当前位置: 首页 > news >正文

RabbitMQ应用问题——消息补偿机制以及代码示例

RabbitMQ应用问题——消息补偿机制以及代码示例

RabbitMQ应用问题

  • 消息可靠性的保障
    • 消息补偿机制

在这里插入图片描述

详细说明

这里使用了简单的代码进行演示,订单的消费者没有写,在订单的消费同时,发送一条增加积分消息到积分队列。

详细流程途中都有注明。

为了更加清楚代码这里进行表明功能。

在这里插入图片描述

gitee地址

1.创建mq-manager父工程

1.1导入依赖

 <packaging>pom</packaging><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.7.0</version><relativePath/> <!-- lookup parent from repository -->
</parent><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-amqp</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>2.0.7</version></dependency></dependencies>

2.创建mq-common子模块

2.1导入依赖

<dependencies><!-- mybatis-plus --><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.2</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId><version>1.2.6</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></dependency>
</dependencies>

2.2编写实体类

2.2.1Order
package com.qf.entity;import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;import java.math.BigDecimal;
import java.util.Date;
/*{ "bizNo": "20200803173145877","status": 1,"price": 34.12,"goodId": 1002,"userId": 100}*///订单
@TableName("orders")
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Order {@TableId(value = "id", type = IdType.AUTO)private Integer id;@TableField(value = "biz_no")private String bizNo; //业务编号@TableField(value = "status")private Integer status;@TableField(value = "price")private BigDecimal price;@TableField(value = "create_time")private Date createTime;@TableField(value = "pay_time")private Date payTime;@TableField(value = "good_id")private Integer goodId;@TableField(value = "user_id")private Integer userId;//exist = false:该属性不使用@TableField(value = "num", exist = false)private Integer num;
}
2.2.2Integral
package com.qf.entity;import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;import java.util.Date;//积分
@TableName("integral")
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Integral{@TableId(type = IdType.AUTO)private Integer id;@TableField("user_id")private Integer userId;private Long score;private String msg;@TableField("create_time")private Date createTime;
}
2.2.3Msg
package com.qf.entity;import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;import java.util.Date;//消息
@TableName("message")
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Msg {@TableId(value = "id")private String id;@TableField(value = "exchange")private String exchange;@TableField(value = "routing_key")private String routingKey;@TableField(value = "content")private String content; // 消息的内容@TableFieldprivate Integer status; // 消息的状态@TableField(value = "try_count")private int tryCount; //尝试次数@TableField(value = "create_time")private Date createTime;
}

2.3编写公共参数

2.3.1IntegralConstant
package com.qf.contant;//设置系统中的参数
public class IntegralConstant {// 积分系统队列public final static String INTEGRAL_QUEUE = "integral_queue";// 积分系统交换机public final static String INTEGRAL_EXCHANGE = "integral_exchange";// 积分系统的 routing-keypublic final static String INTEGRAL_ROUTING_KEY= "integral_routing_key";
}
2.3.2DeadConstant
package com.qf.contant;//死信
public class DeadConstant {//死信交换机public static final String DEAD_LETTER_EXCHANGE = "dead_letter_exchange";//死信路由键public static final String DEAD_LETTER_ROUTING_KEY = "dead_letter_routing_key";//死信队列public static final String DEAD_LETTER_QUEUE = "dead_letter_queue";
}

3.编写mq-order子模块

3.1导入公共模块

<dependencies><dependency><groupId>com.qf</groupId><artifactId>mq-common</artifactId><version>1.0-SNAPSHOT</version></dependency>
</dependencies>

3.2编写配置文件

server:port: 8080spring:datasource:username: rootpassword: rooturl: jdbc:mysql://localhost:3306/mq?serverTimezone=Asia/Shanghai&characterEncoding=utf8driver-class-name: com.mysql.cj.jdbc.Drivertype: com.alibaba.druid.pool.DruidDataSourcerabbitmq:username: guestpassword: guesthost: 192.168.25.129port: 5672publisher-confirm-type: simplepublisher-returns: truemybatis-plus:mapper-locations: classpath:mapper/*.xmlconfiguration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl#驼峰形式map-underscore-to-camel-case: true

3.3编写启动类

package com.qf;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
@MapperScan("com.qf.mapper")
public class OrderApplication {public static void main(String[] args) {SpringApplication.run(OrderApplication.class,args);}
}

