MyBatis Plus 2.3 个人笔记-04-配置文件与插件使用

  • 接入 springboot application.yml配置

  1.mapper 扫描

mybatis-plus:
  # 如果是放在src/main/java目录下 classpath:/com/yourpackage/*/mapper/*Mapper.xml
  # 如果是放在resource目录 classpath:/mapper/*Mapper.xml
  mapper-locations: classpath:/com/huarui/mybatisplus/mapper/*Mapper.xml
  #实体扫描,多个package用逗号或者分号分隔
  typeAliasesPackage: com.huarui.mybatisplus.entity

  

@SpringBootApplication
@MapperScan("com.huarui.mybatisplus.mapper")
public class Application {

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

}

  

  2.自定义公共字段填充处理器

当我们新增或修改时需要给某个字段 赋值默认值

  

@TableName("tbl_user")
public class User extends Model<User> {

    private static final long serialVersionUID = 1L;

    @TableId(value = "id", type = IdType.ID_WORKER)
    private Long id;


    /**
   * * 新增 修改时 字段自动填充 */ @TableField(fill = FieldFill.INSERT_UPDATE) private String name; }

  

package com.huarui.mybatisplus.configuration;

import com.baomidou.mybatisplus.mapper.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;

/**
 * Created by lihui on 2019/2/17.
 * 自定义公共字段填充处理器
 */
public class MyMetaObjectHandler extends MetaObjectHandler {

    /**
     * 插入操作 自动填充
     */
    @Override
    public void insertFill(MetaObject metaObject) {
        //获取到需要被填充的字段的值
        Object fieldValue = getFieldValByName("name", metaObject);
        if(fieldValue == null) {
            System.out.println("*******插入操作 满足填充条件*********");
            setFieldValByName("name", "youxiu326", metaObject);
        }
    }

    /**
     * 修改操作 自动填充
     */
    @Override
    public void updateFill(MetaObject metaObject) {
        Object fieldValue = getFieldValByName("name", metaObject);
        if(fieldValue == null) {
            System.out.println("*******修改操作 满足填充条件*********");
            setFieldValByName("name", "youxiu326", metaObject);
        }
    }
}
MyMetaObjectHandler.java
mybatis-plus:
  # 如果是放在src/main/java目录下 classpath:/com/yourpackage/*/mapper/*Mapper.xml
  # 如果是放在resource目录 classpath:/mapper/*Mapper.xml
  mapper-locations: classpath:/com/huarui/mybatisplus/mapper/*Mapper.xml
  #实体扫描,多个package用逗号或者分号分隔
  typeAliasesPackage: com.huarui.mybatisplus.entity
  global-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: 2
    #自定义填充策略接口实现
    meta-object-handler: com.huarui.mybatisplus.configuration.MyMetaObjectHandler

  

  3.逻辑删除

@TableName("tbl_user")
public class User extends Model<User> {

    private static final long serialVersionUID = 1L;

    @TableId(value = "id", type = IdType.ID_WORKER)
    private Long id;



    @TableField("deleteFlag")
    @TableLogic //逻辑删除标志
    private Integer deleteFlag;

}

  

mybatis-plus:
  # 如果是放在src/main/java目录下 classpath:/com/yourpackage/*/mapper/*Mapper.xml
  # 如果是放在resource目录 classpath:/mapper/*Mapper.xml
  mapper-locations: classpath:/com/huarui/mybatisplus/mapper/*Mapper.xml
  #实体扫描,多个package用逗号或者分号分隔
  typeAliasesPackage: com.huarui.mybatisplus.entity
  global-config:
    #逻辑删除配置(下面3个配置)
    logic-delete-value: -1    #删除状态
    logic-not-delete-value: 1 #未删除状态
    sql-injector: com.baomidou.mybatisplus.mapper.LogicSqlInjector

  

 4.分页插件 与 乐观锁插件使用

  

@EnableTransactionManagement
@Configuration
@MapperScan("com.huarui.mybatisplus.mapper.*")
public class MybatisPlusConfig {

    /**
     * 分页插件
     */
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        return new PaginationInterceptor();
    }

    /**
     * 乐观锁插件
     */
    @Bean
    public OptimisticLockerInterceptor optimisticLockerInterceptor() {
        return new OptimisticLockerInterceptor();
    }

}

  

    分页插件配置即可使用

  乐观锁实现方式:

  • 取出记录时,获取当前version
  • 更新时,带上这个version
  • 执行更新时, set version = yourVersion+1 where version = yourVersion
  • 如果version不对,就更新失败
@TableName("tbl_employee")
public class Employee extends Model<Employee> {

    private static final long serialVersionUID = 1L;

    /*
	 * @TableId:
	 * 	 value: 指定表中的主键列的列名, 如果实体属性名与列名一致,可以省略不指定.
	 *   type: 指定主键策略.  ID_WORKER 全局唯一ID,内容为空自动填充(默认配置)
	 */
    @TableId(value = "id", type = IdType.ID_WORKER)
    private Long id;


    /**
     * 声明该属性不是数据库中字段
     */
    @TableField(exist = false)
    private String notExist;

    /**
     * 乐观锁版本号
     *  仅支持int,Integer,long,Long,Date,Timestamp
     */
    @Version
    private Integer version;

}

  

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转载自www.cnblogs.com/youxiu326/p/mybatiPlus-04.html