简述

身为一个后端程序员，当然不可能把所有的东西都背诵下来，正所谓好记性不如烂笔头，我都会把自己经常使用的一些方法记录起来，方便在开发过程中使用。

数据库（MySQL）

查询所有字段

SELECTCOLUMN_NAME,column_comment 
FROMINFORMATION_SCHEMA.COLUMNS 
WHEREtable_name = '你的表名'

查询所有字段并逗号隔开（id,name.code）

SELECTgroup_concat( COLUMN_NAME SEPARATOR ',' ) AS t_info 
FROMinformation_schema.COLUMNS 
WHEREtable_name = '表名称' AND table_schema = '数据库名称';

增加或者减少指定的天数

UPDATE `equipment_monitor_locations`  set create_time = DATE_ADD(`create_time`,INTERVAL 1 DAY)UPDATE `equipment_monitor_locations`  set create_time = DATE_SUB(`create_time`,INTERVAL 1 DAY)

查询指定年份的数据

SELECT id, sensor_code FROM user WHERE YEAR(upload_time) = #{year}

数据库表新增信息

增加默认删除状态ALTER TABLE `sys_menu`ADD `deleted` tinyint(1) DEFAULT '0' COMMENT '删除状态(0:正常 1:删除)';台账表格基础操作时间信息ALTER TABLE `name`ADD create_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',ADD update_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '更新时间';台账表格基础操作人员信息ALTER TABLE `name`ADD create_person VARCHAR(255) NOT NULL COMMENT '创建人员',ADD create_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',ADD update_person VARCHAR(255) NOT NULL COMMENT '更新人员',ADD update_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '更新时间',ADD changes_person VARCHAR(255) NOT NULL COMMENT '变更人员',ADD changes_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '变更时间',ADD delete_person VARCHAR(255) NOT NULL COMMENT '删除人员',ADD delete_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '删除时间';改变人员ALTER TABLE `name`ADD change_person VARCHAR(255) NOT NULL COMMENT '更变人员',ADD change_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '更变时间';ALTER TABLE `name`ADD created_person VARCHAR(255) NOT NULL COMMENT '创建人员',ADD created_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间'ADD updated_person VARCHAR(255) NOT NULL COMMENT '更新人员',ADD updated_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '更新时间'ADD deleted_person VARCHAR(255) NOT NULL COMMENT '删除人员',ADD deleted_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '删除时间';

case

( CASE WHEN ( pmc.manoeuvre_change_state = 1 ) THEN pmc.id ELSE NULL END ) AS num

用 EXISTS 或 NOT EXISTS 代替 IN 或 NOT IN

select *  from test1 where EXISTS (select * from test2  where id2 = id1 )select *  FROM test1  where NOT EXISTS (select * from test2  where id2 = id1 )

7位设备编码补零生成

        SELECT( CASE WHEN sum.count < 10000000 THEN LPAD( sum.count, 7, '0' ) ELSE sum.count END ) AS sum_code_numFROM( SELECT COUNT(id) AS `count` FROM `device_info`) AS sum

查询相同id下，最新的一条数据

SELECT a.*
FROM alarm_dispose a
INNER JOIN (SELECT alarm_id, MAX(alarm_time) as max_alarm_time, MAX(id) AS idFROM alarm_disposeGROUP BY alarm_id
) b ON a.alarm_id = b.alarm_id AND a.alarm_time = b.max_alarm_time AND a.id = b.id;

SELECT a.*
FROM alarm_dispose a
INNER JOIN (SELECT alarm_id, MAX(alarm_time) as max_alarm_timeFROM alarm_disposeGROUP BY alarm_id
) b ON a.alarm_id = b.alarm_id AND a.alarm_time = b.max_alarm_time
WHERE a.id = (SELECT MAX(id)FROM alarm_dispose cWHERE c.alarm_id = a.alarm_id AND c.alarm_time = a.alarm_time
);

Spring Boot

常用注解

数据库事务注解

@Transactional(rollbackFor = Exception.class)

常用实体补充

    import com.fasterxml.jackson.annotation.JsonFormat;import org.springframework.format.annotation.DateTimeFormat;@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone = "GMT+8")@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")@ApiModelProperty("创建时间")private Date createTime;@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone = "GMT+8")@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")@ApiModelProperty("更新时间")private Date updateTime;

long自动转字符串

import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
@JsonSerialize(using = ToStringSerializer.class)

