SpringBoot多資料來源切換實現程式碼(Mybaitis)

2022-04-12 13:00:05

前言

但是在實際業務場景中，資料量迅速增長，一個庫一個表已經滿足不了我們的需求的時候，我們就會考慮分庫分表的操作，在springboot中如何實現多資料來源，動態資料來源切換，讀寫分離等操作。當你看到這篇檔案那麼你幸運了,下面直接提供終極通用版程式碼

如果是非Mybaitis的那麼可以進行參照,原理都差不多

組態檔(YML)

spring:
  datasource:
    default-db-key: voidme
    multi-db:
      - voidme:
          driver-class-name: com.mysql.cj.jdbc.Driver
          username: root
          password: root
          url: jdbc:mysql://192.168.42.153:3306/voidme?characterEncoding=utf8&autoReconnect=true&failOverReadOnly=false&maxReconnects=10&useSSL=false
      - xcdef:
          driver-class-name: com.mysql.cj.jdbc.Driver
          username: root
          password: root
          url: jdbc:mysql://192.168.42.153:3306/xcdef?characterEncoding=utf8&autoReconnect=true&failOverReadOnly=false&maxReconnects=10&useSSL=false


mybatis:
  #1.classpath：只會到你的classes路徑中查詢找檔案。
  #2.classpath*：不僅會到classes路徑，還包括jar檔案中(classes路徑)進行查詢。
  mapper-locations: classpath*:/mapper/**/*Mapper.xml    # mapper對映檔案位置
  type-aliases-package: com.**.entity    # 實體類所在的位置
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl   #用於控制檯列印sql語句
    map-underscore-to-camel-case: true #開啟將帶有下劃線的表欄位 對映為駝峰格式的實體類屬性

核心程式碼

DynamicDataSource

這個類用於獲取資料來源的(核心)

package com.dynamicdatadource.dynamic;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

public class DynamicDataSource extends AbstractRoutingDataSource {

    @Value("${spring.datasource.default-db-key}")
    private String defaultDbKey;

    @Override
    protected Object determineCurrentLookupKey() {
        String currentDb = DynamicDataSourceService.currentDb();
        if (currentDb == null) {
            return defaultDbKey;
        }
        return currentDb;
    }
}

DynamicDataSourceService

這個類是資料來源切換工具,我們做了執行緒隔離了所以不用擔心多執行緒資料來源會混亂的問題

package com.dynamicdatadource.dynamic;

import com.application.ApplicationContextProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.jdbc.DataSourceBuilder;

import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

public class DynamicDataSourceService  {
    private static final Logger log = LoggerFactory.getLogger(DynamicDataSourceService.class);

    private static final Map<Object, Object> dataSources = new HashMap<>();
    private static final ThreadLocal<String> dbKeys = ThreadLocal.withInitial(() -> null);

    /**
     * 動態新增一個資料來源
     *
     * @param name       資料來源的key
     * @param dataSource 資料來源物件
     */
    public static void addDataSource(String name, DataSource dataSource) {
        DynamicDataSource dynamicDataSource = ApplicationContextProvider.getApplicationContext().getBean(DynamicDataSource.class);
        dataSources.put(name, dataSource);
        dynamicDataSource.setTargetDataSources(dataSources);
        dynamicDataSource.afterPropertiesSet();
        log.info("新增了資料來源:{}",name);
    }

    /**
     * @param name   資料來源的key
     * @param driverClassName  驅動
     * @param url     資料庫連線地址
     * @param username   資料庫賬戶
     * @param password   資料庫密碼
     */
    public static void addDataSource(String name, String driverClassName,String url,String username,String password) {
        DataSourceBuilder<?> builder = DataSourceBuilder.create();
        builder.driverClassName(driverClassName);
        builder.username(username);
        builder.password(password);
        builder.url(url);
        addDataSource(name,builder.build());
        log.info("新增了資料來源:{}",name);
    }
    /**
     * 切換資料來源
     */
    public static void switchDb(String dbKey) {
        dbKeys.set(dbKey);
    }

    /**
     * 重置資料來源(切換為預設的資料來源)
     */
    public static void resetDb() {
        dbKeys.remove();
    }

    /**
     * 獲取當前資料來源的key
     */
    public static String currentDb() {
        return dbKeys.get();
    }
}

DynamicDataSourceConfig

將資料來源設定到springboot中和初始化Mybaitis設定

package com.dynamicdatadource.dynamic;

import lombok.Data;
import org.apache.ibatis.logging.Log;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

@Configuration
@ConfigurationProperties(prefix = "mybatis")
@Data
public class DynamicDataSourceConfig {

    private String mapperLocations;
    private String typeAliasesPackage;
    @Data
    public class MybatisConfiguration{
        private String logImpl;
        private boolean mapUnderscoreToCamelCase;
    }
    private  MybatisConfiguration configuration=new MybatisConfiguration();


    /**
     * 動態資料來源
     */
    @Bean
    public DynamicDataSource dynamicDataSource() {
        DynamicDataSource dataSource = new DynamicDataSource();
        Map<Object, Object> targetDataSources = new HashMap<>();
        dataSource.setTargetDataSources(targetDataSources);
        return dataSource;
    }

