【JAVA高并发秒杀API之DAO层】课程笔记
2016-06-27 20:07
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最近在慕课网上学习了【JAVA高并发秒杀API】系列课程，在此整理课程内容！
课程收获：1、学习了如何通过maven创建web项目，pom.xml 文件依赖管理。
2、学习如何整合spring+mybatis
3、学习了相关配置文件的书写。
创建完毕，目录结构如下：
相关说明：src/main/java下面放 java代码
src/main/resources下面放 配置文件等。
src/test/是相关 单元测试的文件。
可以新建一个src/test/sql/ 下面存放 创建数据库和表格的SQL源码
首先需要修改web.xml中的servlet版本：
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0"
metadata-complete="true">
<!-- 修改servlet版本 -->
</web-app>
创建完毕之后需要填写pom.xml文件，常用的依赖包已经配置在pom.xml之中，具体如下：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.seckill</groupId>
<artifactId>seckill</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>seckill Maven Webapp</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<!-- 使用junit4 -->
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!-- 补全项目的依赖 -->
<!-- 1:日志 java日志：slf4j, log4j, logback, common-logging
slf4j 是规范/接口
日志实现：log4j, logback, common-logging
使用：slf4j + logback
-->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.12</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.1.2</version>
</dependency>
<!-- 2:数据库相关依赖 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
<scope>runtime</scope>
</dependency>
<!-- 数据库连接池c3p0 -->
<dependency>
<groupId>c3p0</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.1.2</version>
</dependency>
<!-- DAO框架Mybatis依赖 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.8</version>
</dependency>
<!-- Mybatis自身实现的spring整合依赖 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>1.2.3</version>
</dependency>
<!-- 3：servlet web相关依赖 -->
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.7.4</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
<!-- 4：spring依赖 -->
<!-- 1) spring核心 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<!-- 2) spring DAO层依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<!-- 3) spring web相关依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<!-- 4) spring test相关依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
</dependencies>
</project>
至此，一个整合spring+mybatis 的 web项目基本搭建完毕！！
在src/main/resources 下创建mybatis-config.xml 文件（配置mybatis全局属性）
在src/main/resources下新建文件夹spring和mapper：spring下主要存spring相关配置文件，mapper主要存DAO的相关映射。
在src/main/resources/spring/下创建文件spring-dao.xml 文件（配置连接数据库，整合mybatis配置）
jdbc.properties文件内容：（注意变量名必须这样写，不能自定义）
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql://localhost:3306/seckill?useUnicode=true&characterEncoding=utf8
jdbc.user=tao
jdbc.password=password
mybatis-config.xml文件内容：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 配置全局属性 -->
<settings>
<!-- 使用jdbc的getGeneratedKeys获取数据库自增主键值 -->
<setting name="useGeneratedKeys" value="true"/>
<!-- 使用列别名替换列名 默认：true -->
<setting name="useColumnLabel" value="true"/>
<!-- 开启驼峰命名自动转换 -->
<setting name="mapUnderscoreToCamelCase" value="true"/>
</settings>
</configuration>
spring-dao.xml文件内容：（注意：classpath指代的是src/main/java和src/main/resources）
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/2002/xmlspec/dtd/2.10/xmlspec.dtd">
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!-- 配置整合mybatis过程 -->
<!-- 1:配置数据库相关参数 properties的属性：${url} -->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!-- 2:数据库的连接池 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<!-- 配置连接池属性 -->
<property name="driverClass" value="${jdbc.driverClass}"></property>
<property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
