(一)DAO设计及BaseDAO和BookDAO的实现

1.总体架构

MVC 设计模式：
Model：POJO（Plain Old Java Object）
Controller：Servlet
View：JSP + EL + JSTL

2.技术选型

数据库：MySQL
数据源：C3P0
JDBC 工具：DBUtils
事务解决方案：Filter + ThreadLocal
Ajax 解决方案：jQuery + JavaScript + JSON + google-gson
层之间解耦方案：工厂设计模式

3.数据表设计

相关表的创建

DROP TABLE IF EXISTS `account`;

CREATE TABLE `account` (
  `accountid` INT(11) NOT NULL AUTO_INCREMENT,
  `balance` FLOAT DEFAULT NULL,
  PRIMARY KEY  (`accountid`)
)
INSERT  INTO `account`(`accountid`,`balance`) VALUES (1,9740);

DROP TABLE IF EXISTS `mybooks`;
CREATE TABLE `mybooks` (
  `Id` INT(11) NOT NULL AUTO_INCREMENT,
  `Author` VARCHAR(30) NOT NULL,
  `Title` VARCHAR(30) NOT NULL,
  `Price` FLOAT NOT NULL,
  `Publishingdate` DATE NOT NULL,
  `Salesamount` INT(11) NOT NULL,
  `Storenumber` INT(11) NOT NULL,
  `Remark` TEXT NOT NULL,
  PRIMARY KEY  (`Id`)
)
INSERT  INTO `mybooks`(`Id`,`Author`,`Title`,`Price`,`Publishingdate`,`Salesamount`,`Storenumber`,`Remark`)
VALUES (1,'Tom','Java 编程思想',50,'2009-06-22',17,83,'Good Java Book'),
(2,'Jerry','Oracle DBA 教材',60,'2009-06-22',12,88,'Good Oracle Book'),
(3,'Bob','Ruby',50,'2009-06-22',12,88,'Good 0'),
(4,'Mike','Javascript',51,'2009-06-22',0,100,'Good 1'),
(5,'Rose','Ajax',52,'2009-06-22',0,100,'Good 2'),
(6,'Backham','Struts',53,'2009-06-22',0,100,'Good 3'),
(7,'Zidon','Hibernate',54,'2009-06-22',2,12,'Good 4'),
(8,'Ronaerdo','Spring',55,'2009-06-22',2,13,'Good 5'),
(9,'Clinsman','Cvs',56,'2009-06-22',0,16,'Good 6'),
(10,'Kaka','Seo',57,'2009-06-22',0,17,'Good 7'),
(11,'Lauer','Lucence',58,'2009-06-22',0,18,'Good 8'),
(12,'Kasi','Guice',59,'2009-06-22',0,19,'Good 9'),
(13,'Prierlo','Mysql',60,'2009-06-22',6,14,'Good 10'),
(14,'Haohaidong','DB2',61,'2009-06-22',9,12,'Good 11'),
(15,'Feige','Sybase',62,'2009-06-22',8,14,'Good 12'),
(16,'Tuoleisi','DBDesign',63,'2009-06-22',0,23,'Good 13'),
(17,'Jielade','Eclipse',64,'2009-06-22',0,24,'Good 14'),
(18,'Teli','Netbeans',65,'2009-06-22',0,25,'Good 15'),
(19,'Lapade','C#',66,'2009-06-22',0,26,'Good 16'),
(20,'Runi','JDBC',67,'2009-06-22',0,27,'Good 17'),
(21,'JoeKeer','Php',68,'2009-06-22',0,28,'Good 18'),
(22,'Jordan','MysqlFront',69,'2009-06-22',5,24,'Good 19'),
(23,'Yaoming','NoteBook',70,'2009-06-22',5,25,'Good 20'),
(24,'Yi','C',71,'2009-06-22',5,26,'Good 21'),
(25,'Sun','Css',72,'2009-06-22',0,32,'Good 22'),
(26,'Xuliang','JQuery',73,'2009-06-22',0,33,'Good 23'),
(27,'Meixi','Ext',74,'2009-06-22',0,34,'Good 24'),
(28,'Apple','iphone',75,'2009-06-22',0,35,'Good 25'),
(29,'Aigo','dc',76,'2009-06-22',0,36,'Good 26'),
(30,'Sony','psp',77,'2009-06-22',0,100,'Good 27'),
(31,'IRiver','mp3',78,'2009-06-22',0,100,'Good 28'),
(32,'Sansing','TV',79,'2009-06-22',0,100,'Good 29');

