springboot集成mybatisPlus(28)

x33g5p2x  于2021-08-23 转载在 Spring  
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一 前言

mybatisPlus 能够简化开发,减少重复代码,很不错的一个项目!!

二 springboot 集成 mybatisPlus

2.1准备工作

建表语句

CREATE TABLE `customer` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键',
  `customer_name` varchar(255) DEFAULT NULL COMMENT '顾客名称',
  `gender` varchar(255) DEFAULT NULL COMMENT '性别',
  `telephone` varchar(255) DEFAULT NULL COMMENT '电话号码',
  `register_time` timestamp NULL DEFAULT NULL COMMENT '注册时间',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=26 DEFAULT CHARSET=utf8 COMMENT='顾客表';

项目依赖

 <dependencies>
        <!-- -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- 测试 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- mybaits plus 插件 -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.0.5</version>
        </dependency>

        <!-- 阿里数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.22</version>
        </dependency>
        <!-- 数据库驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!-- lombok简化代码 -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

    </dependencies>

2.2 配置文件

看 mybatis-plus相关配置; 关键点是 全局 id 的配置;

  • 主键类型 0:"数据库ID自增";
  • 1:"用户输入ID";
  • 2:"全局唯一ID (数字类型唯一ID)";
  • 3:"全局唯一ID UUID";
# 配置端口
server:
  port: 8085
  servlet:
    context-path: /zszxz
    application-display-name: mybatis-plus-demo

spring:
  application:
    name: mybatis-plus-demo
  # 配置数据源
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/zszxz?allowMultiQueries=true&useUnicode=true&characterEncoding=UTF8&zeroDateTimeBehavior=convertToNull&useSSL=false
    username: root
    password: 
    driver-class-name: com.mysql.jdbc.Driver
    druid:
      filters: stat
      maxActive: 20
      initialSize: 1
      maxWait: 60000
      minIdle: 1
      timeBetweenEvictionRunsMillis: 60000
      minEvictableIdleTimeMillis: 300000
      validationQuery: select '1'
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      poolPreparedStatements: true
      maxOpenPreparedStatements: 20

# mybatis-plus相关配置
mybatis-plus:
  # xml扫描,多个目录用逗号或者分号分隔(告诉 Mapper 所对应的 XML 文件位置)
  mapper-locations: classpath:**/*Mapper.xml
  # 以下配置均有默认值,可以不设置
  global-config:
    banner: false
    db-config:
      #主键类型  0:"数据库ID自增", 1:"用户输入ID",2:"全局唯一ID (数字类型唯一ID)", 3:"全局唯一ID UUID";
      id-type: 0
      #字段策略 0:"忽略判断",1:"非 NULL 判断"),2:"非空判断"
      field-strategy: 2
      #驼峰下划线转换
      table-underline: true
    #数据库大写下划线转换
    #capital-mode: true
    #序列接口实现类配置
    #key-generator: com.baomidou.springboot.xxx
    #逻辑删除配置
    #logic-delete-value: 0 # 逻辑已删除值(默认为 1)
    #logic-not-delete-value: 1 # 逻辑未删除值(默认为 0)
    #自定义填充策略接口实现
    #    meta-object-handler: com.zhengqing.config.MyMetaObjectHandler
    #自定义SQL注入器
    #sql-injector: com.baomidou.springboot.xxx
  configuration:
    # 是否开启自动驼峰命名规则映射:从数据库列名到Java属性驼峰命名的类似映射
    map-underscore-to-camel-case: true
    cache-enabled: false
    # 如果查询结果中包含空值的列,则 MyBatis 在映射的时候,不会映射这个字段
    #    call-setters-on-nulls: true
    # 这个配置会将执行的sql打印出来,在开发或测试的时候可以用
    #    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
    # 解决oracle更新数据为null时无法转换报错,mysql不会出现此情况
    jdbc-type-for-null: 'null'

2.3 实体

  • @TableName 映射数据库表名
  • @TableId 对应主键类型,局部配置;
  • @TableField 注解对应数据库字段
/**
 * @Author lsc
 * <p> </p>
 */
@Data
@TableName("customer")// 映射数据库表名
public class Customer {
    //主键
    @TableId(type = IdType.AUTO)
    private Long id;

    // 如果字段和数据库列对应可省略该注解
    // @TableField(value = "NAME",exist = true)
    private String customerName;

    private String gender;

    private String telephone;

    private String registerTime;
}

2.4 mapper

mapper 多了继承 BaseMapper

/**
 * @Author lsc
 * <p> </p>
 */
@Repository
@Mapper
public interface CustomerMapper extends BaseMapper<Customer> {