3.4编写OrderController

package com.qf.controller;import com.qf.entity.Order;
import com.qf.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
@RequestMapping("order")
public class OrderController {@Autowiredprivate OrderService orderService;@PostMapping("insertOrder")public String insertOrder(@RequestBody Order order){orderService.insertOrder(order);return "success";}}

3.5编写OrderService

package com.qf.service;import com.qf.entity.Order;public interface OrderService {/*** 插入订单* @param order*/void insertOrder(Order order);
}

3.6编写OrderServiceImpl

package com.qf.service.impl;import com.alibaba.fastjson.JSON;
import com.qf.contant.IntegralConstant;
import com.qf.entity.Integral;
import com.qf.entity.Msg;
import com.qf.entity.Order;
import com.qf.mapper.MsgMapper;
import com.qf.mapper.OrderMapper;
import com.qf.service.OrderService;
import org.springframework.amqp.core.*;
import org.springframework.amqp.rabbit.connection.CorrelationData;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;import javax.annotation.Resource;
import java.util.Date;
import java.util.UUID;@Service
@Transactional
public class OrderServiceImpl implements OrderService {@Autowiredprivate OrderMapper orderMapper;@Autowiredprivate MsgMapper msgMapper;@Resourceprivate RabbitTemplate rabbitTemplate;@Overridepublic void insertOrder(Order order) {//插入订单orderMapper.insert(order);//插入积分,是把积分信息发送到消息队列中Integral integral = new Integral();integral.setUserId(order.getUserId());//积分对应的用户id就是下订单的用户idintegral.setScore(10L);integral.setMsg("购物积分");integral.setCreateTime(new Date());//把积分对象,转换为Json类型,发送到消息队列中String integralJson = JSON.toJSONString(integral);//创建消息对象,如果消息消费成功了,再去删除对应的消息Msg msg = new Msg();//分布式环境下,id必须是唯一的,解决方案:百度的uid-generator,美团开源项目LeafString uuid = UUID.randomUUID().toString();msg.setId(uuid);msg.setExchange(IntegralConstant.INTEGRAL_EXCHANGE);//积分对应的交换机msg.setRoutingKey(IntegralConstant.INTEGRAL_ROUTING_KEY);//积分对象的路由的keymsg.setContent(integralJson);//积分的Json对象msg.setStatus(-1);//状态msg.setTryCount(0);//尝试次数msg.setCreateTime(new Date());//时间//插入消息msgMapper.insert(msg);//发送消息,需要把Msg对象的id(就是uuid)传过来,一旦消息消费成功,还要去Msg对应表中把该消息删除CorrelationData correlationData = new CorrelationData(uuid);System.out.println("uuid:" + uuid);System.out.println("correlationData.getId():" + correlationData.getId());//发送rabbitTemplate.convertAndSend(IntegralConstant.INTEGRAL_EXCHANGE,IntegralConstant.INTEGRAL_ROUTING_KEY,buildMessage(integralJson,uuid),correlationData);}//构建消息private Message buildMessage(String body,String messageId){//获取MessagePropertiesBuilder对象MessagePropertiesBuilder messagePropertiesBuilder = MessagePropertiesBuilder.newInstance();//获取MessageProperties对象MessageProperties messageProperties = messagePropertiesBuilder.build();messageProperties.setMessageId(messageId);messageProperties.setDeliveryMode(MessageDeliveryMode.PERSISTENT);//消息持久化Message message = new Message(body.getBytes(),messageProperties);System.out.println("message传递的内容:" + new String(message.getBody()));System.out.println("message传递的uuid:" + message.getMessageProperties().getMessageId());return message;}
}

3.7编写OrderMapper

package com.qf.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.qf.entity.Order;
import org.springframework.stereotype.Repository;@Repository
public interface OrderMapper extends BaseMapper<Order> {
}

3.8编写MsgMapper

package com.qf.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.qf.entity.Msg;
import org.springframework.stereotype.Repository;@Repository
public interface MsgMapper extends BaseMapper<Msg> {
}

