SpringBoot 整合 MybatisPlus (项目的创建及简单的单表查询)
2024-09-05 22:21:35
添加依赖
<!--mybatis-plus的springboot支持-->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.0.5</version>
</dependency>
<!--mysql驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
创建数据库和表
CREATE TABLE `user` (`id` BIGINT(20) not null AUTO_INCREMENT comment '主键ID',
`name` VARCHAR(30) DEFAULT null comment '姓名',
`age` int(11) DEFAULT null comment '年龄',
`email` VARCHAR(50) DEFAULT null comment '邮箱',
PRIMARY KEY (`id`)
) ENGINE=INNODB DEFAULT CHARSET=utf8;
insert into user (id,name,age,email) VALUES ('1','Jone','18','test1@qq.com');
insert into user (id,name,age,email) VALUES ('2','Jack','20','test2@qq.com');
insert into user (id,name,age,email) VALUES ('3','Tom','28','test3@qq.com');
insert into user (id,name,age,email) VALUES ('4','Sandy','21','test4@qq.com');
insert into user (id,name,age,email) VALUES ('5','Billie','24','test5@qq.com');
配置 application.yml
spring:
application:
name: spring-boot-mybatis-plus
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/mysqlName?useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true&useSSL=false
username: root
password: root
创建pojo类
public class User {
@TableId(value = "ID",type = IdType.AUTO) //设置id为自增长
private Long id;
private String name;
private Integer age;
private String email;
//( set,get,toString方法自行添加 )
}
创建 UserMapper接口
public interface UserMapper extends BaseMapper<User> {
}
注意：BaseMapper接口引入的包是
com.baomidou.mybatisplus.core.mapper.BaseMapper
编写 SpringBoot 启动类
@MapperScan("cn.mybatisplus.mapper")
@SpringBootApplication
public class MyApplication {
public static void main(String[] args) {
SpringApplication.run(MyApplication.class,args);
}
}
@MapperScan("cn.mybatisplus.mapper"). 扫描 mapper 包
编写测试代码
@SpringBootTest
@RunWith(SpringRunner.class)
public class UserMapperTest {
@Autowired
private UserMapper userMapper;
@Test
public void testList(){
List<User> users = this.userMapper.selectList(null);
for (User user: users) {
System.out.println(user);
}
}
@Test
public void testSelectById(){
User user = this.userMapper.selectById(3L); //根据id查数据
System.out.println(user);
}
@Test
public void testSelectByLike(){
QueryWrapper<User> wrapper = new QueryWrapper<>();
wrapper.like("name","o"); //查询 name字段中包含‘o’的数据
List<User> users = this.userMapper.selectList(wrapper);//返回值是一个list集合
for (User u : users) {
System.out.println(u);
}
}
@Test
public void testSelectByLe(){
QueryWrapper<User> wrapper = new QueryWrapper<>();
/**
* eq : 等于
* ne : 不等于
* gt : 大于
* ge : 大于等于
* lt : 小于
* le : 小于等于
* 更多查看 https://mp.baomidou.com/guide/wrapper.html#abstractwrapper
*/
wrapper.le("age","20"); //设置年龄小于等于20
List<User> users = this.userMapper.selectList(wrapper);
for (User u : users) {
System.out.println(u);
}
}
@Test
public void testSave() {
User user = new User();
user.setAge(25);
user.setEmail("zhangsan@qq.com");
user.setName("zhangsan");
int count = this.userMapper.insert(user);
System.out.println("新增数据成功 count ==> "+count);
}
@Test
public void testDelete(){
this.userMapper.deleteById(6L);
System.out.println("删除成功");
}
@Test
public void testUpdate(){
User user = new User();
user.setId(5L);
user.setName("Lisi");
int i = this.userMapper.updateById(user);
System.out.println(" 有"+i+"条数据被修改");
}
}
分页查询
需要增加分页插件配置（这里就简单在启动类加 Bean）
@MapperScan("cn.itcast.mybatisplus.mapper")
@SpringBootApplication
public class MyApplication {
/*
* 分页插件
*/
@Bean
public PaginationInterceptor paginationInterceptor(){
return new PaginationInterceptor();
}
public static void main(String[] args) {
SpringApplication.run(MyApplication.class,args);
}
}
测试
@Test
public void testSelectPage() {
Page<User> page = new Page<>(2, 2);
IPage<User> userIPage = this.userMapper.selectPage(page, null);
System.out.println("总页数 ----> " + userIPage.getTotal());
System.out.println("当前页数 ----> " + userIPage.getCurrent());
System.out.println("当前每页显示数 ----> " + userIPage.getSize());
List<User> records = userIPage.getRecords();
for (User u: records) {
System.out.println(u);
}
}
运行结果
总页数 ----> 5
当前页数 ----> 2
当前每页显示数 ----> 2
User(id=3, name=Tom, age=28, email=test3@qq.com)
User(id=4, name=Sandy, age=21, email=test4@qq.com)
最新文章
- cocos2d-x 3.10 屏幕适配问题
- C#基础---扩展方法的应用
- 彻底卸载sublime txt
- 强、软、弱、虚引用,ReferenceQueue,WeakHashMap
- 问题：glGenBuffers()函数没有定义怎么办
- Hadoop 学习笔记（一） HDFS API
- 转：ASCII码表_全_完整版
- UVALive 4123 Glenbow Museum (组合数学)
- zoj 3822 Domination (可能性DP)
- python——时间与时间戳之间的转换
- VB 用代码创建的控件和接收事件
- java数据类型易错点简单总结，欢迎大神前辈补充！谢谢
- URLSearchParams 接口
- inventory file 与hosts patterns （ansible 机器清单 与 主机匹配模式)
- spring-boot json数据交互
- SpringMVC源码解读 - HandlerMapping - RequestMappingHandlerMapping请求分发
- tomcat多实例方案启动脚本
- spring boot 与 自定义interceptor
- JavaScript 循环语句入门详解
- Kafka vs RocketMQ—— Topic数量对单机性能的影响