}

2.5 映射文件

与普通的mybatis映射文件一样;如果要使用原生的Mybatis 方法,自定义即可,跟原来没区别;

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >

<mapper namespace="com.zszxz.plus.mapper.CustomerMapper">

</mapper>

2.6 分页配置

分页

/**
 * @Author lsc
 * <p> </p>
 */
@Configuration
@MapperScan("com.zszxz.plus.service.*.mapper*")
public class MybatisPlusConfig {

    @Bean
    public PaginationInterceptor paginationInterceptor() {
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        // 设置请求的页面大于最大页后操作, true调回到首页,false 继续请求  默认false
        // paginationInterceptor.setOverflow(false);
        // 设置最大单页限制数量,默认 500 条,-1 不受限制
        // paginationInterceptor.setLimit(500);
        return paginationInterceptor;
    }
}

2.7 启动类

@SpringBootApplication
// 扫描mapper文件
@MapperScan("com.zszxz.plus.mapper")
public class SpringbootMybatisPlusApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootMybatisPlusApplication.class, args);
    }

}

2.8测试

集成 mybatis plus 后 会有一些默认 的crud方法, 简化开发;

@SpringBootTest
@RunWith(SpringRunner.class)
public class SpringbootMybatisPlusApplicationTests {



    @Autowired
    CustomerMapper customerMapper;

    @Test
    public  void add() {
        Customer customer = new Customer();
        customer.setCustomerName("大牛");
        customer.setGender("男");
        customer.setTelephone("66566");
        customerMapper.insert(customer);
    }

    @Test
    public  void update() {
        Customer customer = new Customer();
        customer.setId(26L);
        customer.setCustomerName("大牛哥");
        customer.setGender("男");
        customer.setTelephone("66566");
        customerMapper.updateById(customer);
    }

    @Test
    public  void delete() {

        customerMapper.deleteById(24L);
    }

    @Test
    public  void selectByid() {

        Customer customer = customerMapper.selectById(26L);
        // Customer(id=26, customerName=大牛哥, gender=男, telephone=66566, registerTime=null)
        System.out.println(customer);
    }

    @Test
    public  void selectByWrapper() {

		// 条件封装
        QueryWrapper<Customer> wrapper = new QueryWrapper<>();
        wrapper.eq("id",26L);
        List<Customer> customers = customerMapper.selectList(wrapper);
        // [Customer(id=26, customerName=大牛哥, gender=男, telephone=66566, registerTime=null)]
        System.out.println(customers);
    }



    @Test
    public  void page() {
        Page<Customer> page = new Page<>(1, 2);
        IPage<Customer> customerIPage = customerMapper.selectPage(page, null);
        System.out.println(customerIPage);
    }


}

2.9 json类型处理

实体类 需要 实现序列化接口,查询的时候需要 在注解上加 autoResultMap = true; 不同的类型处理器引入相应的依赖;Mybatis plus 3.2版本以上;

@Data
@TableName(value = "identify_color_card",autoResultMap = true)
public class ColorCard implements Serializable {


	// .........
    @TableField(typeHandler = FastjsonTypeHandler.class)
    private Object colorCard;

}

2.10 自动插入处理

@Data
@TableName(value = "identify_color_card")
public class ColorCard  {


    @JsonFormat(timezone = "GMT+8",pattern = "yyyy-MM-dd HH:mm:ss")
    @DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
    @TableField(fill = FieldFill.INSERT)
    private LocalDateTime createAt;

    @JsonFormat(timezone = "GMT+8",pattern = "yyyy-MM-dd HH:mm:ss")
    @DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updateAt;

}

需要实现 MetaObjectHandler 类

/**
 * @Author lsc
 * <p> </p>
 */
@Component
public class MetaObjectHandlerConfig implements MetaObjectHandler {

    /**
     * 添加操作的时候会将createTime和updateTime加入到数据库中
     *
     * @param metaObject
     */
    @Override
    public void insertFill(MetaObject metaObject) {

        this.setFieldValByName("createAt", LocalDateTime.now(), metaObject);
        this.setFieldValByName("updateAt", LocalDateTime.now(), metaObject);
    }

    /**
     * 执行修改操作的时候运行
     *
     * @param metaObject
     */
    @Override
    public void updateFill(MetaObject metaObject) {

        this.setFieldValByName("updateAt", LocalDateTime.now(), metaObject);
    }
}

更多内容参照官网

官网: https://baomidou.com/

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