综合案例(Servlet + JDBC)

综合案例(Servlet JDBC)

• 要求：实现登录功能、展示所有用户功能
• 以下仅展示关键代码

1.数据库

代码语言：javascript复制

CREATE TABLE admin(
  username VARCHAR(20) PRIMARY KEY,
  PASSWORD VARCHAR(20) NOT NULL,
  phone varchar(11) NOT NULL,
  Address varchar(20) NOT NULL
)CHARSET=utf8;

INSERT INTO admin(username,PASSWORD,phone,address)
VALUES('gavin','123456','12345678901','北京市昌平区');
INSERT INTO admin(username,PASSWORD,phone,address)
VALUES('aaron','123456','12345678901','北京市昌平区');

2.DBUtils

代码语言：javascript复制

package com.qf.servletProject.utils;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidDataSourceFactory;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

public class DbUtils {
    private static DruidDataSource ds;
    private static final ThreadLocal<Connection> THREAD_LOCAL = new ThreadLocal<>();

    static {
        Properties properties = new Properties();
        InputStream inputStream = DbUtils.class.getResourceAsStream("/database.properties");
        try {
            properties.load(inputStream);
            ds = (DruidDataSource) DruidDataSourceFactory.createDataSource(properties);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static Connection getConnection() {
        Connection connection = THREAD_LOCAL.get();
        try {
            if (connection == null) {
                connection = ds.getConnection();
                THREAD_LOCAL.set(connection);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return connection;
    }

    public static void begin() {
        Connection connection = null;
        try {
            connection = getConnection();
            connection.setAutoCommit(false);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void commit() {
        Connection connection = null;
        try {
            connection = getConnection();
            connection.commit();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeAll(connection, null, null);
        }
    }

    public static void rollback() {
        Connection connection = null;
        try {
            connection = getConnection();
            connection.rollback();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeAll(connection, null, null);
        }
    }

    public static void closeAll(Connection connection, Statement statement, ResultSet resultSet) {
        try {
            if (resultSet != null) {
                resultSet.close();
            }
            if (statement != null) {
                statement.close();
            }
            if (connection != null) {
                connection.close();
                THREAD_LOCAL.remove();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

3.AdminDaoImpl

代码语言：javascript复制

package com.qf.servletProject.dao.impl;

import com.qf.servletProject.dao.AdminDao;
import com.qf.servletProject.entity.Admin;
import com.qf.servletProject.utils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import java.sql.SQLException;
import java.util.List;

public class AdminDaoImpl implements AdminDao {
    private QueryRunner queryRunner = new QueryRunner();
    @Override
    public int insert(Admin admin) {
        return 0;
    }

    @Override
    public int delete(String username) {
        return 0;
    }

    @Override
    public int update(Admin admin) {
        return 0;
    }

    @Override
    public Admin select(String username) {
        try {
            Admin admin = queryRunner.query(DbUtils.getConnection(),"select * from admin where username=?;",new BeanHandler<Admin>(Admin.class),username);
            return admin;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    public List<Admin> selectAll() {
        try {
            List<Admin> admins = queryRunner.query(DbUtils.getConnection(),"select * from admin",new BeanListHandler<Admin>(Admin.class));
            return admins;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }
}

4.AdminServiceImpl

代码语言：javascript复制

package com.qf.servletProject.service.impl;

import com.qf.servletProject.dao.AdminDao;
import com.qf.servletProject.dao.impl.AdminDaoImpl;
import com.qf.servletProject.entity.Admin;
import com.qf.servletProject.service.AdminService;
import com.qf.servletProject.utils.DbUtils;

import java.util.List;

public class AdminServiceImpl implements AdminService {
    private AdminDao adminDao = new AdminDaoImpl();
    @Override
    public Admin login(String username, String password) {
        Admin result = null;
        try {
            DbUtils.begin();
            Admin admin = adminDao.select(username);
            if(admin!=null){
                if(admin.getPassword().equals(password)){
                    result = admin;
                }
            }
            DbUtils.commit();
        } catch (Exception e) {
            DbUtils.rollback();
            e.printStackTrace();
        }
        return result;
    }

