学习笔记 : Spring Boot拥抱MyBatis及Redis ~

Spring Boot集成MyBatis

下面通过使用Spring Boot开发一个基于SSM的框架的应用,并通过一个简单的用户信息查询为例,记录如何在Spring Boot中使用MyBatis ~

  1. tb_user.sql : 用户信息数据表

    create table tb_user
    (
        id     int auto_increment primary key,
        name   varchar(15) not null,
        gender char        null,
        email  varchar(50) null
    );
  2. 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>
        <!-- lookup parent from repository -->
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.6.RELEASE</version>
            <relativePath/>
        </parent>
        <groupId>pers.huangyuhui</groupId>
        <artifactId>redis</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>springboot_redis</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>11</java.version>
        </properties>
    
        <dependencies>
            <!-- Web -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <!-- MyBatis -->
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.0.1</version>
            </dependency>
            <!-- Redis -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-redis</artifactId>
            </dependency>
            <!-- MySQL -->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
        </dependencies>
    
        <build>
            <!-- mvn package -->
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
    </project>
  3. SpringbootRedisApplication.java : Spring Boot启动类

    package pers.huangyuhui.redis;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    public class SpringbootRedisApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(SpringbootRedisApplication.class, args);
        }
    
    }
  4. application.properties : Spring Boot配置文件

    #JDBC-Connection Configuration Information
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true
    spring.datasource.username=xxxxxx
    spring.datasource.password=xxxxxx
    #Logging Configuration Information
    logging.level.pers.huangyuhui.redis=debug
  5. User.java : 用户信息实体类

    package pers.huangyuhui.redis.bean;
    
    /**
     * @project: springboot_redis
     * @description: 用户信息
     * @author: 黄宇辉
     * @date: 7/1/2019-7:08 AM
     * @version: 1.0
     * @website: https://yubuntu0109.github.io/
     */
    public class User {
    
        private Integer id;
        private String name;
        private String gender;
        private String email;
    
        //getter and setter
        ······
    }
  6. UserMapper.java : 操控用户数据表信息

    package pers.huangyuhui.redis.dao;
    
    import org.apache.ibatis.annotations.Mapper;
    import org.apache.ibatis.annotations.Select;
    import pers.huangyuhui.redis.bean.User;
    
    import java.util.List;
    
    /**
     * @project: springboot_redis
     * @description: Dao层-操控用户信息
     * @author: 黄宇辉
     * @date: 7/1/2019-7:12 AM
     * @version: 1.0
     * @website: https://yubuntu0109.github.io/
     */
    @Mapper
    public interface UserMapper {
    
        // TODO: 7/1/2019 查询所有用户信息
        @Select("select * from tb_user")
        List<User> selectAll();
    
        // TODO: 7/1/2019 根据id删除指定用户信息
        @Delete("Delete from tb_user where id = #{id}")
        void deleteById(Integer id);
    }
  7. UserService.java : 操控用户信息

    package pers.huangyuhui.redis.service;
    
    import pers.huangyuhui.redis.bean.User;
    
    import java.util.List;
    
    /**
     * @project: springboot_redis
     * @description: Service层-操控用户信息
     * @author: 黄宇辉
     * @date: 7/1/2019-7:25 AM
     * @version: 1.0
     * @website: https://yubuntu0109.github.io/
     */
    public interface UserService {
    
        // TODO: 7/1/2019 获取或有用户信息
        List<User> findAll();
    
         // TODO: 7/1/2019 根据id删除指定用户信息
        void delete(Integer id);
    }
  8. UserServiceImpl.java : UserService.java的实现类

    package pers.huangyuhui.redis.service.impl;
    
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;
    import pers.huangyuhui.redis.bean.User;
    import pers.huangyuhui.redis.dao.UserMapper;
    import pers.huangyuhui.redis.service.UserService;
    
    import javax.annotation.Resource;
    import java.util.List;
    
