MybatisPlus入门程序

CREATE DATABASE `mybatisplus`
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 USE `mybatisplus`
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 CREATE TABLE `user`(
     id BIGINT(20) NOT NULL COMMENT ‘主键ID‘,
     NAME VARCHAR(30) NULL DEFAULT NULL COMMENT ‘姓名‘,
     age INT(11) NULL DEFAULT NULL COMMENT ‘年龄‘,
     email VARCHAR(50) NULL DEFAULT NULL COMMENT ‘邮箱‘,
     PRIMARY KEY (id)
 );
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 DELETE FROM USER;
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 INSERT INTO USER (id, NAME, age, email) VALUES
 (1, ‘Jone‘, 18, ‘test1@baomidou.com‘),
 (2, ‘Jack‘, 20, ‘test2@baomidou.com‘),
 (3, ‘Tom‘, 28, ‘test3@baomidou.com‘),
 (4, ‘Sandy‘, 21, ‘test4@baomidou.com‘),
 (5, ‘Billie‘, 24, ‘test5@baomidou.com‘);

<dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
 </dependency>

<dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
     <version>1.18.12</version>
     <optional>true</optional>
 </dependency>

<dependency>
     <groupId>com.baomidou</groupId>
     <artifactId>mybatis-plus-boot-starter</artifactId>
     <version>3.0.5</version>
 </dependency>

# mysql
 spring.datasource.username=root
 spring.datasource.password=123456
 spring.datasource.url=jdbc:mysql://localhost:3306/mybatisplus?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8
 # 东8时区，serverTimezone=GMT%2B8
 spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
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 # 配置日志,方便查看SQL语句
 mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

package com.zy.pojo;
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 import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.NoArgsConstructor;
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 @Data
 @AllArgsConstructor
 @NoArgsConstructor
 public class User {
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     private Long id;
     private String name;
     private Integer age;
     private String email;
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 }

package com.zy.mapper;
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 import com.baomidou.mybatisplus.core.mapper.BaseMapper;
 import com.zy.pojo.User;
 import org.springframework.stereotype.Repository;
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 @Repository //代表持久层
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 //在对应的mapper上面 继承 基本的接口BaseMapper
 public interface UserMapper extends BaseMapper<User> {
     //继承之后，所有的CRUD就完成了
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 }

 
package com.zy;
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 import org.mybatis.spring.annotation.MapperScan;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
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 //扫描mapper文件夹
 @MapperScan("com.zy.mapper")
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 @SpringBootApplication
 public class DemoApplication {
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     public static void main(String[] args) {
         SpringApplication.run(DemoApplication.class, args);
     }
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 }

@Test
 public void select(){
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     //查询全部用户
     List<User> users = userMapper.selectList(null);
     users.forEach(System.out::println);
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 }