<property name="user" value="${jdbc.user}"></property>
<property name="password" value="${jdbc.password}"></property>
<!--连接池中保留的最小连接数。-->
<property name="minPoolSize" value="10"></property>
<!--连接池中保留的最大连接数。Default: 15 -->
<property name="maxPoolSize" value="30"></property>
<!--关闭连接后不自动commit -->
<property name="autoCommitOnClose" value="false"></property>
<!-- 获取连接超时时间 -->
<property name="checkoutTimeout" value="1000"></property>
<!--定义在从数据库获取新连接失败后重复尝试的次数。Default: 30 -->
<property name="acquireRetryAttempts" value="2" />
</bean>
<!-- 3:配置SqlSessionFactory对象 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 注入c3p0数据库连接池 -->
<property name="dataSource" ref="dataSource" />
<!-- 配置mybatis全局配置文件：mybatis-config.xml -->
<property name="configLocation" value="classpath:mybatis-config.xml"></property>
<!-- 扫描entity包，使用别名 -->
<property name="typeAliasesPackage" value="org.seckill.entity"></property>
<!-- 扫描sql配置文件：mapper需要的xml文件 -->
<property name="mapperLocations" value="classpath:mapper/*.xml"></property>
</bean>
<!-- 4:配置扫描Dao接口包，动态实现Dao接口，注入到spring容器中 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!-- 注入sqlSessionFactroy -->
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
<!-- 给出扫描Dao接口包 -->
<property name="basePackage" value="org.seckill.dao" />
</bean>
</beans>
（注意：代码中高亮部分相关文件的位置可以根据具体项目进行填写）
至此，基本配置完毕！
相关SQL语句：schema.sql文件
-- 数据库初始化脚本
-- 创建数据库
CREATE DATABASE seckill;
-- 使用数据库
use seckill;
-- 创建秒杀库存表
CREATE TABLE seckill(
seckill_id bigint NOT NULL AUTO_INCREMENT COMMENT '商品库存id',
name varchar(120) NOT NULL COMMENT '商品名称',
number int NOT NULL COMMENT '库存数量',
create_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
start_time DATETIME NOT NULL COMMENT '秒杀开启时间',
end_time DATETIME NOT NULL COMMENT '秒杀结束时间',
PRIMARY KEY(seckill_id),
key idx_start_time(start_time),
key idx_end_time(end_time),
key idx_create_time(create_time)
)ENGINE=InnoDB AUTO_INCREMENT=1000 DEFAULT CHARSET=utf8 COMMENT='秒杀库存表';
-- 初始化数据
insert into
seckill(name, number, start_time, end_time)
values
('1000元秒杀iphon6', 100, '2015-11-01 00:00:00', '2015-11-02 00:00:00'),
('500元秒杀ipadmini2', 200, '2016-06-24 00:00:00', '2016-06-25 00:00:00'),
('300元秒杀小米手机', 300, '2016-06-26 00:00:00', '2015-06-27 00:00:00'),
('1999元秒杀ipadAir', 400, '2016-06-29 00:00:00', '2016-06-30 00:00:00'),
('5999元秒杀macbook', 500, '2016-06-29 00:00:00', '2016-06-30 00:00:00');
-- 秒杀成功明细表
-- 用户登录相关的信息
CREATE TABLE success_killed(
seckill_id bigint NOT NULL COMMENT '商品库存id',
user_phone bigint NOT NULL COMMENT '用户手机号',
state tinyint NOT NULL DEFAULT -1 COMMENT '状态标识:-1:无效 0:成功 1:已付款',
create_time timestamp NOT NULL COMMENT '创建时间',
PRIMARY KEY (seckill_id, user_phone),
KEY idx_create_time(create_time)
)ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='秒杀成功明细表';
这里有两个表：seckill和success_killed表。
我们需要两个包：（1）org.seckill.entity包（保存实体） （2）org.seckill.dao包（保存与实体对应的DAO）
主要分三步：首先在src/main/java下的 org.seckill.entity 包创建实体
然后在src/main/java下的 org.seckill.dao 包创建对应的DAO
最后在src/main/resources下的mapper文件夹下创建对应的 XXXDao.xml 配置文件（SQL语句写在配置文件中）
第一步：创建实体
Seckill. java文件：
package org.seckill.entity;
import java.util.Date;
public class Seckill {
private long seckillId;
private String name;
private int number;
private Date createTime;
private Date startTime;
private Date endTime;
public long getSeckillId() {
return seckillId;
}
public void setSeckillId(long seckillId) {
