基於阿里數據庫連接池Druid和Apache封裝工具類DBUtil的JDBC實現對數據庫視圖的查詢和表的增刪改查操作

1. Druid

Druid首先是一個數據庫連接池。Druid是目前最好的數據庫連接池，在功能、性能、擴展性方面，都超過其他數據庫連接池，包括DBCP、C3P0、BoneCP、Proxool、JBoss DataSource。Druid已經在阿里巴巴部署了超過600個應用，經過一年多生產環境大規模部署的嚴苛考驗。Druid是阿里巴巴開發的號稱爲監控而生的數據庫連接池！
它有三個特點：
- 處理的數據量規模較大。
- 可以進行數據的實時查詢展示。
- 它的查詢模式是交互式的，這也說明其查詢併發能力有限。
Druid 之所以能夠在 OLAP 家族中佔據一席之地，主要依賴其強大的 MPP 架構設計，關於它的架構，這裏就不展開描述了，感興趣的同學可以登陸官網進行了解。

2. Apache工具類DBUtil

具體介紹上面很詳細，也可以看我的代碼。

3.代碼結構

本人的項目並不是在項目的根目錄下面建立的，所以裏面有些路徑是需要修改的。可以把代碼看做參考：

分別代碼：

Test

package com.student.control;

import com.student.dao.sqlstatements.SqlStatement;
import com.student.dao.studao.CRUD_StudentDao;
import com.student.util.DruidConnectionPool;

import java.sql.Connection;
import java.util.List;

public class Test {
//    DruidConnectionPool druidConnectionPool = new DruidConnectionPool();

    public static void main(String[] args) {
        Connection connection = DruidConnectionPool.getConnection();

        CRUD_StudentDao crud_studentDao = new CRUD_StudentDao();
        List list ;
        int rows = 0;

        rows = crud_studentDao.updateTable(SqlStatement.Insert_Check,2017010105,01,"2020-02-18 11:01:54");

        System.out.println("影響了 "+rows+" 行.");

//        2  查詢某個班的 某天的所有考勤信息（查）
//        list = crud_studentDao.selectV_class_check(SqlStatement.Select_Class_Day_All_Check,"計科一班","%2020-02-13%");

//      3   查某個學生 2 月的所有考勤情況（查）
//        list = crud_studentDao.selectV_student_check(SqlStatement.Select_Student_Month_All_Check,"張三","%2020-02%");


//        System.out.println(list);

    }

}

SqlStatement

package com.student.dao.sqlstatements;

//        1  給某個學生記錄 某天的考勤信息（增）
//
//        2  查詢某個班的 某天的所有考勤信息（查）
//
//        3  查某個學生 2 月的所有考勤情況（查）
//

public interface SqlStatement {

//        1  給某個學生記錄 某天的考勤信息（增）
    String Insert_Check = "INSERT INTO checks (s_id,c_id,check_time) VALUES (?,?,?)";


//SELECT * FROM v_class_check WHERE c_name ='計科一班' AND check_time LIKE '%2020-02-17%';
//        2  查詢某個班的 某天的所有考勤信息（查）
    String Select_Class_Day_All_Check = "select * from v_class_check where c_name = ? AND check_time LIKE ?";



//        3  查某個學生 2 月的所有考勤情況（查）
    String Select_Student_Month_All_Check = "SELECT * FROM select_stu_2month WHERE s_name = ? AND check_time LIKE ?";

}

CRUD_StudentDao

package com.student.dao.studao;

import com.student.util.DruidConnectionPool;
import com.student.vo.V_class_check;
import com.student.vo.V_student_check;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;

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

public class CRUD_StudentDao {

    Connection connection = DruidConnectionPool.getConnection();

    int rows = 0;

    List list ;


    /**
     * 根據sql語句，進行對應的表中的字段的更新
     * @param sql
     * 預處理好的PreperedStatement
     * @param args
     * 傳遞的參數值，不過是以數組的另一種寫法
     * @return
     */
    public int updateTable(String sql,Object ...args){
        try {
            QueryRunner queryRunner = new QueryRunner();
            rows = queryRunner.update(connection,sql,args);

            System.out.println("affacts "+rows+" rows.");

            connection.close();

        } catch (SQLException e) {
            e.printStackTrace();
        }

        return rows;
    }



    /**
     * 查詢某個班的 某天的所有考勤信息（查）
     * 根據sql語句進行表查詢，並返回結果集
     * @param sql
     * @param args
     * @return
     */
    public List selectV_class_check(String sql,String ...args){

        try {
            QueryRunner queryRunner = new QueryRunner();

            list = queryRunner.query(connection,sql,new BeanListHandler<V_class_check>(V_class_check.class),args);

            connection.close();

