SpringBoot--简单处理并发demo

我会带着你远行 2022-05-22 11:06 220阅读 0赞

## 目录结构：（只跟book相关的） ##

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## model： ##

package com.cxb.model;
    
    
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    import javax.persistence.Table;
    //自动生成表
    @Entity
    @Table(name="book")
    public class Book {
    
    
    @Id
    @GeneratedValue
    private Integer id;
    
    @Column(length=100)
    private String name;
    
    @Column(length=50)
    private String author;
    
    @Column(length=50)
    private Integer stock;   //库存
    
    public Integer getStock() {
    return stock;
    }
    public void setStock(Integer stock) {
    this.stock = stock;
    }
    public Integer getId() {
    return id;
    }
    public void setId(Integer id) {
    this.id = id;
    }
    public String getName() {
    return name;
    }
    public void setName(String name) {
    this.name = name;
    }
    public String getAuthor() {
    return author;
    }
    public void setAuthor(String author) {
    this.author = author;
    }
    
    
    }

## BookDao： ##

package com.cxb.dao;
    
    
    import java.util.List;
    
    
    import javax.transaction.Transactional;
    
    
    import org.springframework.data.domain.Page;
    import org.springframework.data.domain.Pageable;
    import org.springframework.data.domain.Slice;
    import org.springframework.data.jpa.repository.JpaRepository;
    import org.springframework.data.jpa.repository.Modifying;
    import org.springframework.data.jpa.repository.Query;
    
    
    import com.cxb.model.Book;
    /**
     * springbootJPA
     *       这种就不需要写service类，直接在controller里面调用该dao的方法
     * @author 81046
     *
     */
    public interface BookDao extends JpaRepository<Book, Integer>{
    
    //And --- 等价于 SQL 中的 and 关键字
    public List<Book> findByNameAndStock(String name,int stock);
    
    // Or --- 等价于 SQL 中的 or 关键字
    public List<Book> findByNameOrStock(String name,int stock);
    
    //Between --- 等价于 SQL 中的 between 关键字
    public List<Book> findByStockBetween(int min,int max);
    
    //LessThan --- 等价于 SQL 中的 "<"
    public List<Book> findByStockLessThan(int max);
    
    //GreaterThan --- 等价于 SQL 中的">"  
    public List<Book> findByStockGreaterThan(int min);  
    
    //IsNull --- 等价于 SQL 中的 "is null"
    public List<Book> findByNameIsNull();
    
    //IsNotNull --- 等价于 SQL 中的 "is not null"
    public List<Book> findByNameIsNotNull();  
    
    //NotNull --- 与 IsNotNull 等价
    public List<Book> findByNameNotNull(); 
    
    //Like --- 等价于 SQL 中的 "like"
    public List<Book> findByNameLike(String name); 
    
    //NotLike --- 等价于 SQL 中的 "not like"
    public List<Book> findByNameNotLike(String name); 
    
    //OrderBy --- 等价于 SQL 中的 "order by"
    public List<Book> findByNameNotNullOrderByStockAsc();  
    
    //Not --- 等价于 SQL 中的 "！ ="
    public List<Book> findByNameNot(String name);
    
    //In --- 等价于 SQL 中的 "in"
    public List<Book> findByNameIn(String name);
    
    //NotIn --- 等价于 SQL 中的 "not in"
    public List<Book> findByNameNotIn(String name);
    
    
    //***************************************
    //利用原生的sql进行操作
    
    // @Query 注解中编写 JPQL 语句
    // 使用 @Modifying 进行修饰. 以通知 　　SpringData， 这是一个 UPDATE 或 DELETE 操作
    @Query(value="select * from book where name = ?1 ",nativeQuery=true)
    @Modifying
    public List<Book> findBookByName(String name);
    
    
    @Query(value="delete from book where id = ?1 ",nativeQuery=true)
    @Modifying
    @Transactional
    public void deleteBookById(int id);
    
    
    //利用原生的SQL进行修改操作  
       @Query(value = "update book set name=?1 where id=?2 ", nativeQuery = true)  
       @Modifying 
       @Transactional
       public void updateBookName(String name,int id);  
       
