SpringBoot整合Mybatis

2019-11-24 本文已影响0人 ip小怪兽

$\color{red}{本项目开发环境}$

JDK 1.8
Maven 3.6.0
Spring Boot 2.2.1
IDEA 2019.1.3
pageHelper 物理分页插件

$\color{blue}{待添加额外功能}$

Swagger2
构建与前端交互的通用RESTful API 【JsonResponse】

步骤：

创建一个Spring Boot工程

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配置工程结构及JDK版本

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选择起步依赖

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查看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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <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>2.1.1</version>
        </dependency>
        <!--MyBatis分页插件-->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.10</version>
        </dependency>
        <!--MySQL驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--阿里巴巴Druid数据库连接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.17</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

配置application.properties

#数据库配置
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
#Druid连接池配置
# 初始化大小
spring.datasource.druid.initial-size=3
#最小连接数
spring.datasource.druid.min-idle=3
#最大连接数
spring.datasource.druid.max-active=10
#连接超时时间
spring.datasource.druid.max-wait=60000
#Mybatis配置
mybatis.mapper-locations=classpath:mapper/*Mapper.xml
#日志打印（控制台显示SQL语句）
logging.level.com.example.demo.apply.mapper=debug

创建数据库表

DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`(
`id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'id',
`username` varchar(50) DEFAULT NULL COMMENT '用户名',
`password` varchar(50) DEFAULT NULL COMMENT '密码',
`truename` varchar(50) DEFAULT NULL COMMENT '邮箱',
PRIMARY KEY (`id`)
)ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

INSERT INTO `user`(`username`,`password`,`truename`) VALUES('lishimin','123456','李世民'),('yuefei','123123','岳飞'),('lixunhuan','123456','李寻欢');

创建实体类User.Java

package com.example.demo.apply.entity;

import lombok.Data;

/**
 * ClassName: com.example.demo.apply.entity.User <br/>
 * Description: User实体<br/>
 */
@Data
public class User {

    /**
     * id
     */
    private Long id;

    /**
     * 用户名
     */
    private String username;

    /**
     * 密码
     */
    private String password;

    /**
     * 别名
     */
    private String truename;
}

注意：这里使用了Lombok来简化代码

创建UserMapper.java接口

package com.example.demo.apply.mapper;

import com.example.demo.apply.entity.User;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

/**
 * ClassName: com.example.demo.apply.mapper.UserMapper <br/>
 * Description: <br/>
 */
@Mapper
public interface UserMapper {

    /**
     * 获取所有的User
     *
     * @return 返回所有的User
     */
    List<User> listUsers();
}

在src/main/resource包下创建mapper包，并将创建的Mapper文件存放在该包下

<?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="com.example.demo.apply.mapper.UserMapper">

    <select id="listUsers" resultType="com.example.demo.apply.entity.User">
        select * from user
    </select>
    
</mapper>

注意：该UserMapper.xml文件对应UserMapper.java接口

创建service层IUserService.java接口

package com.example.demo.apply.service;

import com.example.demo.apply.entity.User;
import com.github.pagehelper.PageInfo;

import java.util.List;

/**
 * ClassName: com.example.demo.apply.service.UserService <br/>
 * Description: <br/>
 */
public interface IUserService {

    /**
     * 查询所有User，不带分页
     *
     * @return 返回Users
     */
    List<User> listUsers();

    /**
     * 查询所有User，带分页
     *
     * @param pageNum  当前页数
     * @param pageSize 每页数量
     * @return 返回Users
     */
    PageInfo<User> listUsersWithPage(int pageNum, int pageSize);

}

service层的实现类UserServiceImpl.java

package com.example.demo.apply.service.impl;

import com.example.demo.apply.entity.User;
import com.example.demo.apply.mapper.UserMapper;
import com.example.demo.apply.service.IUserService;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

/**
 * ClassName: com.example.demo.apply.service.impl.UserServiceImpl <br/>
 * Description: <br/>
 */
@Service
public class UserServiceImpl implements IUserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public List<User> listUsers() {
        return userMapper.listUsers();
    }

    @Override
    public PageInfo<User> listUsersWithPage(int pageNum, int pageSize) {
        PageHelper.startPage(pageNum, pageSize);
        List<User> users = userMapper.listUsers();
        PageInfo<User> pageInfo = PageInfo.of(users);
        return pageInfo;
    }
}

创建web层UserController.java

package com.example.demo.apply.web;

import com.example.demo.apply.entity.User;
import com.example.demo.apply.mapper.UserMapper;
import com.example.demo.apply.service.IUserService;
import com.github.pagehelper.PageInfo;
import org.apache.ibatis.annotations.Param;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

/**
 * ClassName: com.example.demo.apply.web.UserController <br/>
 * Description: <br/>
 *
 * @author lhp <br/>
 * @date 2019/11/24 14:29 <br/>
 */
@RestController
@RequestMapping("/userController")
public class UserController {

    @Autowired
    private IUserService userService;

    /**
     * 查询所有User信息，不带分页
     *
     * @return 返回所有Users
     */
    @GetMapping("/findAll")
    public List<User> findAll() {
        return userService.listUsers();
    }

    /**
     * 查询所有User信息，带分页
     *
     * @param pageNum  当前页数
     * @param pageSize 每页数量
     * @return 所有Users
     */
    @PostMapping("/findAllWithPage")
    public PageInfo<User> findAllWithPage(@RequestParam int pageNum,
                                          @RequestParam int pageSize) {
        return userService.listUsersWithPage(pageNum, pageSize);
    }

}

用postman测试接口地址

不带分页查询
带分页查询

14.总结
Spring Boot项目可以很容易地整合Mybatis框架，只需要在pom中引入相关的起步依赖，并经过简单的配置就可以快速使用了。

SpringBoot整合Mybatis

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