        }catch (Exception e){
            e.printStackTrace();
        }

        return list;
    }



    /**
     * 查某個學生 2 月的所有考勤情況（查）
     * @param sql
     * @param args
     * @return
     */
    public List selectV_student_check (String sql,String ...args){

        try {
            QueryRunner queryRunner = new QueryRunner();

            list = queryRunner.query(connection,sql,new BeanListHandler<V_student_check>(V_student_check.class),args);

            connection.close();

        }catch (Exception e){
            e.printStackTrace();
        }

        return list;
    }



}

DruidConnectionPool

package com.student.util;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.Connection;
import java.util.Properties;

public class DruidConnectionPool {
    static Connection connection;
   public static Connection getConnection() {
       try {
           FileInputStream fileInputStream = new FileInputStream("./src/com/student/druid.properties");
           Properties properties = new Properties();
           properties.load(fileInputStream);

           DataSource dataSource = DruidDataSourceFactory.createDataSource(properties);
            connection= dataSource.getConnection();

           System.out.println(connection);


       } catch (Exception e) {
           e.printStackTrace();
       }
        return connection;
   }

}

V_class_check

package com.student.vo;

import java.sql.Timestamp;

public class V_class_check {
    private int c_id,s_id;
    private String c_name,s_name;
    private Timestamp check_time;


    public V_class_check() {

    }

    public V_class_check(int c_id, int s_id, String c_name, String s_name, Timestamp check_time) {
        this.c_id = c_id;
        this.s_id = s_id;
        this.c_name = c_name;
        this.s_name = s_name;
        this.check_time = check_time;
    }

    public int getC_id() {
        return c_id;
    }

    public void setC_id(int c_id) {
        this.c_id = c_id;
    }

    public int getS_id() {
        return s_id;
    }

    public void setS_id(int s_id) {
        this.s_id = s_id;
    }

    public String getC_name() {
        return c_name;
    }

    public void setC_name(String c_name) {
        this.c_name = c_name;
    }

    public String getS_name() {
        return s_name;
    }

    public void setS_name(String s_name) {
        this.s_name = s_name;
    }

    public Timestamp getCheck_time() {
        return check_time;
    }

    public void setCheck_time(Timestamp check_time) {
        this.check_time = check_time;
    }


    @Override
    public String toString() {
        return "V_class_check{" +
                "c_id=" + c_id +
                ", s_id=" + s_id +
                ", c_name='" + c_name + '\'' +
                ", s_name='" + s_name + '\'' +
                ", check_time=" + check_time +
                '}';
    }
}

V_student_check


package com.student.vo;

import java.sql.Timestamp;

public class V_student_check {
    private int s_id;
    private String s_name,c_name;
    private Timestamp check_time;

    public V_student_check() {

    }

    public V_student_check(int s_id, String s_name, String c_name, Timestamp check_time) {
        this.s_id = s_id;
        this.s_name = s_name;
        this.c_name = c_name;
        this.check_time = check_time;
    }

    public int getS_id() {
        return s_id;
    }

    public void setS_id(int s_id) {
        this.s_id = s_id;
    }

    public String getS_name() {
        return s_name;
    }

    public void setS_name(String s_name) {
        this.s_name = s_name;
    }

    public String getC_name() {
        return c_name;
    }

    public void setC_name(String c_name) {
        this.c_name = c_name;
    }

    public Timestamp getCheck_time() {
        return check_time;
    }

    public void setCheck_time(Timestamp check_time) {
        this.check_time = check_time;
    }

    @Override
    public String toString() {
        return "V_student_check{" +
                "s_id=" + s_id +
                ", s_name='" + s_name + '\'' +
                ", c_name='" + c_name + '\'' +
                ", check_time=" + check_time +
                '}';
    }
}

druid.properties

driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/student_check?characterEncoding=utf8&useSSL=false
username=root
password=Admin888.
#初始連接數
initialSize=5
#最大連接數
maxActive=10
#最大等待時間
maxWait=3000
#最大空閒數
# maxIdle=8
#最小空閒數
# minIdle=3


#下面的代碼用來解決一個報錯的，說是Spingboot配置什麼的，但是目前並沒有進行那麼複雜的操作。所以等以後再來看具體的原因

# com.alibaba.druid.pool.DruidDataSource error
# 嚴重: testWhileIdle is true, validationQuery not set

timeBetweenEvictionRunsMillis=60000
minEvictableIdleTimeMillis=300000
validationQuery=SELECT 1
testWhileIdle=true
testOnBorrow=false
testOnReturn=false
poolPreparedStatements=false
maxPoolPreparedStatementPerConnectionSize=200

