Druid數(shù)據(jù)庫多數(shù)據(jù)源

Spring的多數(shù)據(jù)源支持—AbstractRoutingDataSource，AbstractRoutingDataSource定義了抽象的determineCurrentLookupKey方法，子類實現(xiàn)此方法，來確定要使用的數(shù)據(jù)源

Druid 實現(xiàn)多數(shù)據(jù)源支持，核心是Overwrite AbstractRoutingDataSource 的 determineCurrentLookupKey 方法

public abstract class AbstractRoutingDataSource extends AbstractDataSource implements InitializingBean {
	 protected DataSource determineTargetDataSource() {
		Assert.notNull(this.resolvedDataSources, "DataSource router not initialized");
		Object lookupKey = determineCurrentLookupKey();
		DataSource dataSource = this.resolvedDataSources.get(lookupKey);
		if (dataSource == null && (this.lenientFallback || lookupKey == null)) {
			dataSource = this.resolvedDefaultDataSource;
		}
		if (dataSource == null) {
			throw new IllegalStateException("Cannot determine target DataSource for 	             lookup key [" + lookupKey + "]");
		}
		return dataSource;
	}

        // 確定當(dāng)前要使用的數(shù)據(jù)源
        protected abstract Object determineCurrentLookupKey();
}

配置多數(shù)據(jù)源

以springboot框架為基礎(chǔ)使用aop注解的方式依賴Druid配置多數(shù)據(jù)源

1.添加依賴

<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
	
		<!-- aop注解實現(xiàn)aspectjweaver依賴 -->
		<dependency>
			<groupId>org.aspectj</groupId>
			<artifactId>aspectjweaver</artifactId>
			<version>1.9.6</version>
		</dependency>
		<!-- mybatis-spring-boot-starter -->
		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>2.1.3</version>
		</dependency>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>8.0.28</version>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<!-- https://mvnrepository.com/artifact/com.alibaba/druid-spring-boot-starter -->
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>druid-spring-boot-starter</artifactId>
			<version>1.2.8</version>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-configuration-processor</artifactId>
			<optional>true</optional>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<version>1.18.12</version>
			<scope>provided</scope>
		</dependency>

2.配置Druid屬性

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource
    first:
      url: jdbc:mysql://localhost:3306/***?useUnicode=true&characterEncoding=utf-                  8&serverTimezone=UTC
      username: root
      password: *****
    second:
      enable: true
      url: jdbc:mysql://localhost:3306/***?useUnicode=true&characterEncoding=utf-                 8&serverTimezone=UTC
      username: root
      password: *****
    druid:
      # 初始連接數(shù)
      initialSize: 5
      # 最小連接池數(shù)量
      minIdle: 10
      # 最大連接池數(shù)量
      maxActive: 20
      # 配置獲取連接等待超時的時間
      maxWait: 60000
      # 配置間隔多久才進(jìn)行一次檢測，檢測需要關(guān)閉的空閑連接，單位是毫秒
      timeBetweenEvictionRunsMillis: 60000
      # 配置一個連接在池中最小生存的時間，單位是毫秒
      minEvictableIdleTimeMillis: 300000
      # 配置一個連接在池中最大生存的時間，單位是毫秒
      maxEvictableIdleTimeMillis: 900000
      # 配置檢測連接是否有效
      validationQuery: SELECT 1 FROM DUAL
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      webStatFilter:
        enabled: true
      statViewServlet:
        enabled: true
        # 控制臺管理用戶名和密碼
        login-username: admin
        login-password: 123456
      #配置監(jiān)控統(tǒng)計攔截的filters：stat:監(jiān)控統(tǒng)計、self4j(使用log4j的記得導(dǎo)入log4j的依賴）：日志記錄、          wall：防御sql注入 此處配置不能遺漏服務(wù)sql監(jiān)控臺不能監(jiān)控sql
      filters: stat,wall,log4j2
      filter:
        stat:
          enabled: true
          # 慢SQL記錄
          log-slow-sql: true
          slow-sql-millis: 1000
          merge-sql: true
        wall:
          enabled: true
          config:
            multi-statement-allow: true

3.配置動態(tài)數(shù)據(jù)源

繼承AbstractRoutingDataSource重寫determineCurrentLookupKey()方法

/**
 * 動態(tài)數(shù)據(jù)源
 */
public class DynamicDatesource extends AbstractRoutingDataSource {

    public DynamicDatesource(DataSource dataSource,HashMap<Object, Object> map){
        super.setDefaultTargetDataSource(dataSource);
        super.setTargetDataSources(map);
        super.afterPropertiesSet();
    }