3.9编写配置类

3.9.1DeadConfig
package com.qf.config;import com.qf.constant.DeadConstant;
import org.springframework.amqp.core.Binding;
import org.springframework.amqp.core.BindingBuilder;
import org.springframework.amqp.core.DirectExchange;
import org.springframework.amqp.core.Queue;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
public class DeadConfig {//创建队列@Beanpublic Queue createDeadQueue(){return new Queue(DeadConstant.DEAD_LETTER_QUEUE);}//创建交换机@Beanpublic DirectExchange createDeadExchange(){//交换机默认持久化return new DirectExchange(DeadConstant.DEAD_LETTER_EXCHANGE);}//绑定:交换机中的消息可以发送到不同的队列@Beanpublic Binding bindingDeadQueue(){//需要设置routingKeyreturn BindingBuilder.bind(createDeadQueue()).to(createDeadExchange()).with(DeadConstant.DEAD_LETTER_ROUTING_KEY);//和发送消息时的routingKey一致}
}
3.9.2IntegralConfig
package com.qf.config;import com.qf.constant.DeadConstant;
import com.qf.constant.IntegralConstant;
import org.springframework.amqp.core.Binding;
import org.springframework.amqp.core.BindingBuilder;
import org.springframework.amqp.core.DirectExchange;
import org.springframework.amqp.core.Queue;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;import java.util.HashMap;
import java.util.Map;//路由模式
@Configuration
public class IntegralConfig {//创建队列@Beanpublic Queue createIntegralQueue(){Map<String, Object> arguments = new HashMap<>();arguments.put("x-dead-letter-exchange", DeadConstant.DEAD_LETTER_EXCHANGE);arguments.put("x-dead-letter-routing-key", DeadConstant.DEAD_LETTER_ROUTING_KEY);return new Queue(IntegralConstant.INTEGRAL_QUEUE,true,false,false,arguments);}//创建交换机@Beanpublic DirectExchange createIntegralExchange(){//交换机默认持久化return new DirectExchange(IntegralConstant.INTEGRAL_EXCHANGE);}//绑定:交换机中的消息可以发送到不同的队列@Beanpublic Binding bindingIntegralQueue(){//需要设置routingKeyreturn BindingBuilder.bind(createIntegralQueue()).to(createIntegralExchange()).with(IntegralConstant.INTEGRAL_ROUTING_KEY);//和发送消息时的routingKey一致}}
3.9.3PublisherConfirmAndReturnConfig
package com.qf.config;import com.qf.entity.Msg;
import com.qf.mapper.MsgMapper;
import lombok.extern.slf4j.Slf4j;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.ReturnedMessage;
import org.springframework.amqp.rabbit.connection.CorrelationData;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.util.Date;
import java.util.HashMap;@Slf4j
@Configuration
public class PublisherConfirmAndReturnConfig implementsRabbitTemplate.ConfirmCallback,RabbitTemplate.ReturnsCallback {@Resourceprivate RabbitTemplate rabbitTemplate;@Autowiredprivate MsgMapper msgMapper;@PostConstructpublic void init(){rabbitTemplate.setConfirmCallback(this);rabbitTemplate.setReturnsCallback(this);}@Overridepublic void confirm(CorrelationData correlationData, boolean ack, String s) {//判断if(ack){log.info("已到达broker");log.info("correlationData id is {}",correlationData.getId());//删除存到数据库中的消息//msgMapper.deleteById(correlationData.getId());//通过id删除//设置删除条件HashMap<String, Object> map = new HashMap<>();map.put("id",correlationData.getId());map.put("status",-1);//多条件删除msgMapper.deleteByMap(map);}else{log.info("没有到达broker,实际上消息已经保存到mysql中,也可以保存到redis中");}}//return机制,该方法比confirm先执行,只要未到达队列的时候才执行@Overridepublic void returnedMessage(ReturnedMessage returnedMessage) {log.info("消息未到达队列");//如果消息到达队列不执行以下代码//消息已经从数据库被删除了//考虑人工干预,获取消息信息进行保存String exchange = returnedMessage.getExchange();String routingKey = returnedMessage.getRoutingKey();Message message = returnedMessage.getMessage();//创建消息对象,如果消息消费成功了,再去删除对应的消息Msg msg = new Msg();msg.setId(message.getMessageProperties().getMessageId());msg.setExchange(exchange);//积分对应的交换机msg.setRoutingKey(routingKey);//积分对象的路由的keymsg.setContent(new String(message.getBody()));//积分的Json对象msg.setStatus(-2);//状态可以设置为和之前不一样msg.setTryCount(0);//尝试次数msg.setCreateTime(new Date());//时间//插入消息msgMapper.insert(msg);//做进一步处理:给管理员发邮件,发短信....}
}

4.创建mq-integral子模块

4.1导入依赖

<dependencies><dependency><groupId>com.qf</groupId><artifactId>mq-common</artifactId><version>1.0-SNAPSHOT</version></dependency><dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.4</version></dependency>
</dependencies>