    /**
     * 對談工廠Mybaitis
     */
    @Bean
    public SqlSessionFactoryBean sqlSessionFactoryBean() throws IOException, ClassNotFoundException {
        org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
        configuration.setMapUnderscoreToCamelCase(this.configuration.isMapUnderscoreToCamelCase()); //開啟駝峰命名
        configuration.setLogImpl((Class<? extends Log>) Class.forName(this.configuration.getLogImpl())); //控制檯列印sql紀錄檔
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dynamicDataSource());
        sqlSessionFactoryBean.setConfiguration(configuration);
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources(mapperLocations));
        sqlSessionFactoryBean.setTypeAliasesPackage(typeAliasesPackage);
        return sqlSessionFactoryBean;
    }

    /**
     * 事務管理器
     */
    @Bean
    public PlatformTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dynamicDataSource());
    }
}

載入YML資料庫設定類

package com.dynamicdatadource.config;

import com.dynamicdatadource.dynamic.DynamicDataSourceService;
import lombok.Data;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.sql.DataSource;
import java.util.List;
import java.util.Map;
import java.util.Set;

@Component
@Data
@ConfigurationProperties(prefix = "spring.datasource")
public class YmlDataSourceProvider  {

    private List<Map<String, DataSourceProperties>> multiDb;

    private DataSource buildDataSource(DataSourceProperties prop) {
        DataSourceBuilder<?> builder = DataSourceBuilder.create();
        builder.driverClassName(prop.getDriverClassName());
        builder.username(prop.getUsername());
        builder.password(prop.getPassword());
        builder.url(prop.getUrl());
        return builder.build();
    }

    public void initDataSource() {
        multiDb.forEach(map -> {
            Set<String> keys = map.keySet();
            keys.forEach(key -> {
                DataSourceProperties properties = map.get(key);
                DataSource dataSource = buildDataSource(properties);
                DynamicDataSourceService.addDataSource(key, dataSource);
            });
        });
    }

    //在建構函式之後執行
    @PostConstruct
    public void init() {
        initDataSource();
    }
}

aop切換

package com.dynamicdatadource.aop;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.METHOD,ElementType.TYPE})//作用:方法和類
@Retention(RetentionPolicy.RUNTIME)
public @interface DynamicDataSourceAnno {
    String key() default "";
}

package com.dynamicdatadource.aop;
import com.dynamicdatadource.dynamic.DynamicDataSourceService;
import org.apache.commons.lang.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;

// 用於單獨的請求或者類進行切換資料庫
@Aspect
@Component
public class DynamicDataSourceAspect {
    @Pointcut("@annotation(com.dynamicdatadource.aop.DynamicDataSourceAnno)")
    public void dynamicDataSourceAnno() {
    }

    @Around("dynamicDataSourceAnno()")
    public Object DynamicDataSourceAspectAroundAnno(ProceedingJoinPoint joinPoint) {
        Object object = null;
        try {
            MethodSignature signature = (MethodSignature)joinPoint.getSignature();
            DynamicDataSourceAnno dynamicDataSourceAnno  = signature.getMethod().getAnnotation(DynamicDataSourceAnno.class);
            String key = dynamicDataSourceAnno.key();
            if (StringUtils.isNotBlank(key)) {
                //切換為指定資料庫
                DynamicDataSourceService.switchDb(key);
            }
            object = joinPoint.proceed();
        } catch (Throwable e) {
            e.printStackTrace();
        }finally {
            //還原為預設設定
            DynamicDataSourceService.resetDb();
        }
        return object;
    }
    // 還可以擴充套件包路徑切換
}

效果

執行程式之後,就會將資料來源加入到資料來源列表中了

擴充套件

MysqlDataSourceInitialize

從資料庫中將設定資訊查詢出來,然後動態新增到資料來源列表中

package com.dao.config;

import com.dao.DatasourceDao;
import com.dynamicdatadource.aop.DynamicDataSourceAnno;
import com.dynamicdatadource.dynamic.DynamicDataSourceService;
import com.entity.DataSourceEneity;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.sql.DataSource;
import java.util.List;

//從資料庫中查詢出全部的資料來源,新增到資料來源容器中

/**
 * 表結構如下:
 *
 * CREATE TABLE `t_datasource` (
 *   `id` int(11) NOT NULL,
 *   `key` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '繫結的key,用於資料來源的切換',
 *   `url` text CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '資料庫連線地址',
 *   `username` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '資料庫使用者名稱',
 *   `password` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '資料庫密碼',
 *   `driverClassName` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '資料庫驅動',
 *   `type` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '資料庫型別:  mysql ,oracle,..',
 *   `state` int(2) NOT NULL COMMENT '是否可用: 1可用 ,2不可用',
 *   PRIMARY KEY (`id`),
 *   UNIQUE KEY `key` (`key`)
 * ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
 *
 * 上表要放入到預設資料來源中的資料庫裡才行
 */
@Component
public class MysqlDataSourceInitialize implements ApplicationRunner  {

    @Autowired
    private DatasourceDao datasourceDao;

    //專案啟動後執行初始化資料來源
    @Override
    public void run(ApplicationArguments args) throws Exception {
        try {
            List<DataSourceEneity> dataSources = datasourceDao.getDataSources();
            for (DataSourceEneity dataSource : dataSources) {
                DynamicDataSourceService.addDataSource(dataSource.getKey(),dataSource.getDataSource());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

DataSourceEneity實體類

@Data
public class DataSourceEneity {
    private int id;
    private String key;
    private String url;
    private String username;
    private String password;
    private String driverClassName;
    private String type;
    private int state;

    public  DataSource getDataSource() {
        DataSourceBuilder<?> builder = DataSourceBuilder.create();
        builder.driverClassName(driverClassName);
        builder.username(username);
        builder.password(password);
        builder.url(url);
        return  builder.build();
    }
}