10、整合MyBatis

• 官方文档：http://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/

• Maven仓库地址：https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter/2.1.1

一、整合步骤

1.1、导入 MyBatis 所需要的依赖

    org.mybatis.spring.boot
    mybatis-spring-boot-starter
    2.1.1

1.2、配置数据库连接信息（不变）

spring:
  datasource:
    username: root
    password: 123456
    #?serverTimezone=UTC解决时区的报错
    url: jdbc:mysql://localhost:3306/springboot?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

    #Spring Boot 默认是不注入这些属性值的，需要自己绑定
    #druid 数据源专有配置
    initialSize: 5
    minIdle: 5
    maxActive: 20
    maxWait: 60000
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true

    #配置监控统计拦截的filters，stat:监控统计、log4j：日志记录、wall：防御sql注入
    #如果允许时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority
    #则导入 log4j 依赖即可，Maven 地址：https://mvnrepository.com/artifact/log4j/log4j
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

1.3、测试数据库连接

1.4、创建实体类，导入 Lombok！

• Department.java

package com.kuang.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Department {

    private Integer id;
    private String departmentName;

}

1.5、创建mapper目录以及对应的 Mapper 接口

• DepartmentMapper.java

//@Mapper : 表示本类是一个 MyBatis 的 Mapper
@Mapper
@Repository
public interface DepartmentMapper {

    // 获取所有部门信息
    List getDepartments();

    // 通过id获得部门
    Department getDepartment(Integer id);

}

1.6、对应的Mapper映射文件

• DepartmentMapper.xml

    
       select * from department;
    

    
       select * from department where id = #{id};
    

1.7、maven配置资源过滤问题

    
        src/main/java
        
            **/*.xml
        
        true
    

1.8、编写部门的 DepartmentController 进行测试！**

@RestController
public class DepartmentController {
    
    @Autowired
    DepartmentMapper departmentMapper;
    
    // 查询全部部门
    @GetMapping("/getDepartments")
    public List getDepartments(){
        return departmentMapper.getDepartments();
    }

    // 查询全部部门
    @GetMapping("/getDepartment/{id}")
    public Department getDepartment(@PathVariable("id") Integer id){
        return departmentMapper.getDepartment(id);
    }
    
}

三、 案例二

3.1、新建一个pojo类 Employee ；

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Employee {

    private Integer id;
    private String lastName;
    private String email;
    //1 male, 0 female
    private Integer gender;
    private Integer department;
    private Date birth;

    private Department eDepartment; // 冗余设计

}

3.2、新建一个 EmployeeMapper 接口

//@Mapper : 表示本类是一个 MyBatis 的 Mapper
@Mapper
@Repository
public interface EmployeeMapper {

    // 获取所有员工信息
    List getEmployees();

    // 新增一个员工
    int save(Employee employee);

    // 通过id获得员工信息
    Employee get(Integer id);

    // 通过id删除员工
    int delete(Integer id);

}

3.3、编写 EmployeeMapper.xml 配置文件

    
        
        
        
        
        
        
            
            
        
    

    
        select e.id as eid,last_name,email,gender,birth,d.id as did,d.department_name as dname
        from department d,employee e
        where d.id = e.department
    

    
        insert into employee (last_name,email,gender,department,birth)
        values (#{lastName},#{email},#{gender},#{department},#{birth});
    

    
        select * from employee where id = #{id}
    

    
        delete from employee where id = #{id}
    

3.4、编写EmployeeController类进行测试

@RestController
public class EmployeeController {

    @Autowired
    EmployeeMapper employeeMapper;

    // 获取所有员工信息
    @GetMapping("/getEmployees")
    public List getEmployees(){
        return employeeMapper.getEmployees();
    }

    @GetMapping("/save")
    public int save(){
        Employee employee = new Employee();
        employee.setLastName("kuangshen");
        employee.setEmail("[email protected]");
        employee.setGender(1);
        employee.setDepartment(101);
        employee.setBirth(new Date());
        return employeeMapper.save(employee);
    }

    // 通过id获得员工信息
    @GetMapping("/get/{id}")
    public Employee get(@PathVariable("id") Integer id){
        return employeeMapper.get(id);
    }

    // 通过id删除员工
    @GetMapping("/delete/{id}")
    public int delete(@PathVariable("id") Integer id){
        return employeeMapper.delete(id);
    }

}

测试结果完成，搞定收工！