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我们昨天谈论了对应的redis和mysql进行双写一致的理论篇
我们说了五种更新策略和查看的策略
更新策略可以使用
1.先更新数据库再更新redis (高并发可能导致数据不一致)
2.先更新redis再更新数据库 (高并发可能导致数据不一致)
上述建议加上双检加锁策略来保证mysql的负载没那么高
3.停机更新 (业务允许可以使用)
4.先删除redis再更新数据库 ----延迟双删策略(但是业务时间大概率不好估量)
5.先更新数据库再删除redis 使用canal保证数据一致
--------------------
前面我们说了canal主要是通过二进制binlog的监听来对应进行一个增量的监控
下面我们来玩一玩对应的canal
这里的canal我们可以就当做一个从机,用来做对应的同步操作
下载地址 : Release v1.1.6 · alibaba/canal · GitHub
对mysql进行配置,新加一个canal用户
使用以下sql即可(注:mysql5和8不同)
//mysql5.7 开通用户权限 DROP USER IF EXISTS 'canal'@'%'; CREATE USER 'canal'@'%' IDENTIFIED BY 'canal'; GRANT ALL PRIVILEGES ON *.* TO 'canal'@'%' IDENTIFIED BY 'canal'; FLUSH PRIVILEGES; SELECT * FROM mysql.user;只要结果是这样就代表是ok的
下载之后我们放在linux 下的 /mycanal文件夹下
使用 tar -zxvf 进行对应的解压
之后我们需要修改redis下对应的配置文件
我们只需要修改 /mycanal/conf/example/instance.properties
修改为对应的mysql的ip和端口即可
然后我们需要配置对应的my.ini开启对应的binlog二进制文件
log-bin=mysql-bin #开启 binlog binlog-format=ROW #选择 ROW 模式 server_id=1 #配置MySQL replaction需要定义,不要和canal的 slaveId重复然后我们重启mysql即可,查看binlog是否开启
开启即可
然后我们去对应的bin目录下开启对应的脚本
对应的stop.sh就是停止对应的应用
然后我们可以去对应日志文件查看是否启动成功
分别查看logs下面文件夹的canal.log和example.log即可
然后我们创建对应的数据库和测试数据表
先创建数据库 然后执行以下语句 CREATE TABLE `t_user` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `userName` varchar(100) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=utf8mb4
我们先创建一个项目
然后先配置对应的pom文件
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.atguigu.canal</groupId> <artifactId>canal_demo02</artifactId> <version>1.0-SNAPSHOT</version> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.5.14</version> <relativePath/> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> <junit.version>4.12</junit.version> <log4j.version>1.2.17</log4j.version> <lombok.version>1.16.18</lombok.version> <mysql.version>5.1.47</mysql.version> <druid.version>1.1.16</druid.version> <mapper.version>4.1.5</mapper.version> <mybatis.spring.boot.version>1.3.0</mybatis.spring.boot.version> </properties> <dependencies> <!--canal--> <dependency> <groupId>com.alibaba.otter</groupId> <artifactId>canal.client</artifactId> <version>1.1.0</version> </dependency> <!--SpringBoot通用依赖模块--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <!--swagger2--> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger2</artifactId> <version>2.9.2</version> </dependency> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger-ui</artifactId> <version>2.9.2</version> </dependency> <!--SpringBoot与Redis整合依赖--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-pool2</artifactId> </dependency> <!--SpringBoot与AOP--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-aop</artifactId> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjweaver</artifactId> </dependency> <!--Mysql数据库驱动--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.47</version> </dependency> <!--SpringBoot集成druid连接池--> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.1.10</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>${druid.version}</version> </dependency> <!--mybatis和springboot整合--> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>${mybatis.spring.boot.version}</version> </dependency> <!--通用基础配置junit/devtools/test/log4j/lombok/hutool--> <!--hutool--> <dependency> <groupId>cn.hutool</groupId> <artifactId>hutool-all</artifactId> <version>5.2.3</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>${junit.version}</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>${log4j.version}</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>${lombok.version}</version> <optional>true</optional> </dependency> <!--persistence--> <dependency> <groupId>javax.persistence</groupId> <artifactId>persistence-api</artifactId> <version>1.0.2</version> </dependency> <!--通用Mapper--> <dependency> <groupId>tk.mybatis</groupId> <artifactId>mapper</artifactId> <version>${mapper.version}</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-autoconfigure</artifactId> </dependency> <dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>3.8.0</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>然后是对应的properties文件,记得按照自己的设置修改
记得这里修改数据库的名字以及密码
server.port=5555 # ========================alibaba.druid===================== spring.datasource.type=com.alibaba.druid.pool.DruidDataSource spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:13306/canal_test?useUnicode=true&characterEncoding=utf-8&useSSL=false spring.datasource.username=root spring.datasource.password=abc123 spring.datasource.druid.test-while-idle=false接着主启动类这里用不到,无需配置
