SpringBoot ---- MyBatis Plus 入门

配置文件

• pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <!-- MySQL 驱动 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <!-- lomok 简化 Java 代码 -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <!-- MyBatis Plus -->
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>3.3.1</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>

• application.yml

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8&useSSL=false
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver

• 测试用表结构及数据

/*
 Navicat Premium Data Transfer

 Source Server         : mysql57
 Source Server Type    : MySQL
 Source Server Version : 50728
 Source Host           : localhost:3306
 Source Schema         : test

 Target Server Type    : MySQL
 Target Server Version : 50728
 File Encoding         : 65001

 Date: 24/02/2020 14:51:03
*/

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for t_user
-- ----------------------------
DROP TABLE IF EXISTS `t_user`;
CREATE TABLE `t_user`  (
  `id` bigint(20) NOT NULL,
  `name` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `age` int(2) NOT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of t_user
-- ----------------------------
INSERT INTO `t_user` VALUES (1, 'Jeson', 2);
INSERT INTO `t_user` VALUES (2, 'Jack', 3);

编写代码

• 编写实体类 User

/**
 * Data 注解提供类的get、set、equals、hashCode、canEqual、toString方法
 * AllArgsConstructor 提供全参构造
 * NoArgsConstructor 提供无参构造
 * TableName("t_user") 指定实体类对应表名为 "t_user"
 * @author Jeson
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
@TableName("t_user")
public class User {
    /**
     * TableId 注解指定该属性对应表中的主键 id, type 指定主键生成策略
     * TableField 指定该属性对应表中字段名字（在名字不一致或下划线转驼峰命名无法对应时使用）
     */
    @TableId(value = "id", type = IdType.ASSIGN_ID)
    private Long userId;
    @TableField("name")
    private String username;
    private Integer age;
}

• 编写 DAO 层 UserMapper

public interface UserMapper extends BaseMapper<User> {
}

• 编写测试类

@SpringBootTest
class CurdTests {

    @Autowired
    private UserMapper userMapper;

    @Test
    void selectAll() {
        System.out.println("----- selectAll method test ------");
        List<User> userList = userMapper.selectList(null);
        userList.forEach(System.out::println);
    }

    @Test
    void insert() {
        System.out.println("----- insert method test -----");
        int rows = userMapper.insert(new User(null, "testNmae", 11));
        System.out.println(rows);
    }

    @Test
    void update() {
        System.out.println("----- update method test -----");
        int rows = userMapper.updateById(new User(1231590206946033665L, "testName2", 10));
        System.out.println(rows);
    }

    @Test
    void delete() {
        System.out.println("----- delete method test -----");
        int rows = userMapper.deleteById(1231590206946033665L);
        System.out.println(rows);
    }
}

• 简单使用 MyBatis Plus 对数据库进行了 CURD 操作，MyBatis Plus 还有大量使用功能，详情参考官方文档