Mybatis-plus常用注解

1. 主键

@TableId(type = IdType.ASSIGN_UUID)

type = IdType.ASSIGN_UUID //uuid
type = IdType.AUTO //数据库id自增
type = IdType.ASSIGN_ID //雪花算法生成id

2. 逻辑删除

@TableLogic

3. 自动填充时间

@TableField(fill = FieldFill.INSERT, select = false)

• 查询不显示，插入数据时自动添加时间

    //查询不显示，插入数据时自动添加时间
	@TableField(fill = FieldFill.INSERT, select = false)
    private LocalDateTime createTime;

	//查询不显示，更新数据时自动添加时间
    @TableField(fill = FieldFill.UPDATE, select = false)
    private LocalDateTime updateTime;

• 对应的添加时间的类

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;

@Component
public class MyMetaObjectHandler implements MetaObjectHandler {

    private final String delFlag = "delFlag";
    private final String createTime = "createTime";
    private final String updateTime = "updateTime";

    @Override
    public void insertFill(MetaObject metaObject) {
        fillCreateMeta(metaObject);
        fillCommonMeta(metaObject);
    }

    @Override
    public void updateFill(MetaObject metaObject) {
        fillUpdateMeta(metaObject);
    }

    private void fillCommonMeta(MetaObject metaObject) {
        if (metaObject.hasGetter(delFlag)) {
            setFieldValByName(delFlag, 0, metaObject);
        }
    }

    private void fillCreateMeta(MetaObject metaObject) {
        if (metaObject.hasGetter(createTime)) {
            setFieldValByName(createTime, LocalDateTime.now(), metaObject);
        }
    }

    private void fillUpdateMeta(MetaObject metaObject) {
        if (metaObject.hasGetter(updateTime)) {
            setFieldValByName(updateTime, LocalDateTime.now(), metaObject);
        }
    }

}

4. 字段类型转换

• 可以使用字符串数组或者JOSNArray
• @TableField(typeHandler = JacksonTypeHandler.class)要配合@TableName(autoResultMap = true)使用，否则查询时没有返回值
• 数据库中对应的字段需要使用varchar类型

@Data
@TableName(autoResultMap = true)
public class User extends Model<User> {
  
	@TableField(typeHandler = JacksonTypeHandler.class)
    private String[] interests;
  
    @TableField(typeHandler = FastjsonTypeHandler.class)
    private JSONArray customInterests;

}

5. 数据库字段脱敏

• 创建脱敏处理类AesEncryptHandler，这里使用aes加密

package com.example.fisher.gradledemo.handler;

import com.baomidou.mybatisplus.core.toolkit.AES;
import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;

import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class AesEncryptHandler extends BaseTypeHandler<String> {

	//密钥
    private static String key = "1234567890abcdef";

    //加密
    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, String parameter, JdbcType jdbcType) throws SQLException {
        ps.setString(i, AES.encrypt(parameter, key));
    }

    //解密
    @Override
    public String getNullableResult(ResultSet rs, String columnName) throws SQLException {
        String columnValue = rs.getString(columnName);
        return AES.decrypt(columnValue, key);
    }

    //解密
    @Override
    public String getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
        String columnValue = rs.getString(columnIndex);
        return AES.decrypt(columnValue, key);
    }

    //解密
    @Override
    public String getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        String columnValue = cs.getString(columnIndex);
        return AES.decrypt(columnValue, key);
    }

}

• 属性上添加注解@TableField，配置处理类AesEncryptHandler，这里同时需要类上添加@TableName(autoResultMap = true)注解，否则查询时，不能反向解析加密字段返回给前端

    @TableField(typeHandler = AesEncryptHandler.class)
    private String interest;

6. 数据库字段不存在

@TableField(exist = false)：表示该属性不为数据库表字段，但又是必须使用的。

@TableField(exist = true)：表示该属性为数据库表字段。

sql打印配置

mybatis-plus.configuration.log-impl = org.apache.ibatis.logging.stdout.StdOutImpl