       //利用原生的SQL进行插入操作  
       @Query(value = "insert into book(name,author) value(?1,?2)", nativeQuery = true)  
       @Modifying  
       @Transactional
       public void insertBook(String name,String author);  
       
       //分页查询 查询计算元素总个数总页数，数据多的情况下，代价是昂贵的  
       Page<Book> findByNameAndAuthor(String name ,String author,Pageable pageable);  
       
       //分页查询，返回的是一个片段，它只知道下一片段或者上一片段是否可用。  
       Slice<Book> findByName(String name,Pageable pageable); 
       
       //分页查询所有
       //分页查询 查询计算元素总个数总页数，数据多的情况下，代价是昂贵的  
       Page<Book> findAll(Pageable pageable); 
       
       @Query(value = "update book set stock=stock-?1 where id=?2", nativeQuery = true)  
       @Modifying  
       @Transactional
       public void reduce(int num,int id);
    
    }

## BookController： ##

package com.cxb.controller;
    
    
    import java.util.List;
    import java.util.concurrent.Semaphore;
    
    
    import javax.servlet.http.HttpServletRequest;
    
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.data.domain.Page;
    import org.springframework.data.domain.PageRequest;
    import org.springframework.data.domain.Pageable;
    import org.springframework.data.domain.Slice;
    import org.springframework.data.domain.Sort;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.ResponseBody;
    
    
    import com.cxb.dao.BookDao;
    import com.cxb.model.Book;
    
    
    @Controller
    @RequestMapping("/book")
    public class BookController {
    
    @Autowired
    private BookDao bookDao;
    
    //处理并发事件
    //定义资源的总数量
    Semaphore semaphore=new Semaphore(1);  
    
    /** 查询所有的图书
    * http://localhost:8080/book/list
    * @return   
    */
    @RequestMapping(value="/list", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public List<Book> list() {
    return bookDao.findAll();
    }
    
    /**
    * 新增图书
    * @param request
    * @return
    */
    @RequestMapping(value="/saveBook", method=RequestMethod.POST,produces = "application/json; charset=utf-8")
    @ResponseBody
    public Book saveBook(HttpServletRequest request) {
    String author = request.getParameter("author");
    String name = request.getParameter("name");
    String stock = request.getParameter("stock");
    Book book = new Book();
    book.setAuthor(author);
    book.setName(name);
    book.setStock(Integer.parseInt(stock));
    return bookDao.save(book);
    }
    
    /**
    * 修改图书
    * @param request
    * @return
    */
    @RequestMapping(value="/updateBook", method=RequestMethod.POST,produces = "application/json; charset=utf-8")
    @ResponseBody
    public Book updateBook(HttpServletRequest request) {
    String author = request.getParameter("author");
    String name = request.getParameter("name");
    String stock = request.getParameter("stock");
    Book book = new Book();
    book.setAuthor(author);
    //设置id之后，就会执行update
    book.setId(3);
    book.setName(name);
    book.setStock(Integer.parseInt(stock));
    return bookDao.save(book);
    }
    
    /**
    * 根据id删除图书
    * @param request
    */
    @RequestMapping(value="/delete", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public void delete(HttpServletRequest request) {
    String id = request.getParameter("id");
    bookDao.deleteById(Integer.parseInt(id));
    }
    
    /** 根据库存和名称查询图书
    * http://localhost:8080/book/findByNameAndStock?name=庐州月&stock=20
    * @param request
    * @return
    */
    @RequestMapping(value="/findByNameAndStock", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public List<Book> findByNameAndStock(HttpServletRequest request) {
    String name = request.getParameter("name");
    String stock = request.getParameter("stock");
    return bookDao.findByNameAndStock(name,Integer.parseInt(stock));
    }
    
    /** 根据名称或者库存查询图书
    * http://localhost:8080/book/findByNameOrStock?name=庐州月&stock=22
    * @param request
    * @return
    */
    @RequestMapping(value="/findByNameOrStock", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public List<Book> findByNameOrStock(HttpServletRequest request){
    String name = request.getParameter("name");
    String stock = request.getParameter("stock");
    //满足条件1和条件2的集合
    return bookDao.findByNameOrStock(name,Integer.parseInt(stock));
    }
    