this.seckillId = seckillId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
public Date getStartTime() {
return startTime;
}
public void setStartTime(Date startTime) {
this.startTime = startTime;
}
public Date getEndTime() {
return endTime;
}
public void setEndTime(Date endTime) {
this.endTime = endTime;
}
//复写toString()方法
@Override
public String toString() {
return "Seckill [seckillId=" + seckillId + ", name=" + name
+ ", number=" + number + ", createTime=" + createTime
+ ", startTime=" + startTime + ", endTime=" + endTime + "]";
}
}
SuccessKilled.java文件：
package org.seckill.entity;
import java.util.Date;
public class SuccessKilled {
private long seckillId;
private long userPhone;
private short state; //状态标识:-1:无效 0:成功 1:已付款
private Date createTime;
//多对一：多个SuccessKilled对应一个Seckill
private Seckill seckill;
public long getSeckillId() {
return seckillId;
}
public void setSeckillId(long seckillId) {
this.seckillId = seckillId;
}
public long getUserPhone() {
return userPhone;
}
public void setUserPhone(long userPhone) {
this.userPhone = userPhone;
}
public short getState() {
return state;
}
public void setState(short state) {
this.state = state;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
public Seckill getSeckill() {
return seckill;
}
public void setSeckill(Seckill seckill) {
this.seckill = seckill;
}
@Override
public String toString() {
return "SuccessKilled [seckillId=" + seckillId + ", userPhone="
+ userPhone + ", state=" + state + ", createTime=" + createTime
+ "]";
}
}
第二步：创建DAO
（注意：当DAO类中的方法有多个形参的时候，需要通过注解@Param("XXX")来告诉Mybatis需要的参数）
SeckillDao.java文件：
package org.seckill.dao;
import java.util.Date;
import java.util.List;
import org.apache.ibatis.annotations.Param;
import org.seckill.entity.Seckill;
public interface SeckillDao {
/**
* 减库存
* @param seckillId
* @param killTime
* @return 如果返回>1， 表示更新的记录行数
*/
int reduceNumber(@Param("seckillId") long seckillId, @Param("killTime") Date killTime);
/**
* 根据ID查询秒杀对象
* @param seckillId
* @return
*/
Seckill queryById(long seckillId);
/**
* 根据偏移量查询秒杀商品列表
* @param offset
* @param limit
* @return
*/
List<Seckill> queryAll(@Param("offset") int offset, @Param("limit") int limit);
}
SuccessKilledDao.java文件：
package org.seckill.dao;
import org.apache.ibatis.annotations.Param;
import org.seckill.entity.SuccessKilled;
public interface SuccessKilledDao {
/**
* 插入购买明细，可过滤重复
* @param seckillId
* @param userPhone
* @return 返回插入结果的数量
*/
int insertSuccessKilled(@Param("seckillId") long seckillId, @Param("userPhone") long userPhone);
/**
* 根据id查询SuccessKilled并携带秒杀商品对象
* @param seckillId
* @return
*/
SuccessKilled queryByIdWithSeckill(@Param("seckillId") long seckillId, @Param("userPhone") long userPhone);
}
第三步：DAO的配置文件
SeckillDao.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- 目的：为DAO借口方法提供sql语句配置 -->
<mapper namespace="org.seckill.dao.SeckillDao">
<update id="reduceNumber">
update
seckill
set
number = number -1
where seckill_id = #{seckillId}
and start_time <![CDATA[ <= ]]> #{killTime}
and end_time <![CDATA[ >= ]]> #{killTime}
and number <![CDATA[ > ]]> 0;
</update>
<select id="queryById" resultType="Seckill" parameterType="long">
select seckill_id, name, number, start_time, end_time, create_time
from seckill
where seckill_id = #{seckillId}
</select>
<select id="queryAll" resultType="Seckill" parameterType="int">
select seckill_id, name, number, start_time, end_time, create_time
from seckill
order by create_time desc
