1.简介
MyBatis-Plus(简称 MP)是一个 MyBatis 的增强工具,在 MyBatis 的基础上只做增强不做改变,为简化开发、提高效率而生
官网:https://mybatis.plus/
2.搭建环境
2.1pom.xml配置
com.baomidou
mybatis-plus
3.3.2
org.springframework
spring-context
5.1.6.RELEASE
org.springframework
spring-jdbc
5.1.6.RELEASE
org.springframework
spring-orm
5.1.6.RELEASE
com.alibaba
druid
1.1.21
mysql
mysql-connector-java
runtime
5.1.47
junit
junit
4.12
test
com.github.pagehelper
pagehelper
5.1.8
2.2spring配置
2.3mybatis配置
实体配置
//@TableName 注解,帮助mybatis与数据库表关联
@TableName("t_departments")
public class Department {
@TableId(value = "id",type = IdType.AUTO)//指定自增策略
private Integer id;
private String name;
private String location;
}
3.案例
3.1插入
/**
* 测试,mybatisplus的插入功能
*/
@Test
public void testInsert() {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
//调用mybatisplus的插入方法
departmentMapper.insert(new Department(null, "人事部", "杭州"));
}
3.2修改
/**
* 根据 ID 修改
*/
@Test
public void testupdateById() {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
Department d = new Department();
d.setId(15);
d.setName("abc");
d.setLocation("abc");
departmentMapper.updateById(d);
}
/**
* 根据 whereEntity 条件,更新记录
*
* 实体对象 (set 条件值,可以为 null)
* 实体对象封装操作类(可以为 null,里面的 entity 用于生成 where 语句)
*/
@Test
public void testupdate() {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
Department d = new Department();
d.setId(16);
d.setName("123");
d.setLocation("123");
departmentMapper.update(d,new UpdateWrapper()
.eq("name","abc")
.eq("location","abc"));
}
3.3删除
@Test
public void testDeleteByMap(){
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
Map map = new HashMap<>();
map.put("id",11);
map.put("name","人事部");
departmentMapper.deleteByMap(map);
}
/**
* 根据 entity 条件,删除记录
*
* 实体对象封装操作类(可以为 null)
*/
@Test
public void testDelete() {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
departmentMapper.delete(new QueryWrapper().eq("id",12));
}
/**
* 删除多条数据
* 传入参数为collection
*/
@Test
public void testdeleteBatchIds() {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
departmentMapper.deleteBatchIds(Arrays.asList(10,13,14));
}
3.4查询
/**
* 根据 ID 查询
*
* id 主键ID
*/
@Test
public void testselectById(){
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
Department department = departmentMapper.selectById(1);
System.out.println(department);
}
/**
* 查询(根据ID 批量查询)
*
* 主键ID列表(不能为 null 以及 empty)
*/
@Test
public void testselectBatchIds(){
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
List list = departmentMapper.selectBatchIds(Arrays.asList(1,2,15));
for (Department department : list) {
System.out.println(department);
}
}
/**
* 查询(根据 columnMap 条件)
*
* 表字段 map 对象
*/
@Test
public void testselectByMap(){
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
Map map = new HashMap();
map.put("name","研发部");
map.put("location","上海");
List list = departmentMapper.selectByMap(map);
for (Department department : list) {
System.out.println(department);
}
}
/**
* 根据 entity 条件,查询一条记录
* 实体对象封装操作类(可以为 null)
*/
@Test
public void testselectOne(){
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
Department department = departmentMapper.selectOne(new QueryWrapper().gt("id",10));
System.out.println(department);
}
/**
* 根据 Wrapper 条件,查询总记录数
* 实体对象封装操作类(可以为 null)
*/
@Test
public void testselectCount(){
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
int count = departmentMapper.selectCount(null);
System.out.println(count);
}
/**
* 根据 entity 条件,查询全部记录
*
* 实体对象封装操作类(可以为 null)
*/
@Test
public void testselectList(){
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
List list = departmentMapper.selectList(null);
for (Department department : list) {
System.out.println(department);
}
}
/**
* 根据 Wrapper 条件,查询全部记录
*
* 实体对象封装操作类(可以为 null)
*/
@Test
public void testselectMaps(){
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
DepartmentMapper departmentMapper = applicationContext.getBean("departmentMapper", DepartmentMapper.class);
List