SpringBoot——SpringBoot整合MyBatis(注解、XML配置)

待我称王封你为后i 2023-05-22 12:30 28阅读 0赞

## 目录 ##

*  一、SpringBoot整合MyBatis
 *  二、Mybatis增删改查(使用注解方式)
 *  三、Mybatis增删改查(XML配置方式)

![在这里插入图片描述][20200325204547571.png]

--------------------

# 一、SpringBoot整合MyBatis #

跳转到目录

#### 引入依赖 ####

<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>2.1.2</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.20</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </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>

依赖关系  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3OTg5OTgw_size_16_color_FFFFFF_t_70]

## 项目构建 ##

1、在resources下创建`department.sql`和`employee.sql`，项目启动时创建表(在数据库中自动生成)

schema:
      - classpath:sql/department.sql
      - classpath:sql/employee.sql

2、实体类

public class Department { 
        private Integer id;
        private String departmentName;
     
     	// 省略 getter/setter 方法
    }

public class Employee { 
        private Integer id;
        private String lastName;
        private Integer gender;
        private String email;
        private Integer dId;
        
        // 省略 getter/setter 方法
    }

3、配置文件

spring:
      datasource:
        username: root
        password: 1111
        url: jdbc:mysql://localhost:3306/springboot_mybatis
        driver-class-name: com.mysql.jdbc.Driver
        initialization-mode: always
        # 数据源更改为druid
        type: com.alibaba.druid.pool.DruidDataSource
    
        druid:
          # 连接池配置
          # 配置初始化大小、最小、最大
          initial-size: 1
          min-idle: 1
          max-active: 20
          # 配置获取连接等待超时的时间
          max-wait: 3000
          validation-query: SELECT 1 FROM DUAL
          test-on-borrow: false
          test-on-return: false
          test-while-idle: true
          pool-prepared-statements: true
          time-between-eviction-runs-millis: 60000
          min-evictable-idle-time-millis: 300000
          filters: stat,wall,slf4j
          # 配置web监控,默认配置也和下面相同(除用户名密码，enabled默认false外)，其他可以不配
          web-stat-filter:
            enabled: true
            url-pattern: /*
            exclusions: "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*"
          stat-view-servlet:
            enabled: true
            url-pattern: /druid/*
            login-username: admin
            login-password: root
            allow: 127.0.0.1
    
        schema:
          - classpath:sql/department.sql
          - classpath:sql/employee.sql

# 二、Mybatis增删改查(使用注解方式) #

跳转到目录

*  创建`mapper`接口

/** * Description: * * @author zygui * @date 2020/4/17 16:10 */
    // 指定这是一个操作数据库的mapper
    @Mapper // 这里必须要添加这个Mapper注解; 也可以在主启动类上统一通过@MapperScan(value="con.zy.mapper")来扫描
    public interface DepartmentMapper { 
    
        @Select("SELECT * FROM department WHERE id = #{id}")
        public Department getDeptById(@Param("id") Integer id);
    
        @Delete("DELETE FROM department WHERE id = #{id}")
        public int deleteDeptById(@Param("id") Integer id);
    
        @Options(useGeneratedKeys = true, keyProperty = "id")
        @Insert("INSERT INTO department(department_name) VALUES(#{departmentName})")
        public int insertDept(Department department);
    
        @Update("UPDATE department SET department_name = #{departmentName} WHERE id = #{id}")
        public int updateDept(Department department);
    }

*  创建`Controller`

@RestController
    public class DeptController { 
    
        @Resource
        private DepartmentMapper departmentMapper;
    
        @GetMapping("/dept/{id}")
        public Department getDepartment(@PathVariable("id") Integer id) { 
            return departmentMapper.getDeptById(id);
        }
    
        @GetMapping("/dept")
        public Department insertDept(Department department) { 
            int count = departmentMapper.insertDept(department);
            if (count > 0) { 
                System.out.println("插入数据成功");
            }
            return department;
        }

*  访问：`http://localhost:8080/dept?departmentName=gzy` 添加一条数据
    
    访问：`http://localhost:8080/dept/1`获取数据

## Mybatis配置 ##

开启`驼峰命名法`

我们的实体类和表中的列名一致，一点问题也没有

我们把department表的departmentName列名改为department\_name看看会发生什么

访问：http://localhost:8080/dept/1获取数据

> \[\{“id”:1,“departmentName”:null\}\]

由于列表和属性名不一致，所以就没有封装进去，我们表中的列名和实体类属性名都是遵循驼峰命名规则的，可以开启mybatis的开启驼峰命名配置

# 开启驼峰映射
    mybatis:
      configuration:
        map-underscore-to-camel-case: true

然后重启项目，重新插入数据，再查询就发现可以封装进去了

也可以通过向spring容器中注入org.mybatis.spring.boot.autoconfigure.ConfigurationCustomizer的方法设置mybatis参数

@org.springframework.context.annotation.Configuration
    public class MyBatisConfig { 
    
        @Bean
        public ConfigurationCustomizer configurationCustomizer(){ 
            return new ConfigurationCustomizer() { 
                @Override
                public void customize(Configuration configuration) { 
                    // 开启驼峰命名映射
                    configuration.setMapUnderscoreToCamelCase(true);
                }
            };
        }
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3OTg5OTgw_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3OTg5OTgw_size_16_color_FFFFFF_t_70 2]

## Mapper扫描 ##

使用`@mapper`注解的类可以被扫描到容器中，但是每个Mapper都要加上这个注解就是一个繁琐的工作，能不能直接扫描某个包下的所有Mapper接口呢，当然可以，在springboot启动类上加上`@MapperScan`

> @MapperScan(“cn.clboy.springbootmybatis.mapper”)

# 三、Mybatis增删改查(XML配置方式) #

跳转到目录

*  创建mybatis全局配置文件

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
    
        
        <settings>
            <setting name="mapUnderscoreToCamelCase" value="true"/>
        </settings>
    </configuration>

*  创建EmployeeMapper接口

@Mapper 或者 @MapperScan将接口扫描装配到容器中
    public interface EmployeeMapper { 
    
        public Employee getEmpById(@Param("id") Integer id);
    
        public void insertEmp(Employee employee);
    }

*  创建EmployeeMapper.xml映射文件

<?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.zy.mapper.EmployeeMapper">
    
        <select id="getEmpById" resultType="com.zy.pojo.Employee">
            SELECT * FROM employee WHERE id = #{id};
        </select>
    
        <insert id="insertEmp">
            INSERT INTO employee (lastName, email, gender, d_id) VALUSE (#{lastName}, #{email}, #{gender}, #{dId})
        </insert>
    </mapper>

*  配置文件(application.yaml)中指定配置文件和映射文件的位置

# 加载mybati的全局配置文件
    mybatis:
      config-location: classpath:mybatis/mybatis-config.xml
      mapper-locations: classpath:mybatis/mapper/*.xml

*  Controller

@RestController
    public class EmpController { 
    	@Resource
        private EmployeeMapper employeeMapper;
    
        @GetMapping("/emp/{id}")
        public Employee getEmp(@PathVariable("id") Integer id) { 
            return employeeMapper.getEmpById(id);
        }
    }

*  测试  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3OTg5OTgw_size_16_color_FFFFFF_t_70 3]

[20200325204547571.png]: /images/20230521/bd89df0fe12c43628410a40445d98b0f.png
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