六、MybatisPlus快速上手 数据库操作
注意！注意！注意！springboot版本选择2.7.2
1.ORM介绍（对象关系映射）
既包含存储，又包含映射。将java类映射到数据库
2.MybatisPlus介绍
ORM框架
数据库操作来啦！注意欧
1.添加依赖到pom。xmlwen文件中
<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.2</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId><version>1.1.20</version></dependency>2.在properties中加入配置
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/Englishword?useSSL=false
spring.datasource.username=root
spring.datasource.password="youpassword"
3.在mysql中添加数据库和表单，我添加了Englisword database 和user table
有关MYSQL的具体操作大家可以参考
CREATE TABLE user (id VARCHAR(50) PRIMARY KEY,username VARCHAR(50) NOT NULL,password VARCHAR(50) NOT NULL,birth VARCHAR(50) NOT NULL
);
INSERT INTO user (id, username, password, birthday)
VALUES ('1', 'Alice', 'password123', '1990-01-01'), ('2', 'Bob', '123password', '1995-05-10');
4.在启动类里面添加@MapperScan（“mapper文件夹路径”）
5.package mapper 添加usermapper （记得导入user类）
package com.example.sql2.mapper;
import com.example.sql2.entity.user;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import org.springframework.stereotype.Repository;import java.util.List;
@Repository
@Mapper
public interface UserMapper {//根据ID查找用户/* @Select("select * from user where id=#{id})public int findbyid(int id);*///查询所有用户@Select("select * from user")public List<user> find();//增加用户@Insert("insert into user values(#{id},#{username},#{password},#{birthday})")public int insert(user user);//更新用户@Update("update user set username=#{username},password=#{password},#{birthday}) where id=#{id}")public int update(user user);}
6.package entity添加实体user、
package com.example.sql2.entity;public class user {private String id;private String username;private String password;private String birthday;@Overridepublic String toString() {return "user{" +"id='" + id + '\'' +", username='" + username + '\'' +", password='" + password + '\'' +", birthday='" + birthday + '\'' +'}';}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getBirthday() {return birthday;}public void setBirthday(String birthday) {this.birthday = birthday;}public user(String id, String username, String password, String birthday) {this.id = id;this.username = username;this.password = password;this.birthday = birthday;}
}
7.package controller添加控制器usercontroller
@RestController
public class usercontroller {@Autowiredprivate UserMapper usermapper;@GetMapping("/user")public List query(){List <user>list=usermapper.find();System.out.println(list);return list;}@PostMapping("/user")public String save(user user ){int i=usermapper.insert(user);if (i == 0) {return "创建失败";}else return "创建成功";}
}
