[SSM project: Java high concurrency spike API] 1 business analysis and DAO layer

1. Project overview

1.1 SSM framework advantages

The framework is easy to use and lightweight
Low code intrusion
Mature community and user base

1.2 introduction to relevant technologies

1.MySQL

Table design
SQL skills
Transaction and row level locks

2.MyBatis

Design and development of DAO layer
MyBatis rational use
MyBatis and Spring integration

3.Spring

Spring IOC integration Service
Declarative transaction application

4.SpringMVC

Restful interface design and use
Framework operation process
Controller development skills

5. Front end

Interaction design
Bootstrap
jQuery

6. High concurrency

High concurrency point and high concurrency analysis
Optimize ideas and implement

1.3 second kill business analysis

1.3. 1. Business process of second kill system

1.3. 2. The core of second kill business: inventory processing

1.3. 3 why transactions are needed

1.3. 4. Data landing

MySQL VS NoSQL

NoSQL: the transaction support is not very good, and the pursuit is performance, high availability and distributed
MySQL: the built-in transaction mechanism is still the most effective and reliable data landing scheme at present - > inventory reduction and purchase behavior can be recorded more reliably

1.4 difficulty analysis of MySQL second kill

Difficult problem: Competition - > transaction + row level lock

Transaction working mechanism:

Start Transaction
Update inventory quantity - > competition appears here
Insert purchase details
Commit

Row level lock - > with competition

How to deal with competition efficiently: high concurrency

1.5 what second kill functions can be realized

Second kill interface exposure
Execute second kill
Related query: List query and detail page query

Code development phase

DAO design coding: database table design, Dao interface, and how MyBatis implements Dao
Service design code:
Service interface design and coding implementation, managing services through Spring, and labeling services through Spring declarative transactions. The method is a transaction operation to simplify transaction control
Web design coding: Restful interface, front-end interaction

2. Create projects and dependencies

2.1 description before creation

Create from scratch
Obtain relevant configurations from the official website
1. More comprehensive and authoritative documents
2. Avoid obsolescence or errors
Create a project using Maven

2.2 start creating project

New Maven project
Maven installation and its configuration and use in IDEA (nanny tutorial)
New Web project
Java learning [framework (III)] spring MVC (I) review MVC Architecture & Servlet

The results are as follows:

2.3 import dependency

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.seckill</groupId>
    <artifactId>seckill</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <!-- use junit4(3.0 Programming mode is used by default, 4.0 Run in annotation mode later junit)-->
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>

        <!-- Complete project dependency -->

        <!-- 1:journal java journal: slf4j, log4j, logback, common-logging
             slf4j Is the norm/Interface
             Log implementation: log4j, logback, common-logging
             use: 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>1.1.1</version>
        </dependency>
        <!-- realization slf4j Interface and integration -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.1.1</version>
        </dependency>

        <!-- 2. Database dependency -->
        <!-- mysql drive-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.35</version>
            <scope>runtime</scope>
        </dependency>
        <!-- Database connection pool-->
        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.1.2</version>
        </dependency>

        <!-- 3. DAO Frame: MyBatis rely on -->
        <!-- MyBatis Self dependence -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.3.0</version>
        </dependency>
        <!-- MyBatis Self implemented Spring Integration dependence -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.2.3</version>
        </dependency>

        <!-- 3. Servlet web Correlation dependency -->
        <!-- jsp Corresponding label -->
        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
        </dependency>
        <!-- js Default label Library -->
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <!-- SpringMVC Default needs jackson -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.5.4</version>
        </dependency>
        <!-- servlet -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>

        <!-- 4. Spring rely on-->
        <!-- 1)Spring Core dependency-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <!-- 2) Spring DAO Layer dependence -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <!-- Spring Transaction dependency -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <!-- 3) Spring web Correlation dependency-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <!-- 4) Spring test Related dependencies (for unit testing) -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>

    </dependencies>
</project>

3. Database design code

Java learning [framework (II)] MyBatis (I) the first MyBatis query program

Create a new schema under main sql
(I connected to the database, but I didn't connect to MyBatis - > crazy MyBatis was configured in the resource. As of this step, I haven't configured it yet)

schema. The SQL statements in SQL are as follows:

-- Database initialization script

-- Create database
CREATE  DATABASE `seckill`;

-- Use database
use `seckill`;

-- Create a second kill inventory table
CREATE TABLE `seckill`(
`seckill_id` bigint NOT NULL AUTO_INCREMENT COMMENT 'Commodity inventory id',
`name` varchar(120) NOT NULL COMMENT 'Trade name',
`number` int NOT NULL COMMENT 'Inventory quantity',
`start_time` datetime NOT NULL COMMENT 'Spike start time',
`end_time` datetime NOT NULL COMMENT 'Spike end time',
`create_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT 'Creation time',
-- Design index
-- idx by index abbreviation
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 'Second kill inventory Watch';