枚举类

import lombok.AllArgsConstructor;
import lombok.Getter;/*** 预警类别** @author dpe*/
@AllArgsConstructor
@Getter
public enum AlarmGradeEnum {/*** 一级预警*/ONE(1,"一级预警"),/*** 二级预警*/TWO(2,"二级预警"),/*** 三级预警*/THREE(3,"三级预警");private final Integer code;private final String name;public static Integer getCode(String name) {for (AlarmGradeEnum record : AlarmGradeEnum.values()) {if (record.name.equals(name)) {return record.code;}}return null;}public static String getName(Integer code) {for (AlarmGradeEnum record : AlarmGradeEnum.values()) {if (record.code.equals(code)) {return record.name;}}return null;}public static AlarmGradeEnum get(Integer code) {for (AlarmGradeEnum record : AlarmGradeEnum.values()) {if (record.code.equals(code)) {return record;}}return null;}
}

常用函数

    /*** 生成随机整数** @param min 最小区间* @param max 最大区间* @return 随机整数*/public int generatingRandomInt(int min, int max) {double randomValue = min + (max - min + 1) * Math.random();return (int) randomValue;}

流处理-list转map

    public Map<String, User> convertListToMap(List<User> userList) {if (deviceInfoList == null) {return new HashMap<>(); // 返回空Map，或者抛出异常，取决于你的需求}Map<String, User> userMap = userList.stream().filter(user -> user.getCode() != null) // 判空过滤.collect(Collectors.toMap(User::getTermigetCodenalNo, user -> user));return userMap;}

list转map

        List<SysMenu> sysMenuList = menuMapper.selectList(null);HashMap<Long, List<SysMenu>> map = new HashMap<>();for (SysMenu item:sysMenuList){Long parentId = item.getParentId();List<SysMenu> sysMenuMapList = new ArrayList<>();if(map.containsKey(parentId)){sysMenuMapList = map.get(parentId);}sysMenuMapList.add(item);map.put(parentId, sysMenuMapList);}

list排序

自然正序

Comparator.naturalOrder()

自然倒叙

Comparator.reverseOrder()

// 根据list中的一个字段，对集合重新排序(不能处理空值)
List<User> newList = list.stream().sorted(Comparator.comparing(User::getAge)).collect(Collectors.toList());// 使用 nullsLast() 方法，将空值排在最后：
newList = newList.stream().sorted(Comparator.comparing(User::getAge, Comparator.nullsLast(Comparator.naturalOrder()))).collect(Collectors.toList());// 使用 nullsFirst() 方法，将空值排在最前：
newList = newList.stream().sorted(Comparator.comparing(User::getAge, Comparator.nullsFirst(Comparator.naturalOrder()))).collect(Collectors.toList());

时间类型

获取当天的开始时间

DateTime beginOfDay = DateUtil.beginOfDay(new Date());

获取当天的结束时间

DateTime endOfDay = DateUtil.endOfDay(new Date());

数据校验函数

验证手机号码与座机号码

    /*** 验证手机号码与座机号码** @param phone 号码* @return 正确/错误*/public static boolean phoneVerification(String phone) {// 验证手机号码String mobilePattern = "^1(3[0-9]|4[5-9]|5[0-35-9]|66|7[0-8]|8[0-9]|9[0-35-9])\\d{8}$";Pattern patternMobile = Pattern.compile(mobilePattern);Matcher matcherMobile = patternMobile.matcher(phone);boolean phoneNum = matcherMobile.matches();// 验证座机号码String telephonePattern = "^(0[1-9]\\d{1,2}-?)?([2-9]\\d{6,7})$";Pattern patternTelephone = Pattern.compile(telephonePattern);Matcher matcherTelephone = patternTelephone.matcher(phone);boolean matcher = matcherTelephone.matches();// 验证座机号码(不带区号)String telephonePatternShort = "^(0[1-9]\\d{1,2}-?)?([2-9]\\d{6,7})|(\\d{7,8})$";Pattern patternTelephoneShort = Pattern.compile(telephonePatternShort);Matcher matcherTelephoneShort = patternTelephoneShort.matcher(phone);boolean matcherShort = matcherTelephoneShort.matches();return phoneNum || matcher || matcherShort;}