#   validationQuery = "SELECT 1"  驗證連接是否可用，使用的SQL語句

#   testWhileIdle = "true"      指明連接是否被空閒連接回收器(如果有)進行檢驗.如果檢測失敗,則連接將被從池中去除.

#   testOnBorrow = "false"   借出連接時不要測試，否則很影響性能

#   timeBetweenEvictionRunsMillis = "30000"  每30秒運行一次空閒連接回收器

#   minEvictableIdleTimeMillis = "1800000"  池中的連接空閒30分鐘後被回收,默認值就是30分鐘。

#   numTestsPerEvictionRun="3" 在每次空閒連接回收器線程(如果有)運行時檢查的連接數量，默認值就是3.

4. SQL腳本和數據庫結構


/*
 Navicat Premium Data Transfer

 Source Server         : 本地連接
 Source Server Type    : MySQL
 Source Server Version : 80019
 Source Host           : localhost:3306
 Source Schema         : student_check

 Target Server Type    : MySQL
 Target Server Version : 80019
 File Encoding         : 65001

 Date: 18/02/2020 19:34:33
*/

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for checks
-- ----------------------------
DROP TABLE IF EXISTS `checks`;
CREATE TABLE `checks` (
  `chno` int NOT NULL AUTO_INCREMENT,
  `s_id` int NOT NULL,
  `c_id` int NOT NULL,
  `check_time` datetime DEFAULT NULL,
  PRIMARY KEY (`chno`,`s_id`,`c_id`),
  UNIQUE KEY `uq_chno` (`chno`) USING BTREE,
  KEY `fk_checks_students_1` (`s_id`),
  KEY `fk_checks_classes_1` (`c_id`),
  CONSTRAINT `fk_checks_classes_1` FOREIGN KEY (`c_id`) REFERENCES `classes` (`c_id`),
  CONSTRAINT `fk_checks_students_1` FOREIGN KEY (`s_id`) REFERENCES `students` (`s_id`)
) ENGINE=InnoDB AUTO_INCREMENT=21 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

-- ----------------------------
-- Records of checks
-- ----------------------------
BEGIN;
INSERT INTO `checks` VALUES (1, 2017010101, 1, '2020-02-10 11:01:54');
INSERT INTO `checks` VALUES (2, 2017010101, 1, '2020-02-11 11:02:18');
INSERT INTO `checks` VALUES (3, 2017010101, 1, '2020-02-12 11:02:34');
INSERT INTO `checks` VALUES (4, 2017010101, 1, '2020-02-13 11:02:52');
INSERT INTO `checks` VALUES (5, 2017010102, 1, '2020-02-10 11:03:14');
INSERT INTO `checks` VALUES (6, 2017010102, 1, '2020-02-11 11:03:27');
INSERT INTO `checks` VALUES (7, 2017010102, 1, '2020-02-12 11:03:39');
INSERT INTO `checks` VALUES (8, 2017010102, 1, '2020-02-13 11:03:51');
INSERT INTO `checks` VALUES (9, 2017010103, 1, '2020-02-10 11:04:02');
INSERT INTO `checks` VALUES (10, 2017010103, 1, '2020-02-11 11:04:15');
INSERT INTO `checks` VALUES (11, 2017010103, 1, '2020-02-12 11:04:26');
INSERT INTO `checks` VALUES (12, 2017010103, 1, '2020-02-13 11:04:45');
INSERT INTO `checks` VALUES (13, 2017010104, 1, '2020-02-10 11:04:56');
INSERT INTO `checks` VALUES (14, 2017010104, 1, '2020-02-11 11:05:05');
INSERT INTO `checks` VALUES (15, 2017010104, 1, '2020-02-12 11:05:15');
INSERT INTO `checks` VALUES (16, 2017010104, 1, '2020-02-13 11:05:24');
INSERT INTO `checks` VALUES (17, 2017010101, 1, '2020-02-17 11:45:53');
INSERT INTO `checks` VALUES (18, 2017010101, 1, '2020-01-22 11:01:54');
INSERT INTO `checks` VALUES (19, 2017010101, 1, '2020-02-18 11:01:54');
COMMIT;