    /**
     * @project: springboot_redis
     * @description: UserService的实现类
     * @author: 黄宇辉
     * @date: 7/1/2019-7:27 AM
     * @version: 1.0
     * @website: https://yubuntu0109.github.io/
     */
    @Service
    @Transactional
    public class UserServiceImpl implements UserService {
    
        //注入Mapper对象
        @Resource
        private UserMapper userMapper;
    
        @Override
        public List<User> findAll() {
            return userMapper.selectAll();
        }
    
        @Override
        public void delete(Integer id) {
            userMapper.deleteById(id);
        }
    
    }
  9. UserController.java : 用户信息控制器

    package pers.huangyuhui.redis.controller;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    import pers.huangyuhui.redis.bean.User;
    import pers.huangyuhui.redis.service.UserService;
    
    import java.util.List;
    
    /**
     * @project: springboot_redis
     * @description: 用户控制器
     * @author: 黄宇辉
     * @date: 7/1/2019-7:28 AM
     * @version: 1.0
     * @website: https://yubuntu0109.github.io/
     */
    @Controller
    @RequestMapping("/user")
    public class UserController {
    
        //注入业务对象
        @Autowired
        private UserService userService;
    
        /**
         * @description: 获取所有用户信息
         * @date: 2019-07-01 8:16 AM
         * @return: java.util.List<pers.huangyuhui.redis.bean.User>
         */
        @RequestMapping("/getUserList")
        @ResponseBody
        public List<User> getUserList() { return userService.findAll(); }
    
        /**
         * @description: 删除指定id的好友信息
         * @param: id
         * @date: 2019-07-01 12:51 PM
         * @return: void
         */
        @RequestMapping("/deleteUser/{id}")
        public void deleteUser(@PathVariable Integer id) { userService.delete(id); }
    
    }
  10. userList.html : 用户信息列表页面 (将EasyUI框架的资源文件拷贝到src/main/resource下的static文件夹下,并在static文件夹中创建userList.html页面文件)

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>用户信息列表页面</title>
        <!-- CSS -->
        <link rel="stylesheet" type="text/css" href="easyui/themes/metro/easyui.css"/>
        <!-- JS -->
        <script type="text/javascript" src="easyui/jquery.min.js"></script>
        <script type="text/javascript" src="easyui/jquery.easyui.min.js"></script>
        <script type="text/javascript" src="easyui/themes/locale/easyui-lang-zh_CN.js"></script>
    
        <script type="text/javascript">
            $(function () {
                $('#graid').datagrid({
                    url: 'user/getUserList',
                    fit: true,
                    columns: [[
                        {field: 'id', title: '编号', width: 100},
                        {field: 'name', title: '姓名', width: 100},
                        {field: 'gender', title: '性别', width: 100},
                        {field: 'email', title: '邮箱', width: 200}
                    ]]
                });
            });
        </script>
    </head>
    <body>
    <!-- 用户信息列表 -->
    <table id="graid"></table>
    </body>
    </html>
  11. 启动Spring Boot项目,在浏览器中输入访问地址 : http://localhost:8080/userList.html后,显示效果参考下图 :

紧接着刷新页面三次,其控制台打印的日志信息如下所示,发现每刷新一次页面都会执行一次查询数据库操作,但如果将列表数据缓冲到Redis后,会发现控制台只会出现一次查询数据库的日志信息哟 !

2019-07-01 11:41:49.868 DEBUG 7844 --- [nio-8080-exec-3] p.h.redis.dao.UserMapper.selectAll       : ==>  Preparing: select * from tb_user 
2019-07-01 11:41:49.869 DEBUG 7844 --- [nio-8080-exec-3] p.h.redis.dao.UserMapper.selectAll       : ==> Parameters: 
2019-07-01 11:41:49.871 DEBUG 7844 --- [nio-8080-exec-3] p.h.redis.dao.UserMapper.selectAll       : <==      Total: 5