DROP TABLE IF EXISTS `trade`;
CREATE TABLE `trade` (
  `tradeid` INT(11) NOT NULL AUTO_INCREMENT,
  `userid` INT(11) NOT NULL,
  `tradetime` DATETIME NOT NULL,
  PRIMARY KEY  (`tradeid`),
  KEY `user_id_fk` (`userid`),
  CONSTRAINT `user_id_fk` FOREIGN KEY (`userid`) REFERENCES `userinfo` (`userid`)
)
INSERT  INTO `trade`(`tradeid`,`userid`,`tradetime`) VALUES (12,1,'2012-11-01 00:00:00'),(13,1,'2012-11-01 00:00:00'),
(14,1,'2012-11-01 00:00:00')
,(15,1,'2012-12-20 00:00:00'),
(16,1,'2012-12-20 00:00:00');

DROP TABLE IF EXISTS `tradeitem`;
CREATE TABLE `tradeitem` (
  `itemid` INT(11) NOT NULL AUTO_INCREMENT,
  `bookid` INT(11) DEFAULT NULL,
  `quantity` INT(11) DEFAULT NULL,
  `tradeid` INT(11) DEFAULT NULL,
  PRIMARY KEY  (`itemid`),
  KEY `book_id_fk` (`bookid`),
  KEY `trade_id_fk` (`tradeid`),
  CONSTRAINT `book_id_fk` FOREIGN KEY (`bookid`) REFERENCES `mybooks` (`Id`),
  CONSTRAINT `trade_id_fk` FOREIGN KEY (`tradeid`) REFERENCES `trade` (`tradeid`)
)
INSERT  INTO `tradeitem`(`itemid`,`bookid`,`quantity`,`tradeid`) VALUES (22,1,10,12),
(23,2,10,12),(24,3,10,12),(25,1,1,13),(26,13,2,13),(27,14,3,13),(28,15,4,13),(29,1,1,14),
(30,13,2,14),(31,14,3,14),(32,15,4,14),(33,22,5,14),(34,23,5,14),(35,24,5,14),(36,2,1,15),
(37,1,2,15),(38,3,1,15),(39,2,1,16),(40,1,3,16),(41,3,1,16);

DROP TABLE IF EXISTS `userinfo`;
CREATE TABLE `userinfo` (
  `userid` INT(11) NOT NULL AUTO_INCREMENT,
  `username` VARCHAR(50) DEFAULT NULL,
  `accountid` INT(11) DEFAULT NULL,
  PRIMARY KEY  (`userid`),
  KEY `account_id_fk` (`accountid`),
  CONSTRAINT `account_id_fk` FOREIGN KEY (`accountid`) REFERENCES `account` (`accountid`)
)
INSERT  INTO `userinfo`(`userid`,`username`,`accountid`) VALUES (1,'Tom',1),(2,'AAA',1),(3,'BB',1),(4,'CC',1),(5,'DD',1),(6,'EE',1);

4.搭建环境

加入 C3P0 数据源

--加入 jar 包
     --加入配置文件
     --编辑配置文件

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>

    <named-config name="javawebapp">
        <!--提供获取连接的四个基本信息 -->
        <!--连接本地主机的话： jbdc:mysql://localhost:3306/test 可写成jbdc:mysql:///test -->
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/bookstore</property>
        <property name="user">root</property>
        <property name="password">123456</property>

        <!-- 对数据库连接池管理的基本信息 -->
        <!-- 当数据库连接池中的连接数不够时，c3p0一次向数据库服务器申请的连接数 -->
        <property name="acquireIncrement">5</property>
        <!-- 初始化时的连接数 -->
        <property name="initialPoolSize">10</property>
        <!-- 维护的最少连接数 -->
        <property name="minPoolSize">10</property>
        <!-- 维护的最多的连接数 -->
        <property name="maxPoolSize">100</property>
        <!-- 最多维护的Satement的个数 -->
        <property name="maxStatements">50</property>
        <!-- 每个连接最多使用Statement的个数 -->
        <property name="maxStatementsPerConnection">2</property>