-- ----------------------------
-- Table structure for classes
-- ----------------------------
DROP TABLE IF EXISTS `classes`;
CREATE TABLE `classes` (
  `c_id` int NOT NULL AUTO_INCREMENT,
  `t_id` int DEFAULT NULL,
  `c_name` varchar(25) COLLATE utf8_bin DEFAULT NULL,
  PRIMARY KEY (`c_id`),
  KEY `fk_classes_teachers_1` (`t_id`),
  CONSTRAINT `fk_classes_teachers_1` FOREIGN KEY (`t_id`) REFERENCES `teachers` (`t_id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

-- ----------------------------
-- Records of classes
-- ----------------------------
BEGIN;
INSERT INTO `classes` VALUES (1, 1, '計科一班');
INSERT INTO `classes` VALUES (2, 2, '醫信班');
INSERT INTO `classes` VALUES (3, 3, '信管班');
INSERT INTO `classes` VALUES (4, 4, '計科二班');
COMMIT;

-- ----------------------------
-- Table structure for sdept
-- ----------------------------
DROP TABLE IF EXISTS `sdept`;
CREATE TABLE `sdept` (
  `sdept_id` int NOT NULL AUTO_INCREMENT,
  `sdept_name` varchar(30) COLLATE utf8_bin DEFAULT NULL,
  `sdept_loc` varchar(100) COLLATE utf8_bin DEFAULT NULL,
  `sdept_tel` varchar(11) COLLATE utf8_bin DEFAULT NULL,
  PRIMARY KEY (`sdept_id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

-- ----------------------------
-- Records of sdept
-- ----------------------------
BEGIN;
INSERT INTO `sdept` VALUES (1, '信息科學與工程學院', '三教三樓', '88485568');
INSERT INTO `sdept` VALUES (2, '人文與管理學院', '三教五樓', '88485567');
COMMIT;

-- ----------------------------
-- Table structure for sdept_class
-- ----------------------------
DROP TABLE IF EXISTS `sdept_class`;
CREATE TABLE `sdept_class` (
  `sdc_id` int NOT NULL AUTO_INCREMENT,
  `sdept_id` int DEFAULT NULL,
  `c_id` int DEFAULT NULL,
  PRIMARY KEY (`sdc_id`),
  KEY `fk_sdept_class_sdept_1` (`sdept_id`),
  KEY `fk_sdept_class_classes_1` (`c_id`),
  CONSTRAINT `fk_sdept_class_classes_1` FOREIGN KEY (`c_id`) REFERENCES `classes` (`c_id`),
  CONSTRAINT `fk_sdept_class_sdept_1` FOREIGN KEY (`sdept_id`) REFERENCES `sdept` (`sdept_id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

-- ----------------------------
-- Records of sdept_class
-- ----------------------------
BEGIN;
INSERT INTO `sdept_class` VALUES (1, 1, 1);
INSERT INTO `sdept_class` VALUES (2, 1, 2);
INSERT INTO `sdept_class` VALUES (3, 1, 3);
INSERT INTO `sdept_class` VALUES (4, 1, 4);
COMMIT;

-- ----------------------------
-- Table structure for select_stu_2month
-- ----------------------------
DROP TABLE IF EXISTS `select_stu_2month`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `select_stu_2month` AS select `students`.`s_id` AS `s_id`,`students`.`s_name` AS `s_name`,`c`.`c_name` AS `c_name`,`checks`.`check_time` AS `check_time` from (((`students` join `stu_class` `sc` on((`students`.`s_id` = `sc`.`s_id`))) join `classes` `c` on((`sc`.`c_id` = `c`.`c_id`))) join `checks` on(((`checks`.`s_id` = `students`.`s_id`) and (`checks`.`c_id` = `c`.`c_id`))));