2019-07-01 11:41:54.250 DEBUG 7844 --- [nio-8080-exec-5] p.h.redis.dao.UserMapper.selectAll       : ==>  Preparing: select * from tb_user 
2019-07-01 11:41:54.250 DEBUG 7844 --- [nio-8080-exec-5] p.h.redis.dao.UserMapper.selectAll       : ==> Parameters: 
2019-07-01 11:41:54.253 DEBUG 7844 --- [nio-8080-exec-5] p.h.redis.dao.UserMapper.selectAll       : <==      Total: 5

2019-07-01 11:41:57.251 DEBUG 7844 --- [nio-8080-exec-7] p.h.redis.dao.UserMapper.selectAll       : ==>  Preparing: select * from tb_user 
2019-07-01 11:41:57.251 DEBUG 7844 --- [nio-8080-exec-7] p.h.redis.dao.UserMapper.selectAll       : ==> Parameters: 
2019-07-01 11:41:57.256 DEBUG 7844 --- [nio-8080-exec-7] p.h.redis.dao.UserMapper.selectAll       : <==      Total: 5

Process finished with exit code -1

Spring Boot集成Redis

Redis是一个完全开源的,遵守BSD协议的,内存中的数据结构存储,它既可以作为数据库,也可以作为缓存消息代理. 通常在企业中常将其作为缓存使用哟~ 接下来在Spring Boot集成MyBatis示例程序基础上将列表数据缓存到Redis中,详细步骤如下 :

  1. pom.xml中添加Spring Boot支持Redis的依赖

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-redis</artifactId>
    </dependency>
  2. SpringbootRedisApplication.java中添加@EnableCaching注解来开启缓存

    @SpringBootApplication
    @EnableCaching
    public class SpringbootRedisApplication {
        //······
    }
  3. 在业务逻辑类UserServiceImpl.java的方法上添加@Cacheable注解来支持Redis缓存

    @Override
    @Cacheable(value = "UserCatch", key = "'user.selectAll'")
    public List<User> findAll() {
        return userMapper.selectAll();
    }
  4. 为便于数据的传输,将实体类User.java实现序列化接口Serializable

    public class User implements Serializable {
        //······
    }
  5. application.properties中指定Redis缓存主机地址及端口号. 我使用的是Windows的Redis发行版哟,其学习笔记 : https://yubuntu0109.github.io/2019/06/25/Hi-Redis/

    #Redis Configuration Infromation
    spring.redis.host=localhost
    spring.redis.port=6379
  6. 启动Redis服务,并启动Spring Boot项目,在浏览器地址栏中输入访问地址 : http://localhost:8080/userList.html后,不断刷新页面,其控制台打印的日志信息如下,结论 : 在没有使用Redis缓存之前,每刷新一次页面,都会执行一次查询数据库的操作,添加缓存后,会发现日志信息中只出现了一次查询语句,这也就说明所配置的Redis缓存已经生效啦 ~

    2019-07-01 12:43:06.945  INFO 1984 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
    
    2019-07-01 12:43:06.946  INFO 1984 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
    
    2019-07-01 12:43:06.951  INFO 1984 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 5 ms
    
    2019-07-01 12:43:07.218  INFO 1984 --- [nio-8080-exec-7] io.lettuce.core.EpollProvider            : Starting without optional epoll library
    
    2019-07-01 12:43:07.218  INFO 1984 --- [nio-8080-exec-7] io.lettuce.core.KqueueProvider           : Starting without optional kqueue library
    
    2019-07-01 12:43:07.701  INFO 1984 --- [nio-8080-exec-7] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
    2019-07-01 12:43:07.791  INFO 1984 --- [nio-8080-exec-7] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
    
    2019-07-01 12:43:07.805 DEBUG 1984 --- [nio-8080-exec-7] p.h.redis.dao.UserMapper.selectAll       : ==>  Preparing: select * from tb_user 
    2019-07-01 12:43:07.815 DEBUG 1984 --- [nio-8080-exec-7] p.h.redis.dao.UserMapper.selectAll       : ==> Parameters: 
    2019-07-01 12:43:07.836 DEBUG 1984 --- [nio-8080-exec-7] p.h.redis.dao.UserMapper.selectAll       : <==      Total: 7
    