    /**
    * 根据库存量在某个区间查询图书
    * @return
    */
    @RequestMapping(value="/findByStockBetween", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public List<Book> findByStockBetween(){
    //满足条件1和条件2的集合
    return bookDao.findByStockBetween(10,20);
    }
    
    /** 根据名称查询图书
    * http://localhost:8080/book/findBookByName?name=千百度
    * @param request
    * @return
    */
    @RequestMapping(value="/findBookByName", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public List<Book> findBookByName(HttpServletRequest request){
    String name = request.getParameter("name");
    return bookDao.findBookByName(name);
    }
    
    /** 根据id修改图书的名称
    * http://localhost:8080/book/updateBookName?name=叹服&id=1
    * @param request
    */
    @RequestMapping(value="/updateBookName", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public void updateBookName(HttpServletRequest request) {
    String name = request.getParameter("name");
    String id = request.getParameter("id");
    bookDao.updateBookName(name, Integer.parseInt(id));
    }
    
    /** 插入图书
    * http://localhost:8080/book/insertBook?name=千百度1&author=许嵩
    * @param request
    */
    @RequestMapping(value="/insertBook", method=RequestMethod.POST,produces = "application/json; charset=utf-8")
    @ResponseBody
    public void insertBook(HttpServletRequest request) {
    String name = request.getParameter("name");
    String author = request.getParameter("author");
    bookDao.insertBook(name, author);
    }
    
    /** 根据id删除图书
    * http://localhost:8080/book/deleteBookById?id=6
    * @param request   
    */
    @RequestMapping(value="/deleteBookById", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public void deleteBookById(HttpServletRequest request){
    String id = request.getParameter("id");
    bookDao.deleteById(Integer.parseInt(id));
    }
    
    /**
    * 分页查询图书 根据名称和作者
    * @param request
    * @return
    */
    @RequestMapping(value="/findByNameAndAuthor", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public Page<Book> findByNameAndAuthor(HttpServletRequest request){
    @SuppressWarnings("deprecation")
    //根据id降序
    Pageable pageable = new PageRequest(0,3, Sort.Direction.DESC,"id");
    String name = request.getParameter("name");
    String author = request.getParameter("author");
    return bookDao.findByNameAndAuthor(name, author, pageable);
    }
    
    
    /**
    * 分页查询所有的图书
    * @return
    */
    @RequestMapping(value="/findAll", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public Page<Book> findAll(){
    @SuppressWarnings("deprecation")
    //根据id降序
    Pageable pageable = new PageRequest(0,3, Sort.Direction.DESC,"id");
    return bookDao.findAll(pageable);
    }
    
    /**
    * 
    * @param request
    * @return
    */
    @RequestMapping(value="/findByName", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    Slice<Book> findByName(HttpServletRequest request){
    @SuppressWarnings("deprecation")
    //根据id降序
    Pageable pageable = new PageRequest(0,3, Sort.Direction.DESC,"id");
    String name = request.getParameter("name");
    return bookDao.findByName(name, pageable);
    }
    
    /**
    * 减库存   处理多线程（成功几个也会失败几个）
    */
    @RequestMapping(value="/reduce", method=RequestMethod.GET,produces = "application/json; charset=utf-8")
    @ResponseBody
    public String reduce(HttpServletRequest request){
    //可用资源数
    int availablePermits = semaphore.availablePermits();
    System.out.println("可用资源数量---"+availablePermits);
    if(availablePermits>0) {
    System.out.println("抢到资源****根据id修改该图书的库存");
    try {
    //请求占用一个资源
    semaphore.acquire(1);
    //根据id修改该图书的库存
    String id = request.getParameter("id");
    bookDao.reduce(5, Integer.parseInt(id));
    System.out.println("根据id修改该图书的库存完成");
    }catch (Exception e) {
    e.printStackTrace();
    }finally {
    //释放一个资源
    semaphore.release(1);
    }
    return "抢到资源处理业务逻辑，最后释放资源完成";
    }else {
    System.out.println("*********资源已被占用，稍后再试***********");
    return "*********资源已被占用，稍后再试***********";
    }
    