-- ----------------------------
-- Records of select_stu_2month
-- ----------------------------
BEGIN;
INSERT INTO `select_stu_2month` VALUES (2017010101, '張三', '計科一班', '2020-02-10 11:01:54');
INSERT INTO `select_stu_2month` VALUES (2017010101, '張三', '計科一班', '2020-02-11 11:02:18');
INSERT INTO `select_stu_2month` VALUES (2017010101, '張三', '計科一班', '2020-02-12 11:02:34');
INSERT INTO `select_stu_2month` VALUES (2017010101, '張三', '計科一班', '2020-02-13 11:02:52');
INSERT INTO `select_stu_2month` VALUES (2017010101, '張三', '計科一班', '2020-02-17 11:45:53');
INSERT INTO `select_stu_2month` VALUES (2017010101, '張三', '計科一班', '2020-01-22 11:01:54');
INSERT INTO `select_stu_2month` VALUES (2017010101, '張三', '計科一班', '2020-02-18 11:01:54');
INSERT INTO `select_stu_2month` VALUES (2017010102, '李四', '計科一班', '2020-02-10 11:03:14');
INSERT INTO `select_stu_2month` VALUES (2017010102, '李四', '計科一班', '2020-02-11 11:03:27');
INSERT INTO `select_stu_2month` VALUES (2017010102, '李四', '計科一班', '2020-02-12 11:03:39');
INSERT INTO `select_stu_2month` VALUES (2017010102, '李四', '計科一班', '2020-02-13 11:03:51');
INSERT INTO `select_stu_2month` VALUES (2017010103, '王五', '計科一班', '2020-02-10 11:04:02');
INSERT INTO `select_stu_2month` VALUES (2017010103, '王五', '計科一班', '2020-02-11 11:04:15');
INSERT INTO `select_stu_2month` VALUES (2017010103, '王五', '計科一班', '2020-02-12 11:04:26');
INSERT INTO `select_stu_2month` VALUES (2017010103, '王五', '計科一班', '2020-02-13 11:04:45');
INSERT INTO `select_stu_2month` VALUES (2017010104, '趙柳', '計科一班', '2020-02-10 11:04:56');
INSERT INTO `select_stu_2month` VALUES (2017010104, '趙柳', '計科一班', '2020-02-11 11:05:05');
INSERT INTO `select_stu_2month` VALUES (2017010104, '趙柳', '計科一班', '2020-02-12 11:05:15');
INSERT INTO `select_stu_2month` VALUES (2017010104, '趙柳', '計科一班', '2020-02-13 11:05:24');
COMMIT;

-- ----------------------------
-- Table structure for stu_class
-- ----------------------------
DROP TABLE IF EXISTS `stu_class`;
CREATE TABLE `stu_class` (
  `sc_id` int NOT NULL AUTO_INCREMENT,
  `s_id` int DEFAULT NULL,
  `c_id` int DEFAULT NULL,
  PRIMARY KEY (`sc_id`),
  KEY `fk_stu_class_students_1` (`s_id`),
  KEY `fk_stu_class_classes_1` (`c_id`),
  CONSTRAINT `fk_stu_class_classes_1` FOREIGN KEY (`c_id`) REFERENCES `classes` (`c_id`),
  CONSTRAINT `fk_stu_class_students_1` FOREIGN KEY (`s_id`) REFERENCES `students` (`s_id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

-- ----------------------------
-- Records of stu_class
-- ----------------------------
BEGIN;
INSERT INTO `stu_class` VALUES (1, 2017010101, 1);
INSERT INTO `stu_class` VALUES (2, 2017010102, 1);
INSERT INTO `stu_class` VALUES (3, 2017010103, 1);
INSERT INTO `stu_class` VALUES (4, 2017010104, 1);
COMMIT;

-- ----------------------------
-- Table structure for stu_class_sdept
-- ----------------------------
DROP TABLE IF EXISTS `stu_class_sdept`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `stu_class_sdept` AS select `students`.`s_id` AS `學號`,`students`.`s_name` AS `姓名`,`c`.`c_name` AS `班級`,`sdept`.`sdept_name` AS `院系` from ((((`students` join `stu_class` `sc` on((`students`.`s_id` = `sc`.`s_id`))) join `classes` `c` on((`c`.`c_id` = `sc`.`c_id`))) join `sdept_class` on((`sdept_class`.`c_id` = `c`.`c_id`))) join `sdept` on((`sdept`.`sdept_id` = `sdept_class`.`sdept_id`)));

-- ----------------------------
-- Records of stu_class_sdept
-- ----------------------------
BEGIN;
INSERT INTO `stu_class_sdept` VALUES (2017010101, '張三', '計科一班', '信息科學與工程學院');
INSERT INTO `stu_class_sdept` VALUES (2017010102, '李四', '計科一班', '信息科學與工程學院');
INSERT INTO `stu_class_sdept` VALUES (2017010103, '王五', '計科一班', '信息科學與工程學院');
INSERT INTO `stu_class_sdept` VALUES (2017010104, '趙柳', '計科一班', '信息科學與工程學院');
COMMIT;