limit #{offset},#{limit}
</select>
</mapper>
SuccessKilledDao.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.seckill.dao.SuccessKilledDao">
<insert id="insertSuccessKilled" parameterType="long">
<!-- 主键冲突，报错 ，用ignore解决冲突 -->
insert ignore into success_killed(seckill_id, user_phone, state)
values
(#{seckillId},#{userPhone}, 0)
</insert>
<select id="queryByIdWithSeckill" resultType="SuccessKilled" parameterType="long">
select
sk.seckill_id,
sk.user_phone,
sk.state,
sk.create_time,
s.seckill_id as "seckill.seckill_id",
s.name as "seckill.name",
s.number as "seckill.number",
s.start_time "seckill.start_time",
s.end_time as "seckill.end_time",
s.create_time as "seckill.create_time"
from success_killed sk
inner join seckill s on sk.seckill_id = s.seckill_id
where sk.seckill_id = #{seckillId} and sk.user_phone = #{userPhone}
</select>
</mapper>
在单元测试类中，需要做一下预处理：
/**
*配置spring和junit整合，junit启启动时候加载spring IOC容器
*spring-test,junit
*/
@RunWith(SpringJUnit4ClassRunner.class)
//告诉junit spring配置文件的位置
@ContextConfiguration({"classpath:spring/spring-dao.xml"})
随后在类中，使用注解@Resource 注入依赖
1、SeckillDaoTest.java文件
package org.seckill.dao;
import java.util.Date;
import java.util.List;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import javax.annotation.Resource;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.seckill.entity.Seckill;
import org.springframework.test.context.ContextConfiguration;
/**
*配置spring和junit整合，junit启启动时候加载spring IOC容器
*spring-test,junit
*/
@RunWith(SpringJUnit4ClassRunner.class)
//告诉junit spring配置文件的位置
@ContextConfiguration({"classpath:spring/spring-dao.xml"})
public class SeckillDaoTest {
//注入Dao实现依赖
@Resource
private SeckillDao seckillDao;
@Test
public void testReduceNumber() throws Exception {
Date killTime = new Date();
int updateCount = seckillDao.reduceNumber(1000L, killTime);
System.out.println(updateCount);
}
@Test
public void testQueryById() throws Exception {
long id = 1000;
Seckill seckill = seckillDao.queryById(id);
System.out.println(seckill.getName());
System.out.println(seckill);
}
@Test
public void testQueryAll() throws Exception {
List<Seckill> seckills = seckillDao.queryAll(0, 100);
for(Seckill seckill : seckills) {
System.out.println(seckill);
}
}
}
2、SuccessKilledDaoTest.java
package org.seckill.dao;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import javax.annotation.Resource;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.seckill.entity.SuccessKilled;
import org.springframework.test.context.ContextConfiguration;
/**
*配置spring和junit整合，junit启启动时候加载spring IOC容器
*spring-test,junit
*/
@RunWith(SpringJUnit4ClassRunner.class)
//告诉junit spring配置文件的位置
@ContextConfiguration({"classpath:spring/spring-dao.xml"})
public class SuccessKilledDaoTest {
@Resource
private SuccessKilledDao successKilledDao;
@Test
public void testInsertSuccessKilled() throws Exception {
long id = 1001L;
long phone = 18945681316L;
int insertCount = successKilledDao.insertSuccessKilled(id, phone);
System.out.println("insertCount= " + insertCount);
}
@Test
public void testQueryByIdWithSeckill() throws Exception {
long id = 1001L;
long phone = 18945681316L;
SuccessKilled successKilled = successKilledDao.queryByIdWithSeckill(id, phone);
System.out.println(successKilled);
System.out.println(successKilled.getSeckill());
}
}
以上便是整个DAO层的设计与配置！！
课程收获：1、学习了如何通过maven创建web项目，pom.xml 文件依赖管理。
2、学习如何整合spring+mybatis
3、学习了相关配置文件的书写。
