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
整合测试
1、导入 MyBatis 所需要的依赖
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
3、测试数据库是否连接成功！
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;
}
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<Department> getDepartments();
// 通过id获得部门
Department getDepartment(Integer id);
}
6、对应的Mapper映射文件
DepartmentMapper.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.kuang.mapper.DepartmentMapper">
<select id="getDepartments" resultType="Department">
select * from department;
</select>
<select id="getDepartment" resultType="Department" parameterType="int">
select * from department where id = #{id};
</select>
</mapper>
7、maven配置资源过滤问题
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
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<Department> getDepartments(){
return departmentMapper.getDepartments();
}
// 查询全部部门
@GetMapping("/getDepartment/{id}")
public Department getDepartment(@PathVariable("id") Integer id){
return departmentMapper.getDepartment(id);
}
}
启动项目访问进行测试！
我们增加一个员工类再测试下，为之后做准备
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
}
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<Employee> 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、编写 EmployeeMapper.xml 配置文件
<?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.kuang.mapper.EmployeeMapper">
<resultMap id="EmployeeMap" type="Employee">
<id property="id" column="eid"/>
<result property="lastName" column="last_name"/>
<result property="email" column="email"/>
<result property="gender" column="gender"/>
<result property="birth" column="birth"/>
<association property="eDepartment" javaType="Department">
<id property="id" column="did"/>
<result property="departmentName" column="dname"/>
</association>
</resultMap>
<select id="getEmployees" resultMap="EmployeeMap">
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
</select>
<insert id="save" parameterType="Employee">
insert into employee (last_name,email,gender,department,birth)
values (#{lastName},#{email},#{gender},#{department},#{birth});
</insert>
<select id="get" resultType="Employee">
select * from employee where id = #{id}
</select>
<delete id="delete" parameterType="int">
delete from employee where id = #{id}
</delete>
</mapper>
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<Employee> getEmployees(){
return employeeMapper.getEmployees();
}
@GetMapping("/save")
public int save(){
Employee employee = new Employee();
employee.setLastName("kuangshen");
employee.setEmail("qinjiang@qq.com");
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);
}
}
