- druid是一个非常常用的数据库连接池,可以和jdbc template一起来使用
- 下面我们就模拟一个登录的场景
数据库建设
- 创建一个login数据库,并且创建一个user表包含id,username,password三个字段。
- 并且默认一个数据,做好数据准备工作
项目搭建
- 在IDEA中创建一个login模块,并在src目录中创建我们要用到的包
- 在包domain存放我们的用户类User对应数据库user表,设置成员变量一一对应user数据库表
package cn.wang.domain;
public class User {
private int id;
private String username;
private String password;
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + 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;
}
}
- 数据库连接池配置,在web文件夹下新建WEB-INF文件夹,把需要的jar包放到lib文件夹下,并加载到模块中
- 在src文件夹下存放druid配置文件 druid.properties文件,配置数据库信息
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///login
username=root
password=
initialSize=5
maxActive=10
maxWait=3000
- 在util包中新建JDBCUtils数据库连接工具类
package cn.wang.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;
/**
* Durid连接池使用
*/
public class JDBCUtils {
private static DataSource ds;
static {
try {
Properties pro = new Properties();
InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
pro.load(is);
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;
}
/**
* 获取连接对象
*/
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
}
- 在包dao中新建UserDao对数据库进行操作,返回User对象
package cn.wang.dao;
import cn.wang.domain.User;
import cn.wang.util.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
public class UserDao {
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
public User login(User loginUser) {
try {
String sql = "select * from user where username = ? and password = ?";
User user = template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), loginUser.getUsername(), loginUser.getPassword());
return user;
} catch (DataAccessException e) {
e.printStackTrace();
return null;
}
}
}
- 创建Test测试数据连接是否正确,在包test中创建UserDaoTest,并且进行执行,执行成功则我们的连接正常
package cn.wang.test;
import cn.wang.dao.UserDao;
import cn.wang.domain.User;
import org.junit.Test;
public class UserDaoTest {
@Test
public void testLogin() {
User loginuser = new User();
loginuser.setUsername("admin");
loginuser.setPassword("123456");
UserDao dao = new UserDao();
User user = dao.login(loginuser);
System.out.println(user);
}
}
-
上面我们的内部处理已经完成,后面我们只需要将,web提交的数据进行上面流程并且进行登录判断,在新建servlet进行数据接受并调用上述的过程
-
在web目录下新建login.html文件,用于数据提交
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</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>
- 在servlet包中创建LoginServlet用于接受表单数据
package cn.wang.web.servlet;
import cn.wang.dao.UserDao;
import cn.wang.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("/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 {
request.setCharacterEncoding("utf-8");
System.out.println("doget");
String username = request.getParameter("username");
String password = request.getParameter("password");
User loginUser = new User();
loginUser.setUsername(username);
loginUser.setPassword(password);
UserDao dao = new UserDao();
User user = dao.login(loginUser);
if (user == null) {
request.getRequestDispatcher("/failServlet").forward(request, response);
} else {
request.setAttribute("user", user);
request.getRequestDispatcher("/successServlet").forward(request, response);
}
}
}
-
接收到表单的数据,执行dao中的逻辑,并在servlet中进行结果判断,有结果转到成功servlet处理,失败则转到另一个进行处理
-
失败
package cn.wang.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 {
response.setContentType("text/html;charset=utf-8");
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);
}
}
- 成功
package cn.wang.web.servlet;
import cn.wang.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 {
User user = (User) request.getAttribute("user");
if (user != null) {
response.setContentType("text/html;charset=utf-8");
response.getWriter().write("登陆成功!"+user.getUsername()+",欢迎你");
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}