登录失败提示：
七、总结
login.html中form表单的action路径写法：虚拟路径+Servlet的资源路径
**BeanUtils工具类，简化数据封装：**用于封装javaBean
javaBean：标准的java类 功能：封装数据
有一下四点要求：
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
属性：setter和getter方法截取后的产物例如：getUsername()–>Username–>username可见username就是属性方法有三种：
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（最常用）
package com.wzc.test;import com.wzc.domain.User;import org.apache.commons.beanutils.BeanUtils;import org.junit.Test;import java.lang.reflect.InvocationTargetException;public class BeanUtilsTest { @Test public void test(){ User user = new User(); try { BeanUtils.setProperty(user,"hehe","male"); System.out.println(user); String gender = BeanUtils.getProperty(user, "hehe"); System.out.println(gender); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } catch (NoSuchMethodException e) { e.printStackTrace(); } }}
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