    </named-config>
</c3p0-config>
    

加入 dbutils 工具类
加入 JSTL
其它：使用随时加入

5.Dao 层设计

目录结构

Dao.java

package com.aff.bookstore.dao;

import java.util.List;

/**
 * Dao 接口, 定义 Dao 的基本操作, 由 BaseDao 提供实现.
 * @param <T>: Dao 实际操作的泛型类型
 */
public interface Dao<T> {

    /**
     * 执行 INSERT 操作, 返回插入后的记录的 ID
     * @param sql: 待执行的 SQL 语句
     * @param args: 填充占位符的可变参数
     * @return: 插入新记录的 id
     */
    long insert(String sql, Object ... args);

    /**
     * 执行 UPDATE 操作, 包括 INSERT(但没有返回值), UPDATE, DELETE
     * @param sql: 待执行的 SQL 语句
     * @param args: 填充占位符的可变参数
     */
    void update(String sql, Object ... args);

    /**
     * 执行单条记录的查询操作, 返回与记录对应的类的一个对象
     * @param sql: 待执行的 SQL 语句
     * @param args: 填充占位符的可变参数
     * @return: 与记录对应的类的一个对象
     */
    T query(String sql, Object ... args);

    /**
     * 执行多条记录的查询操作, 返回与记录对应的类的一个 List
     * @param sql: 待执行的 SQL 语句
     * @param args: 填充占位符的可变参数
     * @return: 与记录对应的类的一个 List
     */
    List<T> queryForList(String sql, Object ... args);

    /**
     * 执行一个属性或值的查询操作, 例如查询某一条记录的一个字段, 或查询某个统计信息, 返回要查询的值
     * @param sql: 待执行的 SQL 语句
     * @param args: 填充占位符的可变参数
     * @return: 执行一个属性或值的查询操作, 例如查询某一条记录的一个字段, 或查询某个统计信息, 返回要查询的值
     */
    <V> V getSingleVal(String sql, Object ... args);

    /**
     * 执行批量更新操作
     * @param sql: 待执行的 SQL 语句
     * @param args: 填充占位符的可变参数
     */
    void batch(String sql, Object[]... params);
}

BookDAO.java

package com.aff.bookstore.dao;

import java.util.Collection;
import java.util.List;

import com.aff.bookstore.domain.Book;
import com.aff.bookstore.domain.ShoppingCartItem;
import com.aff.bookstore.web.CriteriaBook;
import com.aff.bookstore.web.Page;

public interface BookDAO {

    /**
     * 根据 id 获取指定 Book 对象
     * @param id
     * @return
     */
    public abstract Book getBook(int id);

    /**
     * 根据传入的 CriteriaBook 对象返回对应的 Page 对象
     * @param cb
     * @return
     */
    public abstract Page<Book> getPage(CriteriaBook cb);

    /**
     * 根据传入的 CriteriaBook 对象返回其对应的记录数
     * @param cb
     * @return
     */
    public abstract long getTotalBookNumber(CriteriaBook cb);

    /**
     * 根据传入的 CriteriaBook 和 pageSize 返回当前页对应的 List
     * @param cb
     * @param pageNo
     * @param pageSize
     * @return
     */
    public abstract List<Book> getPageList(CriteriaBook cb,int pageSize);

    /**
     * 返回指定 id 的 book 的 storeNumber 字段的值
     * @param id
     * @return
     */
    public abstract int getStoreNumber(Integer id);

    /**
     * 根据传入的 ShoppingCartItem 的集合,
     * 批量更新 books 数据表的 storenumber 和 salesnumber 字段的值
     * @param items
     */
    public abstract void batchUpdateStoreNumberAndSalesAmount(
            Collection<ShoppingCartItem> items);

}

BaseDAO.java

package com.aff.bookstore.dao.impl;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.List;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;

import com.aff.bookstore.dao.Dao;
import com.aff.bookstore.db.JDBCUtils;
import com.aff.bookstore.utils.ReflectionUtils;

public class BaseDAO<T> implements Dao<T> {
    private QueryRunner queryRunner = new QueryRunner();
    private Class<T> clazz;

    public BaseDAO() {
        clazz = ReflectionUtils.getSuperGenericType(getClass());

