SpringBoot

Posted 2021-09-06 Maggieq8324的博客

目录

• 前言
  • 环境
• 具体实现
  • 项目结构
  • 项目配置
  • 实现代码
  • 测试

前言

Mybatis是一个半自动化ORM（Object Relation Mapping）框架， 之所以说Mybatis半自动化，是因为SQL语句需要用户自定义，SQL的解析，执行等工作由Mybatis执行，这里记录下SpringBoot 整合Mybatis的案例。

环境

SpringBoot2.53 + Mybatis2.2.0

具体实现

项目结构

• 项目结构如下所示

项目配置

• pom.xml

<!-- web -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<!-- jdbc -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

<!-- mysql -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

<!-- mybatis -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.0</version>
</dependency>

<!-- lombok -->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>

• application.yml

spring:
  application:
    name: mybatis-learn
  # 文件编码 UTF8
  mandatory-file-encoding: UTF-8
  # 数据源配置，请修改为你项目的实际配置
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/cms?useSSL=false&serverTimezone=UTC&characterEncoding=UTF8
    username: root
    password: sunday

# mybatis配置（顶头开始写，否则读取不到）
mybatis:
  # mapper路径位置
  mapper-locations: classpath:mapper/*.xml
  configuration:
    # 开启下划线转驼峰
    map-underscore-to-camel-case: true

server:
  port: 8083

• Table

CREATE TABLE `product` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `title` varchar(100) COLLATE utf8_unicode_ci DEFAULT NULL,
  `create_time` datetime DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

实现代码

• 启动类

@SpringBootApplication
@MapperScan(basePackages = {"com.coisini.mybatislearn.mapper"}) // 扫描的mapper
public class MybatisLearnApplication {

    public static void main(String[] args) {
        SpringApplication.run(MybatisLearnApplication.class, args);
    }

}

• ProductController.java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

@RequestMapping("/product")
@RestController
public class ProductController {

    @Autowired
    private ProductService productService;

    /**
     * 查询Products
     * @return
     */
    @GetMapping("/select")
    public List<Product> selectProducts() {
        return productService.getProducts();
    }

	/**
     * 查询Products
     * @return
     */
    @GetMapping("/select1")
    public List<Product> getProducts1() {
        return productService.getProducts1();
    }

    /**
     * 插入product
     * @return
     */
    @GetMapping("/insert")
    public long insertProduct() {
        return productService.insertProduct();
    }

}

• ProductService.java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;

@Service
public class ProductService {

    @Autowired
    private ProductMapper productMapper;

    /**
     * 查询products
     * @return
     */
    public List<Product> getProducts() {
        return productMapper.getProducts();
    }

	/**
     * 查询products
     * @return
     */
    public List<Product> getProducts1() {
        return productMapper.getProducts1();
    }

    /**
     * 插入product
     * @return
     */
    public long insertProduct() {
        Product product = new Product();
        product.setTitle("NewProduct");

        productMapper.insertProduct(product);
        return product.getId();
    }
}

• ProductMapper.java

import org.springframework.stereotype.Repository;
import java.util.List;

@Repository
public interface ProductMapper {

    /**
     * 查询products
     * @return
     */
    List<Product> getProducts();

	/**
     * 查询products
     * 注解编写sql
     * @return
     */
    @Select("select * from product")
    List<Product> getProducts1();

    /**
     * 插入product
     * @param product
     * @return
     */
    long insertProduct(Product product);

}

• Product.java

import lombok.Getter;
import lombok.Setter;
import java.util.Date;

@Getter
@Setter
public class Product {

    private Integer id;

    private String title;

    private Date createTime;

}

• ProductMapper.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="com.coisini.mybatislearn.mapper.ProductMapper">
    <resultMap id="BaseResultMap" type="com.coisini.mybatislearn.model.Product">
        <id column="id" property="id"/>
        <result column="title" property="title"/>
        <result column="create_time" property="createTime"/>
    </resultMap>

    <select id="getProducts" resultMap="BaseResultMap">
        select * from product
    </select>

	<!-- useGeneratedKeys="true" 通过jdbc getGeneratedKeys方法获取主键 -->
	<!-- keyProperty="id" 映射到resultMap id 属性上 -->
    <insert id="insertProduct" useGeneratedKeys="true" keyProperty="id"
            parameterType="com.coisini.mybatislearn.model.Product">
        INSERT INTO product(title) VALUES (#{title})
    </insert>
</mapper>

• 注意事项：

1.mapper-namespace需要与Mapper接口对应
2.mapper接口文件名最好与Mybatis的映射文件名一样
2.标签中的id必须与mapper接口中的方法名一致

测试

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作者：Maggieq8324

出处：https://www.cnblogs.com/maggieq8324/

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