4.2编写配置文件

server:port: 8081spring:datasource:username: rootpassword: rooturl: jdbc:mysql://localhost:3306/mq?serverTimezone=Asia/Shanghai&characterEncoding=utf8driver-class-name: com.mysql.cj.jdbc.Drivertype: com.alibaba.druid.pool.DruidDataSourcerabbitmq:username: guestpassword: guesthost: 192.168.25.134port: 5672listener:simple:retry:enabled: true #开启消息重试max-attempts: 3 #最大重试次数initial-interval: 2000ms #每次重试的时间间隔multiplier: 2 #每次重试时间乘以当前倍数#重试机制必须是自动ack,才能放到死信队列中acknowledge-mode: automybatis-plus:mapper-locations: classpath:mapper/*.xmlconfiguration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl#驼峰形式map-underscore-to-camel-case: true

4.3编写启动类

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
@MapperScan("com.qf.mapper")
public class IntegralApplication {public static void main(String[] args) {SpringApplication.run(IntegralApplication.class,args);}
}

4.4编写IntegralImpl

package com.qf.service.impl;import com.alibaba.fastjson.JSON;
import com.qf.constant.IntegralConstant;
import com.qf.entity.Integral;
import com.qf.mapper.IntegralMapper;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;import java.util.Random;
import java.util.concurrent.TimeUnit;@Service
public class IntegralImpl {@Autowiredpublic IntegralMapper integralMapper;@Autowiredprivate StringRedisTemplate stringRedisTemplate;//    //第一种方式    
//    @RabbitListener(
//            bindings = @QueueBinding(
//                    value = @Queue(name = IntegralConstant.INTEGRAL_QUEUE,
//                    durable = "true"
//            ),
//            key = {IntegralConstant.INTEGRAL_ROUTING_KEY},
//            exchange = @Exchange(name = IntegralConstant.INTEGRAL_EXCHANGE, durable = "true")
//    ))
//    public void insertIntegral(Message message){
//        //积分信息
//        String integralJson = new String(message.getBody());
//        System.out.println(integralJson);
//
//        //类型转换
//        Integral integral = JSON.parseObject(integralJson, Integral.class);
//        System.out.println(integral);
//        //插入数据库
//        integralMapper.insert(integral);
//    }//    //第二种方式  
//    @RabbitListener(queues = IntegralConstant.INTEGRAL_QUEUE)
//    public void insertIntegral(Message message) throws InterruptedException {
//        //积分信息
//        String integralJson = new String(message.getBody());
//        System.out.println(integralJson);
//
//        //运行成功
//        //类型转换
//        Integral integral = JSON.parseObject(integralJson, Integral.class);
//        System.out.println(integral);
//        //插入数据库
//        integralMapper.insert(integral);
//
//        //测试消息重复消费
//        //直到方法执行完毕,才会ack
//        Thread.sleep(500000);
//
//        //测试消息重试
//        //System.out.println("当前系统时间:"+System.currentTimeMillis());
//        //运行失败
//        //throw new RuntimeException("消息消费异常...");
//    }@RabbitListener(queues = IntegralConstant.INTEGRAL_QUEUE)public void receiveIntegralMessage(Message message){//获取要被消息的消息idString messageId = message.getMessageProperties().getMessageId();//判断,如果redis中没有这个消息id的key,则是第一次消费该消息if(!stringRedisTemplate.hasKey(messageId)){//获取积分信息String integralJson = new String(message.getBody());//类型转换Integral integral = JSON.parseObject(integralJson, Integral.class);//插入到数据库integralMapper.insert(integral);//使用hutool工具类生成随机数int randomInt = RandomUtil.randomInt(10, 100);//往redis中也存一份stringRedisTemplate.opsForValue().setIfAbsent(messageId,String.valueOf(randomInt),600, TimeUnit.SECONDS);}}

4.5编写IntegralMapper

package com.qf.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.qf.entity.Integral;
import org.springframework.stereotype.Repository;@Repository
public interface IntegralMapper extends BaseMapper<Integral> {
}

5.创建mq-compensate子工程

5.1导入依赖

<dependencies><dependency><groupId>com.qf</groupId><artifactId>mq-order</artifactId><version>1.0-SNAPSHOT</version></dependency>
</dependencies>