-- ----------------------------
-- Table structure for stu_class_sdept_check
-- ----------------------------
DROP TABLE IF EXISTS `stu_class_sdept_check`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `stu_class_sdept_check` AS select `students`.`s_id` AS `學號`,`students`.`s_name` AS `姓名`,`c`.`c_name` AS `班級`,`sdept`.`sdept_name` AS `院系`,`checks`.`check_time` AS `打卡時間` from (((((`students` join `stu_class` `sc` on((`students`.`s_id` = `sc`.`s_id`))) join `classes` `c` on((`c`.`c_id` = `sc`.`c_id`))) join `sdept_class` on((`sdept_class`.`c_id` = `c`.`c_id`))) join `sdept` on((`sdept`.`sdept_id` = `sdept_class`.`sdept_id`))) join `checks` on(((`students`.`s_id` = `checks`.`s_id`) and (`c`.`c_id` = `checks`.`c_id`))));

-- ----------------------------
-- Records of stu_class_sdept_check
-- ----------------------------
BEGIN;
INSERT INTO `stu_class_sdept_check` VALUES (2017010101, '張三', '計科一班', '信息科學與工程學院', '2020-02-10 11:01:54');
INSERT INTO `stu_class_sdept_check` VALUES (2017010101, '張三', '計科一班', '信息科學與工程學院', '2020-02-11 11:02:18');
INSERT INTO `stu_class_sdept_check` VALUES (2017010101, '張三', '計科一班', '信息科學與工程學院', '2020-02-12 11:02:34');
INSERT INTO `stu_class_sdept_check` VALUES (2017010101, '張三', '計科一班', '信息科學與工程學院', '2020-02-13 11:02:52');
INSERT INTO `stu_class_sdept_check` VALUES (2017010101, '張三', '計科一班', '信息科學與工程學院', '2020-02-17 11:45:53');
INSERT INTO `stu_class_sdept_check` VALUES (2017010101, '張三', '計科一班', '信息科學與工程學院', '2020-01-22 11:01:54');
INSERT INTO `stu_class_sdept_check` VALUES (2017010101, '張三', '計科一班', '信息科學與工程學院', '2020-02-18 11:01:54');
INSERT INTO `stu_class_sdept_check` VALUES (2017010102, '李四', '計科一班', '信息科學與工程學院', '2020-02-10 11:03:14');
INSERT INTO `stu_class_sdept_check` VALUES (2017010102, '李四', '計科一班', '信息科學與工程學院', '2020-02-11 11:03:27');
INSERT INTO `stu_class_sdept_check` VALUES (2017010102, '李四', '計科一班', '信息科學與工程學院', '2020-02-12 11:03:39');
INSERT INTO `stu_class_sdept_check` VALUES (2017010102, '李四', '計科一班', '信息科學與工程學院', '2020-02-13 11:03:51');
INSERT INTO `stu_class_sdept_check` VALUES (2017010103, '王五', '計科一班', '信息科學與工程學院', '2020-02-10 11:04:02');
INSERT INTO `stu_class_sdept_check` VALUES (2017010103, '王五', '計科一班', '信息科學與工程學院', '2020-02-11 11:04:15');
INSERT INTO `stu_class_sdept_check` VALUES (2017010103, '王五', '計科一班', '信息科學與工程學院', '2020-02-12 11:04:26');
INSERT INTO `stu_class_sdept_check` VALUES (2017010103, '王五', '計科一班', '信息科學與工程學院', '2020-02-13 11:04:45');
INSERT INTO `stu_class_sdept_check` VALUES (2017010104, '趙柳', '計科一班', '信息科學與工程學院', '2020-02-10 11:04:56');
INSERT INTO `stu_class_sdept_check` VALUES (2017010104, '趙柳', '計科一班', '信息科學與工程學院', '2020-02-11 11:05:05');
INSERT INTO `stu_class_sdept_check` VALUES (2017010104, '趙柳', '計科一班', '信息科學與工程學院', '2020-02-12 11:05:15');
INSERT INTO `stu_class_sdept_check` VALUES (2017010104, '趙柳', '計科一班', '信息科學與工程學院', '2020-02-13 11:05:24');
COMMIT;

-- ----------------------------
-- Table structure for students
-- ----------------------------
DROP TABLE IF EXISTS `students`;
CREATE TABLE `students` (
  `s_id` int NOT NULL AUTO_INCREMENT,
  `s_name` varchar(20) COLLATE utf8_bin DEFAULT NULL,
  `s_sex` varchar(5) COLLATE utf8_bin DEFAULT NULL,
  `s_grade` int DEFAULT NULL,
  `s_loc` varchar(255) COLLATE utf8_bin DEFAULT NULL,
  PRIMARY KEY (`s_id`)
) ENGINE=InnoDB AUTO_INCREMENT=2017010105 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