实体通用字段

@ApiModelProperty(value = "删除状态(0:正常 1:删除)")private Integer deleted;

Optional判空

Optional<SosInfo> sosInfoOptional = sosInfoRepository.findById(id);
SosInfo sosInfo = sosInfoOptional.orElse(null);

Optional<DeviceInfo> deviceInfoOptional = deviceInfoRepository.findById(id);
if (deviceInfoOptional.isPresent()) {DeviceInfo deviceInfo = deviceInfoOptional.get();
}

测试类

普通测试类

import org.junit.Test;/*** @author fir*/
public class DataServiceTest {@Testpublic void a(){System.out.println("asdasda");}
}

实体注解

自定义字段，不作为数据库表字段使用

@TableField(exist = false)

雪花算法主键

    @JsonSerialize(using= ToStringSerializer.class)@TableId(value = "role_id", type = IdType.ASSIGN_ID)

时间格式转换实体字段

import com.fasterxml.jackson.annotation.JsonFormat;import org.springframework.format.annotation.DateTimeFormat;    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone = "GMT+8")@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")

xml文件特殊符号替换符

  &lt; < 小于号 &gt; > 大于号 &amp; & 和 &apos; ' 单引号 &quot; " 双引号

数据提交验证

@ApiOperation("添加数据")@PostMapping("/insertData")public AjaxResult insertData(@Validated Demo demo){return AjaxResult.success(iDemoService.insertData(demo));}

实体中

// 字符串类型，表示不能超过5个字符（abcde）Length(max = 5,message = "名称 不能超过 5 个字符")@ApiModelProperty(value = "名称")@ExcelProperty(index = 1)private String name;数值类型，表示不能大于1（<=1）@Range(max = 1, message = "状态 不能超过 1 个字符")@ApiModelProperty(value = "状态(0:未上报,1:已上报,2:变更中)")private Integer state;

对于
reason longtext COMMENT ‘内容’
字段长度应为

@Length(max = 65535, message = "内容 不能超过 65535 个字符")@ApiModelProperty(value = "内容")private String reason;

递归处理树形结构

树形实体

package com.lnsoft.mmbdf.yjglpt.project.dto.mt;import com.fasterxml.jackson.databind.annotation.JsonSerialize;import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;import io.swagger.annotations.ApiModelProperty;import lombok.AllArgsConstructor;import lombok.Builder;import lombok.Data;import lombok.NoArgsConstructor;import java.util.List;/*** 级联选择器对象* @author fir*/@Data@Builder@AllArgsConstructor@NoArgsConstructorpublic class TreeIntegerDTO {@JsonSerialize(using= ToStringSerializer.class)@ApiModelProperty(value = "数值")private Long value;@ApiModelProperty(value = "标签")private String label;@ApiModelProperty(value = "可用数值")private Object num;@ApiModelProperty(value = "状态")private Object state;@ApiModelProperty(value = "是否禁用: 是-true 否-false")private Boolean disabled;@ApiModelProperty(value = "子列表")private List<TreeIntegerDTO> children;}

MyBatis-Plus

查询条件

或

lqwList.and((qw) -> qw.eq(ManoeuvreVideo::getType, 0).or().eq(ManoeuvreVideo::getType, 1));

区间

 lqw.between(ManoeuvreVideo::getTime, start, end);

大于小于

// 大于lqw.gt(ManoeuvreVideo::getTime, time);// 大于等于lqw.ge(ManoeuvreVideo::getTime, time);// 小于lqw.lt(ManoeuvreVideo::getTime, time);// 小于等于lqw.le(ManoeuvreVideo::getTime, time);

xml自定义查询

in(foreach)

codeIN <foreach collection="list" index="index" item="item" open="(" separator="," close=")">#{item}</foreach>/*** 装备演练-地市演练次数查看** @return 地市演练次数*/List<PjManoeuvreStatisticsOrgManoeuvre> getStatistics(List<String> list);

if

<if test="type != null and type != ''">t.type = #{type}
</if><if test="state != null and state.size > 0">AND t.state IN<foreach item="state" index="index" collection="state" open="(" separator="," close=")">#{state}</foreach>
</if><if test="array != null and array.length >0">
<if test="list != null and list.size() > 0">

where

<where><if test="type != null and type != ''">t.type = #{type}</if>
</where>

like concat('%', #{menuName}, '%')