    }

    @Override
    public long insert(String sql, Object... args) {
        // 我们需要返回它的主键id值
        // update 中的insert 操作没有返回值
        // quertRunner也没有返回值
        // 此时需要使用原生的jdbc写
        long id = 0;
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;

        try {
            connection = JDBCUtils.getConnection();
            preparedStatement = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);

            if (args != null) {
                for (int i = 0; i < args.length; i++) {
                    preparedStatement.setObject(i + 1, args[i]);
                }
            }
            preparedStatement.executeUpdate();

            // 获取生成的主键值
            resultSet = preparedStatement.getGeneratedKeys();
            if (resultSet.next()) {
                id = resultSet.getLong(1);// 第一列主键值 id
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.release(resultSet, preparedStatement);
            JDBCUtils.release(connection);
        }
        return id;
    }

    @Override
    public void update(String sql, Object... args) {
        Connection connection = null;

        try {
            connection = JDBCUtils.getConnection();
            queryRunner.update(connection, sql,args);

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.release(connection);
        }
    }

    @Override
    public T query(String sql, Object... args) {
        Connection connection = null;

        try {
            connection = JDBCUtils.getConnection();
            return queryRunner.query(connection, sql, new BeanHandler<>(clazz), args);

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.release(connection);
        }
        return null;
    }

    @Override
    public List<T> queryForList(String sql, Object... args) {
        Connection connection = null;

        try {
            connection = JDBCUtils.getConnection();
            return queryRunner.query(connection, sql, new BeanListHandler<>(clazz), args);

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.release(connection);
        }
        return null;
    }

    @Override
    public <V> V getSingleVal(String sql, Object... args) {
        Connection connection = null;

        try {
            connection = JDBCUtils.getConnection();
            return (V) queryRunner.query(connection, sql, new ScalarHandler(), args);

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.release(connection);
        }
        return null;
    }

    @Override
    public void batch(String sql, Object[]... params) {
        Connection connection = null;

        try {
            connection = JDBCUtils.getConnection();
            queryRunner.batch(connection, sql, params);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.release(connection);
        }
    }
}

BookDaoImpl.java

package com.aff.bookstore.dao.impl;

import java.util.Collection;
import java.util.List;

import com.aff.bookstore.dao.BookDAO;
import com.aff.bookstore.domain.Book;
import com.aff.bookstore.domain.ShoppingCartItem;
import com.aff.bookstore.web.CriteriaBook;
import com.aff.bookstore.web.Page;

public class BookDaoImpl extends BaseDAO<Book> implements BookDAO {

    @Override
    public Book getBook(int id) {
        String sql = "select id,    author, title, price ,publishingDate,salesAmount,storeNumber,remark from mybooks where id = ? ";
        return query(sql, id);
    }

    @Override
    public Page<Book> getPage(CriteriaBook cb) {
        Page page = new Page<>(cb.getPageNo());
        page.setTotalItemNumber(getTotalBookNumber(cb));
        // 检验 pageNo的合法性
        cb.setPageNo(page.getPageNo());

        page.setList(getPageList(cb, 3));
        return page;
    }

    // 获取在这个价格区间的有多少条数目
    @Override
    public long getTotalBookNumber(CriteriaBook cb) {
        String sql = "select count(id) from mybooks where price >=? and price <= ? ";
        return getSingleVal(sql, cb.getMinPrice(), cb.getMaxPrice());
    }

    @Override
    public List<Book> getPageList(CriteriaBook cb, int pageSize) {
        // 起始从0 开始的，所以 (cb.getPageNo()- 1) *pageSize,pageSize
        String sql = "select id,    author, title, price ,publishingDate,salesAmount,storeNumber,remark  from mybooks where price >=? and price <= ?  limit ?,?";
        return queryForList(sql, cb.getMinPrice(), cb.getMaxPrice(), (cb.getPageNo() - 1) * pageSize, pageSize);
    }

    @Override
    public int getStoreNumber(Integer id) {
        String sql = "select storeNumber from mybooks where id = ?";
        return getSingleVal(sql, id);
    }

    @Override
    public void batchUpdateStoreNumberAndSalesAmount(Collection<ShoppingCartItem> items) {

    }
}