    }
    
    }

## SpringBootThymeleafApplication： ##

package com.cxb;
    
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
    import org.springframework.context.annotation.Bean;
    import org.springframework.http.converter.HttpMessageConverter;
    
    
    import com.alibaba.fastjson.serializer.SerializerFeature;
    import com.alibaba.fastjson.support.config.FastJsonConfig;
    import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
    
    
    @SpringBootApplication
    //没有连接数据库的时候报错  需要加上这一句
    //@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
    public class SpringBootThymeleafApplication {
    
    
    public static void main(String[] args) {
    SpringApplication.run(SpringBootThymeleafApplication.class, args);
    }
    
    /**
    * 这里是为了使用阿里的fastjson   方式一
    * @return
    */
    @Bean
    public HttpMessageConverters fastJsonConverters() {
    FastJsonHttpMessageConverter fastConverter=new FastJsonHttpMessageConverter();
    FastJsonConfig fastConfig=new FastJsonConfig();
    fastConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
    fastConverter.setFastJsonConfig(fastConfig);
    HttpMessageConverter<?> converter=fastConverter;
    return new HttpMessageConverters(converter);
    }
    
    }

## application.yml： ##

spring:
      thymeleaf:
        #缓冲的配置
        cache: false
        check-template: true
        check-template-location: true
        #开启MVC thymeleaf 视图解析
        enabled: true
        encoding: utf-8
        mode: HTML5
        prefix: classpath:/templates/
        suffix: .html
        
        
      #配置数据源
      datasource:
         url: jdbc:mysql://127.0.0.1:3306/sp?useUnicode=true&characterEncoding=utf8
         username: root
         password: 123456
         driver-class-name: com.mysql.jdbc.Driver
      
      jpa:
        hibernate:
          ddl-auto: update
          
        show-sql: true    
         
    #指定mybatis映射文件的地址
    mybatis:
      #配置文件的路径
      #config-location: classpath:mybatis-config.xml
      mapper-locations: classpath:mapper/*.xml 
      # mybatis自动扫描包中的实体类，自动定义别名，别名是类名(首字母大写或小写都可以,一般用小写)
      type-aliases-package: com.cxb.model
      
    
    
    #pagehelper分页插件配置
    pagehelper:
      helper-dialect: mysql
      reasonable: true
      support-methods-arguments: true
      params: countSql

## pom.xml ##

<?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>com.cxb</groupId>
    <artifactId>SpringBoot-Thymeleaf</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    
    
    <name>SpringBoot-Thymeleaf</name>
    <description>Demo project for Spring Boot</description>
    
    
    <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.2.RELEASE</version>
    <relativePath/> 
    </parent>
    
    
    <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    </properties>
    
    
    <dependencies>
    <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
    </dependency>
    
    
    <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <scope>runtime</scope>
    </dependency>
    <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
    </dependency>
    <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-tomcat</artifactId>
    <scope>provided</scope>
    </dependency>
    <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
    </dependency>
    
    
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    
    
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.4.1</version>
    </dependency>
    
    
    <dependency>
        <groupId>com.github.pagehelper</groupId>
        <artifactId>pagehelper-spring-boot-starter</artifactId>
        <version>1.2.3</version>
    </dependency>
    
    <dependency>
        <groupId>com.github.pagehelper</groupId>
        <artifactId>pagehelper</artifactId>
        <version>5.1.2</version>
    </dependency>
    
    <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.15</version>
            </dependency>
            
            <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    
    
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <scope>test</scope>
    </dependency>
    
    
    
    
    
    
    </dependencies>
    
    
    <build>
      <plugins>
        <plugin>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
      </plugins>
    </build>
    
    </project>

## 这里的测试可以用并发测试工具访问下面的链接： ##

###   链接：http://localhost:8080/book/reduce ###

![70 1][]

![70 2][]

[70]: /images/20220522/741ebbd23931402082f749ba06fe83e3.png
[70 1]: /images/20220522/c2d0200001c34c6f80135528de527aa2.png
[70 2]: /images/20220522/8b5adc1a6b9f43c2a06da7729ae0075d.png