一、使用maven创建web项目
创建过程省略。。。创建完毕，目录结构如下：
相关说明：src/main/java下面放 java代码
src/main/resources下面放 配置文件等。
src/test/是相关 单元测试的文件。
可以新建一个src/test/sql/ 下面存放 创建数据库和表格的SQL源码
首先需要修改web.xml中的servlet版本：
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0"
metadata-complete="true">
<!-- 修改servlet版本 -->
</web-app>
创建完毕之后需要填写pom.xml文件，常用的依赖包已经配置在pom.xml之中，具体如下：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.seckill</groupId>
<artifactId>seckill</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>seckill Maven Webapp</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<!-- 使用junit4 -->
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!-- 补全项目的依赖 -->
<!-- 1:日志 java日志：slf4j, log4j, logback, common-logging
slf4j 是规范/接口
日志实现：log4j, logback, common-logging
使用：slf4j + logback
-->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.12</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.1.2</version>
</dependency>
<!-- 2:数据库相关依赖 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
<scope>runtime</scope>
</dependency>
<!-- 数据库连接池c3p0 -->
<dependency>
<groupId>c3p0</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.1.2</version>
</dependency>
<!-- DAO框架Mybatis依赖 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.8</version>
</dependency>
<!-- Mybatis自身实现的spring整合依赖 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>1.2.3</version>
</dependency>
<!-- 3：servlet web相关依赖 -->
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.7.4</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
<!-- 4：spring依赖 -->
<!-- 1) spring核心 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<!-- 2) spring DAO层依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<!-- 3) spring web相关依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
<!-- 4) spring test相关依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>4.2.6.RELEASE</version>
</dependency>
</dependencies>
</project>
至此，一个整合spring+mybatis 的 web项目基本搭建完毕！！
二、连接数据库相关配置
如下图，在src/main/resources 下创建jdbc.properties 文件（驱动、url、用户名、密码等设置）在src/main/resources 下创建mybatis-config.xml 文件（配置mybatis全局属性）
在src/main/resources下新建文件夹spring和mapper：spring下主要存spring相关配置文件，mapper主要存DAO的相关映射。
在src/main/resources/spring/下创建文件spring-dao.xml 文件（配置连接数据库，整合mybatis配置）
jdbc.properties文件内容：（注意变量名必须这样写，不能自定义）
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql://localhost:3306/seckill?useUnicode=true&characterEncoding=utf8
jdbc.user=tao
jdbc.password=password
mybatis-config.xml文件内容：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 配置全局属性 -->
<settings>
<!-- 使用jdbc的getGeneratedKeys获取数据库自增主键值 -->
<setting name="useGeneratedKeys" value="true"/>
<!-- 使用列别名替换列名 默认：true -->
<setting name="useColumnLabel" value="true"/>
<!-- 开启驼峰命名自动转换 -->
<setting name="mapUnderscoreToCamelCase" value="true"/>
</settings>
</configuration>
spring-dao.xml文件内容：（注意：classpath指代的是src/main/java和src/main/resources）
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/2002/xmlspec/dtd/2.10/xmlspec.dtd">
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!-- 配置整合mybatis过程 -->
<!-- 1:配置数据库相关参数 properties的属性：${url} -->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!-- 2:数据库的连接池 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<!-- 配置连接池属性 -->
<property name="driverClass" value="${jdbc.driverClass}"></property>
<property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
<property name="user" value="${jdbc.user}"></property>