-- ----------------------------
-- Records of students
-- ----------------------------
BEGIN;
INSERT INTO `students` VALUES (2017010101, '張三', '男', 2017, '湖南長沙');
INSERT INTO `students` VALUES (2017010102, '李四', '男', 2017, '湖南常德');
INSERT INTO `students` VALUES (2017010103, '王五', '女', 2017, '湖南嶽陽');
INSERT INTO `students` VALUES (2017010104, '趙柳', '女', 2017, '湖南衡陽');
COMMIT;

-- ----------------------------
-- Table structure for teachers
-- ----------------------------
DROP TABLE IF EXISTS `teachers`;
CREATE TABLE `teachers` (
  `t_id` int NOT NULL AUTO_INCREMENT,
  `t_name` varchar(10) COLLATE utf8_bin DEFAULT NULL,
  `t_tel` varchar(11) COLLATE utf8_bin DEFAULT NULL,
  PRIMARY KEY (`t_id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

-- ----------------------------
-- Records of teachers
-- ----------------------------
BEGIN;
INSERT INTO `teachers` VALUES (1, '王老師', '13107342356');
INSERT INTO `teachers` VALUES (2, '劉老師', '13107314569');
INSERT INTO `teachers` VALUES (3, '羅老師', '12456892356');
INSERT INTO `teachers` VALUES (4, '陳老師', '12545784521');
COMMIT;

-- ----------------------------
-- Table structure for v_class_check
-- ----------------------------
DROP TABLE IF EXISTS `v_class_check`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v_class_check` AS select `c`.`c_id` AS `c_id`,`c`.`c_name` AS `c_name`,`students`.`s_id` AS `s_id`,`students`.`s_name` AS `s_name`,`checks`.`check_time` AS `check_time` from (((`classes` `c` join `stu_class` `sc` on((`sc`.`c_id` = `c`.`c_id`))) join `students` on((`students`.`s_id` = `sc`.`s_id`))) join `checks` on(((`checks`.`c_id` = `c`.`c_id`) and (`checks`.`s_id` = `students`.`s_id`))));

-- ----------------------------
-- Records of v_class_check
-- ----------------------------
BEGIN;
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010101, '張三', '2020-02-10 11:01:54');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010101, '張三', '2020-02-11 11:02:18');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010101, '張三', '2020-02-12 11:02:34');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010101, '張三', '2020-02-13 11:02:52');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010101, '張三', '2020-02-17 11:45:53');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010101, '張三', '2020-01-22 11:01:54');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010101, '張三', '2020-02-18 11:01:54');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010102, '李四', '2020-02-10 11:03:14');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010102, '李四', '2020-02-11 11:03:27');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010102, '李四', '2020-02-12 11:03:39');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010102, '李四', '2020-02-13 11:03:51');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010103, '王五', '2020-02-10 11:04:02');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010103, '王五', '2020-02-11 11:04:15');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010103, '王五', '2020-02-12 11:04:26');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010103, '王五', '2020-02-13 11:04:45');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010104, '趙柳', '2020-02-10 11:04:56');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010104, '趙柳', '2020-02-11 11:05:05');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010104, '趙柳', '2020-02-12 11:05:15');
INSERT INTO `v_class_check` VALUES (1, '計科一班', 2017010104, '趙柳', '2020-02-13 11:05:24');
COMMIT;

-- ----------------------------
-- View structure for select_stu_2month
-- ----------------------------
DROP VIEW IF EXISTS `select_stu_2month`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `select_stu_2month` AS select `students`.`s_id` AS `s_id`,`students`.`s_name` AS `s_name`,`c`.`c_name` AS `c_name`,`checks`.`check_time` AS `check_time` from (((`students` join `stu_class` `sc` on((`students`.`s_id` = `sc`.`s_id`))) join `classes` `c` on((`sc`.`c_id` = `c`.`c_id`))) join `checks` on(((`checks`.`s_id` = `students`.`s_id`) and (`checks`.`c_id` = `c`.`c_id`))));

-- ----------------------------
-- View structure for stu_class_sdept
-- ----------------------------
DROP VIEW IF EXISTS `stu_class_sdept`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `stu_class_sdept` AS select `students`.`s_id` AS `學號`,`students`.`s_name` AS `姓名`,`c`.`c_name` AS `班級`,`sdept`.`sdept_name` AS `院系` from ((((`students` join `stu_class` `sc` on((`students`.`s_id` = `sc`.`s_id`))) join `classes` `c` on((`c`.`c_id` = `sc`.`c_id`))) join `sdept_class` on((`sdept_class`.`c_id` = `c`.`c_id`))) join `sdept` on((`sdept`.`sdept_id` = `sdept_class`.`sdept_id`)));