自定义查询的分页查询

// 逻辑层中PageInfo<User> resultInfo;Page<User> page = new Page<>(pageNum, pageSize);Page<User> userPage = userMapper.getList(page);resultInfo = new PageInfo<>(userPage.getTotal(), pageNum, userPage.getRecords());// deo层中Page<User> getList(Page<User> page);// xml中<select id="getList" resultType="com.fir.test.dto.mt.User">SELECT name,codeFROM `user`</select>

Swagger

常用注释

@ApiImplicitParams({@ApiImplicitParam(name = "weightJson", value = "指标权重(Json)格式", dataTypeClass = String.class),@ApiImplicitParam(name = "pageNum", value = "页码", defaultValue = "1", dataTypeClass = Integer.class, required = true),@ApiImplicitParam(name = "pageSize", value = "页数量", defaultValue = "10", dataTypeClass = Integer.class, required = true)})

Hutool 工具

手机号码校验
boolean isMobile = Validator.isMobile("18866661234");
1
身份证号校验
boolean isIdCardNumber = Validator.isCitizenId("43312220160113802X");
1
邮箱校验
boolean isEmail = Validator.isEmail("random@example.com");
1
统一社会信用代码校验
boolean isCreditCode = Validator.isCreditCode("91440300701234567A");
1
车牌号码校验
boolean isPlateNumber = Validator.isPlateNumber("粤B12345");
1
车架号校验
boolean isCarVin = Validator.isCarVin("LFV2A21J9D4112345");

历史问题

Mybatis-plus 逻辑删除字段无效

问题描述:

<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId><version>3.0.6</version></dependency>

增加yml配置后仍然无效

mybatis-plus:global-config:db-config:logic-delete-field: deleted # 此版本无该配置项logic-delete-value: 1logic-not-delete-value: 0

实体中一下配置均无效

@TableLogic@ApiModelProperty(value = "删除状态(0:正常 1:删除)")private Integer deleted;

	@TableLogic(value = "0", delval = "1")	@ApiModelProperty(value = "删除状态(0:正常 1:删除)")	private Integer deleted;

解决方法:

实体

@TableLogic
@ApiModelProperty(value = "删除状态(0:正常 1:删除)")
private Integer deleted;

配置类

import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.core.config.GlobalConfig;
import com.baomidou.mybatisplus.core.injector.DefaultSqlInjector;
import com.baomidou.mybatisplus.core.injector.ISqlInjector;
import com.baomidou.mybatisplus.extension.injector.LogicSqlInjector;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.type.JdbcType;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.transaction.annotation.EnableTransactionManagement;import javax.sql.DataSource;
import java.io.IOException;/*** @author dpe* @date 2022/02/10 16:34**/
@Slf4j
@Configuration
public class MybatisPlusConfig {/*** 分页插件* @return bean*/@Beanpublic PaginationInterceptor paginationInterceptor() {return new PaginationInterceptor();}/*** 逻辑删除** @return 注入器*/@Beanpublic ISqlInjector sqlInjector(){return new LogicSqlInjector();}
}

错误案例

更多的人推荐,但这种配置是无效的

/*** 逻辑删除** @return 注入器*/@Beanpublic ISqlInjector sqlInjector(){return new DefaultSqlInjector();}

Invalid bound statement (not found)

问题描述

org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.fir.mybatis.imapper.core.UserMapper.getUser

解决方法

mybatis:config-location: classpath:mybatis-config.xmlmapper-locations: classpath:/mapper/*.xmlmybatis-plus:configuration:map-underscore-to-camel-case: trueauto-mapping-behavior: fulllog-impl: org.apache.ibatis.logging.stdout.StdOutImpl#  mapper-locations: classpath*:mapper/*.xml 去掉该条配置

错误原因

在低版本中配置逻辑删除，有修改配置的方法，但在尝试无效之后，没有及时的清理无用的配置，导致问题出现
临时记录

"fileName": "20231220测试视频.mp4","staticResourcesId": 158253