<property name="password" value="${jdbc.password}"></property>
<!--连接池中保留的最小连接数。-->
<property name="minPoolSize" value="10"></property>
<!--连接池中保留的最大连接数。Default: 15 -->
<property name="maxPoolSize" value="30"></property>
<!--关闭连接后不自动commit -->
<property name="autoCommitOnClose" value="false"></property>
<!-- 获取连接超时时间 -->
<property name="checkoutTimeout" value="1000"></property>
<!--定义在从数据库获取新连接失败后重复尝试的次数。Default: 30 -->
<property name="acquireRetryAttempts" value="2" />
</bean>
<!-- 3:配置SqlSessionFactory对象 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 注入c3p0数据库连接池 -->
<property name="dataSource" ref="dataSource" />
<!-- 配置mybatis全局配置文件：mybatis-config.xml -->
<property name="configLocation" value="classpath:mybatis-config.xml"></property>
<!-- 扫描entity包，使用别名 -->
<property name="typeAliasesPackage" value="org.seckill.entity"></property>
<!-- 扫描sql配置文件：mapper需要的xml文件 -->
<property name="mapperLocations" value="classpath:mapper/*.xml"></property>
</bean>
<!-- 4:配置扫描Dao接口包，动态实现Dao接口，注入到spring容器中 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!-- 注入sqlSessionFactroy -->
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
<!-- 给出扫描Dao接口包 -->
<property name="basePackage" value="org.seckill.dao" />
</bean>
</beans>
（注意：代码中高亮部分相关文件的位置可以根据具体项目进行填写）
至此，基本配置完毕！
三、编写DAO以及DAO映射
在编写DAO之前，需要创建数据库表格（创建过程省略。。。）相关SQL语句：schema.sql文件
-- 数据库初始化脚本
-- 创建数据库
CREATE DATABASE seckill;
-- 使用数据库
use seckill;
-- 创建秒杀库存表
CREATE TABLE seckill(
seckill_id bigint NOT NULL AUTO_INCREMENT COMMENT '商品库存id',
name varchar(120) NOT NULL COMMENT '商品名称',
number int NOT NULL COMMENT '库存数量',
create_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
start_time DATETIME NOT NULL COMMENT '秒杀开启时间',
end_time DATETIME NOT NULL COMMENT '秒杀结束时间',
PRIMARY KEY(seckill_id),
key idx_start_time(start_time),
key idx_end_time(end_time),
key idx_create_time(create_time)
)ENGINE=InnoDB AUTO_INCREMENT=1000 DEFAULT CHARSET=utf8 COMMENT='秒杀库存表';
-- 初始化数据
insert into
seckill(name, number, start_time, end_time)
values
('1000元秒杀iphon6', 100, '2015-11-01 00:00:00', '2015-11-02 00:00:00'),
('500元秒杀ipadmini2', 200, '2016-06-24 00:00:00', '2016-06-25 00:00:00'),
('300元秒杀小米手机', 300, '2016-06-26 00:00:00', '2015-06-27 00:00:00'),
('1999元秒杀ipadAir', 400, '2016-06-29 00:00:00', '2016-06-30 00:00:00'),
('5999元秒杀macbook', 500, '2016-06-29 00:00:00', '2016-06-30 00:00:00');
-- 秒杀成功明细表
-- 用户登录相关的信息
CREATE TABLE success_killed(
seckill_id bigint NOT NULL COMMENT '商品库存id',
user_phone bigint NOT NULL COMMENT '用户手机号',
state tinyint NOT NULL DEFAULT -1 COMMENT '状态标识:-1:无效 0:成功 1:已付款',
create_time timestamp NOT NULL COMMENT '创建时间',
PRIMARY KEY (seckill_id, user_phone),
KEY idx_create_time(create_time)
)ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='秒杀成功明细表';
这里有两个表：seckill和success_killed表。
我们需要两个包：（1）org.seckill.entity包（保存实体） （2）org.seckill.dao包（保存与实体对应的DAO）
主要分三步：首先在src/main/java下的 org.seckill.entity 包创建实体
然后在src/main/java下的 org.seckill.dao 包创建对应的DAO
最后在src/main/resources下的mapper文件夹下创建对应的 XXXDao.xml 配置文件（SQL语句写在配置文件中）
第一步：创建实体
Seckill. java文件：
package org.seckill.entity;
import java.util.Date;
public class Seckill {
private long seckillId;
private String name;
private int number;
private Date createTime;
private Date startTime;
private Date endTime;
public long getSeckillId() {
return seckillId;
}
public void setSeckillId(long seckillId) {
this.seckillId = seckillId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