    @Override
    public List<Admin> showAllAdmin() {
        List<Admin> admins = null;
        try {
            DbUtils.begin();
            admins = adminDao.selectAll();
            DbUtils.commit();
        } catch (Exception e) {
            DbUtils.rollback();
            e.printStackTrace();
        }

        return admins;
    }
}

5.HTML页面代码

代码语言：javascript复制

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录页面</title>
</head>
<body>
    <form action="/WebProject_war_exploded/login" 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>

6.LoginServlet

代码语言：javascript复制

package com.qf.servletProject.servlet;

import com.qf.servletProject.entity.Admin;
import com.qf.servletProject.service.AdminService;
import com.qf.servletProject.service.impl.AdminServiceImpl;

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.io.PrintWriter;

@WebServlet(value = "/login")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        resp.setContentType("text/html;charset=UTF-8");
        //1.收参
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        //2.调用业务逻辑
        AdminService adminService = new AdminServiceImpl();
        Admin admin = adminService.login(username,password);
        //3.处理结果
        PrintWriter printWriter = resp.getWriter();
        if(admin!=null){
            //响应给客户端一个结果页面，显示登录成功
            printWriter.println("<html>");
            printWriter.println("<head>");
            printWriter.println("<meta charset='UTF-8'>");
            printWriter.println("<title>结果页面</title>");
            printWriter.println("</head>");
            printWriter.println("<body>");
            printWriter.println("<h1>登录成功！</h1>");
            printWriter.println("</body>");
            printWriter.println("</html>");
        }else{
            //响应给客户端一个结果页面，显示登录失败！
            printWriter.println("<html>");
            printWriter.println("<head>");
            printWriter.println("<meta charset='UTF-8'>");
            printWriter.println("<title>结果页面</title>");
            printWriter.println("</head>");
            printWriter.println("<body>");
            printWriter.println("<h1>登录失败！</h1>");
            printWriter.println("</body>");
            printWriter.println("</html>");
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req,resp);
    }
}

7.ShowAllAdminServlet

代码语言：javascript复制

package com.qf.servletProject.servlet;

import com.qf.servletProject.entity.Admin;
import com.qf.servletProject.service.AdminService;
import com.qf.servletProject.service.impl.AdminServiceImpl;

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.io.PrintWriter;
import java.util.List;

@WebServlet(value = "/showall")
public class ShowAllAdminServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        AdminService adminService = new AdminServiceImpl();

        List<Admin> adminList = adminService.showAllAdmin();

        PrintWriter printWriter = resp.getWriter();

        if(adminList!=null){
            printWriter.println("<html>");
            printWriter.println("<head>");
            printWriter.println("<meta charset='UTF-8'>");
            printWriter.println("<title>显示所有</title>");
            printWriter.println("</head>");
            printWriter.println("<body>");
            printWriter.println("<table border='1'>");
            printWriter.println("   <tr>");
            printWriter.println("       <td>username</td>");
            printWriter.println("       <td>password</td>");
            printWriter.println("       <td>phone</td>");
            printWriter.println("       <td>address</td>");
            printWriter.println("   </tr>");
            for(Admin admin : adminList){
                printWriter.println("   <tr>");
                printWriter.println("       <td>" admin.getUsername() "</td>");
                printWriter.println("       <td>" admin.getPassword() "</td>");
                printWriter.println("       <td>" admin.getPhone() "</td>");
                printWriter.println("       <td>" admin.getAddress() "</td>");
                printWriter.println("   </tr>");
            }
            printWriter.println("</table>");
            printWriter.println("</body>");
            printWriter.println("</html>");
        }else{
            printWriter.println("<html>");
            printWriter.println("<head>");
            printWriter.println("<meta charset='UTF-8'>");
            printWriter.println("<title>显示所有</title>");
            printWriter.println("</head>");
            printWriter.println("<body>");
            printWriter.println("<h3>当前没有用户！</h3>");
            printWriter.println("</body>");
            printWriter.println("</html>");
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req,resp);
    }
}

七、 转发与重定向

servlet java

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