-- Initialization data
insert into
    `seckill`(`name`, `number`, `start_time`, `end_time`)
values
    ('1000 Yuan second kill iphone6',  100, '2015-11-01 00:00:00', '2015-11-02 00:00:00'),
    ('500 Yuan second kill ipad2',  200, '2015-11-01 00:00:00', '2015-11-02 00:00:00'),
    ('300 Yuan spike millet 4',  300, '2015-11-01 00:00:00', '2015-11-02 00:00:00'),
    ('200 Yuan second kill red rice note',  400, '2015-11-01 00:00:00', '2015-11-02 00:00:00');

-- Second kill success details
-- Information related to user login authentication
create table `success_killed`(
`seckill_id` bigint NOT NULL COMMENT 'Second kill commodity id',
`user_phone` bigint NOT NULL COMMENT 'User mobile number',
`state` tinyint NOT NULL DEFAULT -1 COMMENT 'Status identification: -1: Invalid 0: Success 1: Paid 2: Shipped',
`create_time` datetime NOT NULL COMMENT 'Creation time',
PRIMARY KEY (`seckill_id`, `user_phone`),  -- composite keys 
key idx_create_time(create_time)
)ENGINE = InnoDB DEFAULT CHARSET = utf8 COMMENT 'Second kill success details';

Modify database field properties:

ALTER TABLE `success_killed` MODIFY `create_time` datetime;

Show how tables are created:

show CREATE TABLE `success_killed`;

CREATE TABLE `success_killed` (
  `seckill_id` bigint(20) NOT NULL COMMENT 'Second kill commodity id',
  `user_phone` bigint(20) NOT NULL COMMENT 'User mobile number',
  `state` tinyint(4) NOT NULL DEFAULT '-1' COMMENT 'Status identification: -1: Invalid 0: Success 1: Paid 2: Shipped',
  `create_time` datetime DEFAULT NULL,
  PRIMARY KEY (`seckill_id`,`user_phone`),
  KEY `idx_create_time` (`create_time`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='Second kill success details'

The results are as follows:

4. DAO layer entity and interface coding

Correspondence between label and entity

The table corresponds to the entity class in Java
Column corresponds to the attribute in the entity

Create entity package & Dao layer package
org.seckill.entity
org.seckill.dao

4.1 writing entity classes

4.1.1 Seckill entity class

package org.seckill.entity;

import java.util.Date;

public class Seckill {
    private long seckillId;
    private String name;
    private int number;
    private Date startTime;
    private Date endTime;
    private Date createTime;

    // Alt + insert
    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 getStartTime() {
        return startTime;
    }

    public void setStartTime(Date startTime) {
        this.startTime = startTime;
    }

    public Date getEndTime() {
        return endTime;
    }

    public void setEndTime(Date endTime) {
        this.endTime = endTime;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    @Override
    public String toString() {
        return "Seckill{" +
                "seckillId=" + seckillId +
                ", name='" + name + '\'' +
                ", number=" + number +
                ", startTime=" + startTime +
                ", endTime=" + endTime +
                ", createTime=" + createTime +
                '}';
    }
}

4.1. 2 class successkilled

package org.seckill.entity;

import java.util.Date;

public class SuccessKilled {
    private long skillId;
    private long userPhone;
    private short state;
    private Date createTime;

    // Flexible
    // Many to one (composite attribute): one Seckill entity corresponds to multiple successful Seckill records
    private Seckill seckill;

    public long getSkillId() {
        return skillId;
    }

    public void setSkillId(long skillId) {
        this.skillId = skillId;
    }

    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{" +
                "skillId=" + skillId +
                ", userPhone=" + userPhone +
                ", state=" + state +
                ", createTime=" + createTime +
                '}';
    }
}

4.2 design DAO interface

4.2.1 SeckillDao interface

Naming convention: corresponding entity + Dao - > e.g. SeckillDao

package org.seckill.dao;

import org.seckill.entity.Seckill;

import java.util.Date;
import java.util.List;

public interface SeckillDao {

    // Inventory reduction (killTime the time when inventory reduction is performed corresponds to the createtime in the database)
    // If the number of affected rows > 1, it indicates the number of updated record rows
    int reduceNumber(long seckillId, Date killTime);

    // Query requirements (query the second kill object according to id)
    Seckill queryById(long seckillId);

    // Query the second kill product list according to the offset
    // Offset: offset, limit: how many records are taken after the offset
    List<Seckill> queryAll(int offet, int limit);
}

4.2. 2 successkilledao interface

package org.seckill.dao;

import org.seckill.entity.SuccessKilled;

public interface SuccessKilledDao {

    // Insert purchase details to filter duplicates (joint unique primary key)
    // Number of rows inserted
    int insertSuccessKilled(long seckillId, long userPhone);

    // Query SuccessKilled by id and carry the second kill product object entity
    SuccessKilled queryByIdWithSeckill(long seckillId);
}

Keywords: Java MySQL Mybatis Spring Back-end

Added by carobee on Thu, 16 Dec 2021 18:40:31 +0200

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