public Date getStartTime() {
return startTime;
}
public void setStartTime(Date startTime) {
this.startTime = startTime;
}
public Date getEndTime() {
return endTime;
}
public void setEndTime(Date endTime) {
this.endTime = endTime;
}
//复写toString()方法
@Override
public String toString() {
return "Seckill [seckillId=" + seckillId + ", name=" + name
+ ", number=" + number + ", createTime=" + createTime
+ ", startTime=" + startTime + ", endTime=" + endTime + "]";
}
}
SuccessKilled.java文件：
package org.seckill.entity;
import java.util.Date;
public class SuccessKilled {
private long seckillId;
private long userPhone;
private short state; //状态标识:-1:无效 0:成功 1:已付款
private Date createTime;
//多对一：多个SuccessKilled对应一个Seckill
private Seckill seckill;
public long getSeckillId() {
return seckillId;
}
public void setSeckillId(long seckillId) {
this.seckillId = seckillId;
}
public long getUserPhone() {
return userPhone;
}
public void setUserPhone(long userPhone) {
this.userPhone = userPhone;
}
public short getState() {
return state;
}
public void setState(short state) {
this.state = state;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
public Seckill getSeckill() {
return seckill;
}
public void setSeckill(Seckill seckill) {
this.seckill = seckill;
}
@Override
public String toString() {
return "SuccessKilled [seckillId=" + seckillId + ", userPhone="
+ userPhone + ", state=" + state + ", createTime=" + createTime
+ "]";
}
}
第二步：创建DAO
（注意：当DAO类中的方法有多个形参的时候，需要通过注解@Param("XXX")来告诉Mybatis需要的参数）
SeckillDao.java文件：
package org.seckill.dao;
import java.util.Date;
import java.util.List;
import org.apache.ibatis.annotations.Param;
import org.seckill.entity.Seckill;
public interface SeckillDao {
/**
* 减库存
* @param seckillId
* @param killTime
* @return 如果返回>1， 表示更新的记录行数
*/
int reduceNumber(@Param("seckillId") long seckillId, @Param("killTime") Date killTime);
/**
* 根据ID查询秒杀对象
* @param seckillId
* @return
*/
Seckill queryById(long seckillId);
/**
* 根据偏移量查询秒杀商品列表
* @param offset
* @param limit
* @return
*/
List<Seckill> queryAll(@Param("offset") int offset, @Param("limit") int limit);
}
SuccessKilledDao.java文件：
package org.seckill.dao;
import org.apache.ibatis.annotations.Param;
import org.seckill.entity.SuccessKilled;
public interface SuccessKilledDao {
/**
* 插入购买明细，可过滤重复
* @param seckillId
* @param userPhone
* @return 返回插入结果的数量
*/
int insertSuccessKilled(@Param("seckillId") long seckillId, @Param("userPhone") long userPhone);
/**
* 根据id查询SuccessKilled并携带秒杀商品对象
* @param seckillId
* @return
*/
SuccessKilled queryByIdWithSeckill(@Param("seckillId") long seckillId, @Param("userPhone") long userPhone);
}
第三步：DAO的配置文件
SeckillDao.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- 目的：为DAO借口方法提供sql语句配置 -->
<mapper namespace="org.seckill.dao.SeckillDao">
<update id="reduceNumber">
update
seckill
set
number = number -1
where seckill_id = #{seckillId}
and start_time <![CDATA[ <= ]]> #{killTime}
and end_time <![CDATA[ >= ]]> #{killTime}
and number <![CDATA[ > ]]> 0;
</update>
<select id="queryById" resultType="Seckill" parameterType="long">
select seckill_id, name, number, start_time, end_time, create_time
from seckill
where seckill_id = #{seckillId}
</select>
<select id="queryAll" resultType="Seckill" parameterType="int">
select seckill_id, name, number, start_time, end_time, create_time
from seckill
order by create_time desc
limit #{offset},#{limit}