4.2编写配置文件

server:port: 8082spring:datasource:username: rootpassword: rooturl: jdbc:mysql://localhost:3306/mq?serverTimezone=Asia/Shanghai&characterEncoding=utf8driver-class-name: com.mysql.cj.jdbc.Drivertype: com.alibaba.druid.pool.DruidDataSourcerabbitmq:username: guestpassword: guesthost: 192.168.25.134port: 5672publisher-confirm-type: simplepublisher-returns: truemybatis-plus:mapper-locations: classpath:mapper/*.xmlconfiguration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl#驼峰形式map-underscore-to-camel-case: true

4.3编写启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;@SpringBootApplication
@EnableScheduling
public class CompensateApplication {public static void main(String[] args) {SpringApplication.run(CompensateApplication.class,args);}
}

4.4编写MassageCompensateTask

package com.qf.task;import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.qf.contant.IntegralConstant;
import com.qf.entity.Msg;
import com.qf.mapper.MsgMapper;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageDeliveryMode;
import org.springframework.amqp.core.MessageProperties;
import org.springframework.amqp.core.MessagePropertiesBuilder;
import org.springframework.amqp.rabbit.connection.CorrelationData;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.Scheduled;import javax.annotation.Resource;
import java.util.List;/**** 消息补偿:隔一段时间,去数据库查询未消费掉的消息,再次执行*/@Configuration
public class MassageCompensateTask {@Autowiredprivate MsgMapper msgMapper;@Resourceprivate RabbitTemplate rabbitTemplate;@Scheduled(cron = "10 * * * * ?")public void compensateTask(){//设置查询条件QueryWrapper<Msg> queryWrapper = new QueryWrapper<>();queryWrapper.eq("status","-2");queryWrapper.lt("try_count","3");//查询消息List<Msg> msgList = msgMapper.selectList(queryWrapper);//判断if(msgList.size() > 0){for(Msg msg : msgList){System.out.println("数据库中的消息id:" + msg.getId());//发送rabbitTemplate.convertAndSend(msg.getExchange(),msg.getRoutingKey(),buildMessage(msg.getContent(),msg.getId()),new CorrelationData(msg.getId()));//设置尝试次数msg.setTryCount(msg.getTryCount() + 1);//修改数据库中的消息msgMapper.updateById(msg);}}}//构建消息private Message buildMessage(String body, String messageId){//获取MessagePropertiesBuilder对象MessagePropertiesBuilder messagePropertiesBuilder = MessagePropertiesBuilder.newInstance();//获取MessageProperties对象MessageProperties messageProperties = messagePropertiesBuilder.build();messageProperties.setMessageId(messageId);messageProperties.setDeliveryMode(MessageDeliveryMode.PERSISTENT);//消息持久化Message message = new Message(body.getBytes(),messageProperties);System.out.println("message传递的内容:" + new String(message.getBody()));System.out.println("message传递的uuid:" + message.getMessageProperties().getMessageId());return message;}
}
http://www.lryc.cn/news/69343.html

相关文章:

  • 量化特征贡献度函数:feature_importances_函数/LGBMClassifier/XGBClassifier
  • 总结JVM重要知识点
  • 奇技淫巧第8期
  • 这个 归并排序详解过程 我能吹一辈子!!!
  • docker版jxTMS使用指南:自动生成代码
  • 聚观早报 | 小冰启动GPT克隆人计划;ofo创始人在美创业改做咖啡
  • 面试造航母,入职拧螺丝,工资离了个大谱...
  • Python+selenium自动化元素定位防踩坑
  • 【计算机组成原理】实验一
  • 前端022_广告模块_修改功能
  • makefile 学习(3):C++的编译及库文件的生成与链接
  • Ceph crush运行图
  • 【分布族谱】泊松分布和二项分布、正态分布的关系
  • 关于QTreeWidget的setData函数
  • Microsoft Office 2003的安装
  • 使用Spring Boot和Spring Cloud实现多租户架构:支持应用多租户部署和管理
  • 智聚北京!相约全球人力资源数智化峰会
  • 工业缺陷检测数据及代码(附代码)
  • CentOS 安装MongoDB 6.0
  • 美团面试,被拷打了一小时....
  • 017+C语言中函数栈帧的创建与销毁(VS2022环境)
  • 马斯克们叫停 GPT-5,更像是场行为艺术
  • 事务基础知识
  • 国产高性能DSP音频处理芯片的工作原理以及应用领域
  • BEVDet4D 论文学习
  • 【设计模式与范式:创建型】43 | 单例模式(下):如何设计实现一个集群环境下的分布式单例模式?
  • Metal入门学习:绘制渲染三角形
  • python 中常见变量类型
  • SVN使用教程(一)
  • 【5.19】四、性能测试—指标、种类