-- ----------------------------
-- View structure for stu_class_sdept_check
-- ----------------------------
DROP VIEW IF EXISTS `stu_class_sdept_check`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `stu_class_sdept_check` AS select `students`.`s_id` AS `學號`,`students`.`s_name` AS `姓名`,`c`.`c_name` AS `班級`,`sdept`.`sdept_name` AS `院系`,`checks`.`check_time` AS `打卡時間` from (((((`students` join `stu_class` `sc` on((`students`.`s_id` = `sc`.`s_id`))) join `classes` `c` on((`c`.`c_id` = `sc`.`c_id`))) join `sdept_class` on((`sdept_class`.`c_id` = `c`.`c_id`))) join `sdept` on((`sdept`.`sdept_id` = `sdept_class`.`sdept_id`))) join `checks` on(((`students`.`s_id` = `checks`.`s_id`) and (`c`.`c_id` = `checks`.`c_id`))));

-- ----------------------------
-- View structure for v_class_check
-- ----------------------------
DROP VIEW IF EXISTS `v_class_check`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v_class_check` AS select `c`.`c_id` AS `c_id`,`c`.`c_name` AS `c_name`,`students`.`s_id` AS `s_id`,`students`.`s_name` AS `s_name`,`checks`.`check_time` AS `check_time` from (((`classes` `c` join `stu_class` `sc` on((`sc`.`c_id` = `c`.`c_id`))) join `students` on((`students`.`s_id` = `sc`.`s_id`))) join `checks` on(((`checks`.`c_id` = `c`.`c_id`) and (`checks`.`s_id` = `students`.`s_id`))));

SET FOREIGN_KEY_CHECKS = 1;

創建視圖方便查詢：具體代碼可以結合Java項目中DAO包的代碼。

--1  給某個學生記錄 某天的考勤信息（增）
INSERT INTO checks (s_id,c_id,check_time) VALUES (2017010101,01,'2020-01-22 11:01:54');

SELECT CURRENT_TIME();

SELECT NOW();

--2  查詢某個班的 某天的所有考勤信息（查）
SELECT c.c_id,c.c_name,students.s_id,students.s_name,checks.check_time
FROM classes c
INNER JOIN stu_class sc ON sc.c_id = c.c_id
INNER JOIN students ON students.s_id = sc.s_id
INNER JOIN checks on checks.c_id = c.c_id AND checks.s_id = students.s_id
WHERE c.c_name='計科一班' AND checks.check_time LIKE '%2020-02-13%';

CREATE VIEW v_class_check AS
SELECT c.c_id,c.c_name,students.s_id,students.s_name,checks.check_time
FROM classes c
INNER JOIN stu_class sc ON sc.c_id = c.c_id
INNER JOIN students ON students.s_id = sc.s_id
INNER JOIN checks on checks.c_id = c.c_id AND checks.s_id = students.s_id

SELECT * FROM v_class_check WHERE c_name ='計科一班' AND check_time LIKE '%2020-02-17%';


--3  查某個學生 2 月的所有考勤情況（查）
SELECT students.s_id, students.s_name, c.c_name, checks.check_time
FROM students
INNER JOIN stu_class sc ON students.s_id = sc.s_id
INNER JOIN classes c ON sc.c_id = c.c_id
INNER JOIN checks ON checks.s_id = students.s_id AND checks.c_id = c.c_id

CREATE VIEW select_stu_2month AS 
SELECT students.s_id, students.s_name, c.c_name, checks.check_time
FROM students
INNER JOIN stu_class sc ON students.s_id = sc.s_id
INNER JOIN classes c ON sc.c_id = c.c_id
INNER JOIN checks ON checks.s_id = students.s_id AND checks.c_id = c.c_id


SELECT * FROM select_stu_2month WHERE s_name = '張三' AND check_time LIKE '%2020-02%';

SQL表結構

5. 結語

如果讀者有什麼不明白的可以私聊或者評論，看到了都會耐心仔細回覆。
學而不思則罔，思而不學則殆。共勉！

具體項目代碼可以移步我的碼雲

基於阿里數據庫連接池Druid和Apache封裝工具類DBUtil的JDBC實現對數據庫視圖的查詢和表的增刪改查操作

1. Druid

2. Apache工具類DBUtil

3.代碼結構

4. SQL腳本和數據庫結構

5. 結語

Mybatis 環境搭建並簡單測試

解決Tuxera試用過期重裝問題

try、catch、finally中的return由誰決定

Servlet重定向和請求轉發的區別

Mac下ssh報錯，清除原有密鑰

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

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