</select>
</mapper>
SuccessKilledDao.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.seckill.dao.SuccessKilledDao">
<insert id="insertSuccessKilled" parameterType="long">
<!-- 主键冲突，报错 ，用ignore解决冲突 -->
insert ignore into success_killed(seckill_id, user_phone, state)
values
(#{seckillId},#{userPhone}, 0)
</insert>
<select id="queryByIdWithSeckill" resultType="SuccessKilled" parameterType="long">
select
sk.seckill_id,
sk.user_phone,
sk.state,
sk.create_time,
s.seckill_id as "seckill.seckill_id",
s.name as "seckill.name",
s.number as "seckill.number",
s.start_time "seckill.start_time",
s.end_time as "seckill.end_time",
s.create_time as "seckill.create_time"
from success_killed sk
inner join seckill s on sk.seckill_id = s.seckill_id
where sk.seckill_id = #{seckillId} and sk.user_phone = #{userPhone}
</select>
</mapper>
四、DAO的单元测试
单元测试的java文件保存在src/test/java下的相关包中。如下图：在单元测试类中，需要做一下预处理：
/**
*配置spring和junit整合，junit启启动时候加载spring IOC容器
*spring-test,junit
*/
@RunWith(SpringJUnit4ClassRunner.class)
//告诉junit spring配置文件的位置
@ContextConfiguration({"classpath:spring/spring-dao.xml"})
随后在类中，使用注解@Resource 注入依赖
1、SeckillDaoTest.java文件
package org.seckill.dao;
import java.util.Date;
import java.util.List;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import javax.annotation.Resource;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.seckill.entity.Seckill;
import org.springframework.test.context.ContextConfiguration;
/**
*配置spring和junit整合，junit启启动时候加载spring IOC容器
*spring-test,junit
*/
@RunWith(SpringJUnit4ClassRunner.class)
//告诉junit spring配置文件的位置
@ContextConfiguration({"classpath:spring/spring-dao.xml"})
public class SeckillDaoTest {
//注入Dao实现依赖
@Resource
private SeckillDao seckillDao;
@Test
public void testReduceNumber() throws Exception {
Date killTime = new Date();
int updateCount = seckillDao.reduceNumber(1000L, killTime);
System.out.println(updateCount);
}
@Test
public void testQueryById() throws Exception {
long id = 1000;
Seckill seckill = seckillDao.queryById(id);
System.out.println(seckill.getName());
System.out.println(seckill);
}
@Test
public void testQueryAll() throws Exception {
List<Seckill> seckills = seckillDao.queryAll(0, 100);
for(Seckill seckill : seckills) {
System.out.println(seckill);
}
}
}
2、SuccessKilledDaoTest.java
package org.seckill.dao;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import javax.annotation.Resource;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.seckill.entity.SuccessKilled;
import org.springframework.test.context.ContextConfiguration;
/**
*配置spring和junit整合，junit启启动时候加载spring IOC容器
*spring-test,junit
*/
@RunWith(SpringJUnit4ClassRunner.class)
//告诉junit spring配置文件的位置
@ContextConfiguration({"classpath:spring/spring-dao.xml"})
public class SuccessKilledDaoTest {
@Resource
private SuccessKilledDao successKilledDao;
@Test
public void testInsertSuccessKilled() throws Exception {
long id = 1001L;
long phone = 18945681316L;
int insertCount = successKilledDao.insertSuccessKilled(id, phone);
System.out.println("insertCount= " + insertCount);
}
@Test
public void testQueryByIdWithSeckill() throws Exception {
long id = 1001L;
long phone = 18945681316L;
SuccessKilled successKilled = successKilledDao.queryByIdWithSeckill(id, phone);
System.out.println(successKilled);
System.out.println(successKilled.getSeckill());
}
}
以上便是整个DAO层的设计与配置！！
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