下面写业务类
首先先搞连接池
注意修改对应的配置密码以及redis的IP地址
public class RedisUtils { public static final String REDIS_IP_ADDR = "192.168.188.136"; public static final String REDIS_pwd = "abc123"; public static JedisPool jedisPool; static { JedisPoolConfig jedisPoolConfig=new JedisPoolConfig(); jedisPoolConfig.setMaxTotal(20); jedisPoolConfig.setMaxIdle(10); jedisPool=new JedisPool(jedisPoolConfig,REDIS_IP_ADDR,6379,10000,REDIS_pwd); } public static Jedis getJedis() throws Exception { if(null!=jedisPool){ return jedisPool.getResource(); } throw new Exception("Jedispool is not ok"); } }最后就是业务类了
public class RedisCanalClientExample { public static final Integer _60SECONDS = 60; public static final String REDIS_IP_ADDR = "192.168.111.185"; private static void redisInsert(List<Column> columns) { JSONObject jsonObject = new JSONObject(); for (Column column : columns) { System.out.println(column.getName() + " : " + column.getValue() + " update=" + column.getUpdated()); jsonObject.put(column.getName(),column.getValue()); } if(columns.size() > 0) { try(Jedis jedis = RedisUtils.getJedis()) { jedis.set(columns.get(0).getValue(),jsonObject.toJSONString()); }catch (Exception e){ e.printStackTrace(); } } } private static void redisDelete(List<Column> columns) { JSONObject jsonObject = new JSONObject(); for (Column column : columns) { jsonObject.put(column.getName(),column.getValue()); } if(columns.size() > 0) { try(Jedis jedis = RedisUtils.getJedis()) { jedis.del(columns.get(0).getValue()); }catch (Exception e){ e.printStackTrace(); } } } private static void redisUpdate(List<Column> columns) { JSONObject jsonObject = new JSONObject(); for (Column column : columns) { System.out.println(column.getName() + " : " + column.getValue() + " update=" + column.getUpdated()); jsonObject.put(column.getName(),column.getValue()); } if(columns.size() > 0) { try(Jedis jedis = RedisUtils.getJedis()) { jedis.set(columns.get(0).getValue(),jsonObject.toJSONString()); System.out.println("---------update after: "+jedis.get(columns.get(0).getValue())); }catch (Exception e){ e.printStackTrace(); } } } public static void printEntry(List<Entry> entrys) { for (Entry entry : entrys) { if (entry.getEntryType() == EntryType.TRANSACTIONBEGIN || entry.getEntryType() == EntryType.TRANSACTIONEND) { continue; } RowChange rowChage = null; try { //获取变更的row数据 rowChage = RowChange.parseFrom(entry.getStoreValue()); } catch (Exception e) { throw new RuntimeException("ERROR ## parser of eromanga-event has an error,data:" + entry.toString(),e); } //获取变动类型 EventType eventType = rowChage.getEventType(); System.out.println(String.format("================> binlog[%s:%s] , name[%s,%s] , eventType : %s", entry.getHeader().getLogfileName(), entry.getHeader().getLogfileOffset(), entry.getHeader().getSchemaName(), entry.getHeader().getTableName(), eventType)); for (RowData rowData : rowChage.getRowDatasList()) { if (eventType == EventType.INSERT) { redisInsert(rowData.getAfterColumnsList()); } else if (eventType == EventType.DELETE) { redisDelete(rowData.getBeforeColumnsList()); } else {//EventType.UPDATE redisUpdate(rowData.getAfterColumnsList()); } } } } public static void main(String[] args) { System.out.println("---------O(∩_∩)O哈哈~ initCanal() main方法-----------"); //================================= // 创建链接canal服务端 CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress(REDIS_IP_ADDR, 11111), "example", "", ""); int batchSize = 1000; //空闲空转计数器 int emptyCount = 0; System.out.println("---------------------canal init OK,开始监听mysql变化------"); try { connector.connect(); //connector.subscribe(".*\\..*"); connector.subscribe("bigdata.t_user"); connector.rollback(); int totalEmptyCount = 10 * _60SECONDS; while (emptyCount < totalEmptyCount) { System.out.println("我是canal,每秒一次正在监听:"+ UUID.randomUUID().toString()); Message message = connector.getWithoutAck(batchSize); // 获取指定数量的数据 long batchId = message.getId(); int size = message.getEntries().size(); if (batchId == -1 || size == 0) { emptyCount++; try { TimeUnit.SECONDS.sleep(1); } catch (InterruptedException e) { e.printStackTrace(); } } else { //计数器重新置零 emptyCount = 0; printEntry(message.getEntries()); } connector.ack(batchId); // 提交确认 // connector.rollback(batchId); // 处理失败, 回滚数据 } System.out.println("已经监听了"+totalEmptyCount+"秒,无任何消息,请重启重试......"); } finally { connector.disconnect(); } } }此时我们修改mysql,redis就会自动做同步,原因就是我们在这里打日志的时候也进行了redis的回写操作,大家可以在业务类中很容易的发现
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