    
    Process finished with exit code -1

清除Redis缓存

当执行添加,更新和删除操作后,数据库中的数据会发生变化,继而Redis缓存中的数据同样也需要进行相应的变化,为了保证Redis缓存中的数据与数据库中的一致,通常需要在执行添加,更新删除操作之前清除缓存,然后再下一次执行查询操作时,将新的数据存储到Redis缓存中 .

若要实现清除缓存的功能,只需在相应的方法中使用@CacheEvict注解即可,下面以案例程序中的删除用户功能为例,在用户业务逻辑类的deleteUser()方法上添加@CacheEvict注解 :

@Override
@CacheEvict(value = "UserCatch", key = "'user.selectAll'")
public void delete(Integer id) {
    userMapper.deleteById(id);
}

重启Spring Boot项目,在浏览器地址栏中输入访问地址 : http://localhost:8080/user/deleteUser/5, ../6 , ../7删除id为5,6,7的用户信息后再查询用户列表信息 : http://localhost:8080/userList.html,其控制台打印的日志信息如下 :

2019-07-01 18:13:45.143 DEBUG 14764 --- [nio-8080-exec-1] p.h.redis.dao.UserMapper.deleteById      : ==>  Preparing: Delete from tb_user where id = ? 
2019-07-01 18:13:45.160 DEBUG 14764 --- [nio-8080-exec-1] p.h.redis.dao.UserMapper.deleteById      : ==> Parameters: 5(Integer)
2019-07-01 18:13:45.162 DEBUG 14764 --- [nio-8080-exec-1] p.h.redis.dao.UserMapper.deleteById      : <==    Updates: 1

2019-07-01 18:13:45.331  INFO 14764 --- [nio-8080-exec-1] io.lettuce.core.EpollProvider            : Starting without optional epoll library
2019-07-01 18:13:45.332  INFO 14764 --- [nio-8080-exec-1] io.lettuce.core.KqueueProvider           : Starting without optional kqueue library

2019-07-01 18:15:16.033 DEBUG 14764 --- [nio-8080-exec-4] p.h.redis.dao.UserMapper.deleteById      : ==>  Preparing: Delete from tb_user where id = ? 
2019-07-01 18:15:16.033 DEBUG 14764 --- [nio-8080-exec-4] p.h.redis.dao.UserMapper.deleteById      : ==> Parameters: 6(Integer)
2019-07-01 18:15:16.034 DEBUG 14764 --- [nio-8080-exec-4] p.h.redis.dao.UserMapper.deleteById      : <==    Updates: 1

2019-07-01 18:15:31.217 DEBUG 14764 --- [nio-8080-exec-6] p.h.redis.dao.UserMapper.deleteById      : ==>  Preparing: Delete from tb_user where id = ? 
2019-07-01 18:15:31.218 DEBUG 14764 --- [nio-8080-exec-6] p.h.redis.dao.UserMapper.deleteById      : ==> Parameters: 7(Integer)
2019-07-01 18:15:31.219 DEBUG 14764 --- [nio-8080-exec-6] p.h.redis.dao.UserMapper.deleteById      : <==    Updates: 1

2019-07-01 18:15:47.353 DEBUG 14764 --- [nio-8080-exec-4] p.h.redis.dao.UserMapper.selectAll       : ==>  Preparing: Select * from tb_user 
2019-07-01 18:15:47.353 DEBUG 14764 --- [nio-8080-exec-4] p.h.redis.dao.UserMapper.selectAll       : ==> Parameters: 
2019-07-01 18:15:47.377 DEBUG 14764 --- [nio-8080-exec-4] p.h.redis.dao.UserMapper.selectAll       : <==      Total: 4

Process finished with exit code -1

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