    /**
     * 獲取key指定數(shù)據(jù)源
     * @return
     */
    @Override
    protected Object determineCurrentLookupKey() {
        return DynamicDateSourceCut.getLocal();
    }
}

配置數(shù)據(jù)源

//配置數(shù)據(jù)源
@Configuration
public class DruidConfig {

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.first")
    public DataSource firstDataSource(DruidSourceProperties druidSourceProperties){

        return druidSourceProperties.dataSource(new DruidDataSourceWrapper());
    }
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.second")
    @ConditionalOnProperty(prefix ="spring.datasource.second",name ="enable",havingValue = "true")
    public DataSource secondDataSource(DruidSourceProperties druidSourceProperties){
        return druidSourceProperties.dataSource(new DruidDataSourceWrapper());
    }
    @Bean
    @Primary//在多數(shù)據(jù)源的時候，使用@Primary注解用于指定其中一個作為主數(shù)據(jù)源
    public DynamicDatesource setDymaicDatesource(DataSource firstDataSource){
        HashMap<Object, Object> map = new HashMap<>();
        map.put(DateSourceType.FIRST.name(),firstDataSource);
        setDataSource(map,DateSourceType.SECOND.name(),"secondDataSource");
        return new DynamicDatesource(firstDataSource,map);
    }
    /**
     * 設(shè)置數(shù)據(jù)源
     *
     * @param targetDataSources 備選數(shù)據(jù)源集合
     * @param sourceName 數(shù)據(jù)源名稱
     * @param beanName bean名稱
     */
    public void setDataSource(Map<Object, Object> targetDataSources, String sourceName, 		String beanName){
        try {
            DataSource dataSource = SpringUtils.getBean(beanName);
            targetDataSources.put(sourceName, dataSource);
        } catch (Exception e){

        }
    }
}

4.配置數(shù)據(jù)源切換

package com.example.springboot.data;
/**
*數(shù)據(jù)源切換 保存每個數(shù)據(jù)源指定的lookupKey
*/
public class DynamicDateSourceCut {
    /**
     * 使用ThreadLocal維護(hù)變量，ThreadLocal為每個使用該變量的線程提供獨立的變量副本，
     *  所以每一個線程都可以獨立地改變自己的副本，而不會影響其它線程所對應(yīng)的副本。
     */

    private static ThreadLocal<String> threadLocal=new ThreadLocal<>();

    /**
     * 設(shè)置數(shù)據(jù)源的變量
     */
    public static void setLocal(String local){
        threadLocal.set(local);

    }
    /**
     * 獲得數(shù)據(jù)源的變量
     */
    public static String getLocal(){
        return threadLocal.get();

    }
    /**
     * 清空數(shù)據(jù)源變量
     */
    public static void clearLocl() {
        threadLocal.remove();
    }
}

5.定義aop切面實現(xiàn)

/**
 * 定義數(shù)據(jù)源切面
 */
@Aspect
@Component
public class DateSourceAspect {

    private static final Logger log= LoggerFactory.getLogger(DateSourceAspect.class);

    /**
     * 定義切點  使用注解
     * @within類注解
     * @annotation方法注解
     */
    @Pointcut("@annotation(com.example.springboot.aspect.DateSource)"+
             "||@within(com.example.springboot.aspect.DateSource)")
    public void PintCut(){

    }
    /**
     * 通知使用環(huán)繞的通知方法
     */
    @Around("PintCut()")
    public Object ResovePoint(ProceedingJoinPoint point) throws Throwable {
        //獲取注解
        DateSource dateSource = getDateSource(point);
        if (dateSource!=null){
            DynamicDateSourceCut.setLocal(dateSource.value().name());
        }
        try {
            //執(zhí)行方法
           return point.proceed();
        } finally {
            // 銷毀數(shù)據(jù)源 在執(zhí)行方法之后
            DynamicDateSourceCut.clearLocl();
        }

    }

    /**
     * 獲取注解
     */
    protected DateSource getDateSource(ProceedingJoinPoint point){
        MethodSignature signature = (MethodSignature) point.getSignature();
        //獲取方法或方法類型上的注解
        DateSource annotation;
        //獲取class類型上注解
        annotation=AnnotationUtils.findAnnotation(signature.getDeclaringType(),DateSource.class);
        if (annotation==null){
            annotation = AnnotationUtils.findAnnotation(signature.getMethod(), DateSource.class);
        }
        return annotation;
    }
}

定義的注解和注解值文章來源地址http://www.zghlxwxcb.cn/news/detail-515391.html

/**
 * 定義注解
 */
@Target({ElementType.TYPE,ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DateSource {
    DateSourceType value()default DateSourceType.FIRST;
}


/**
*使用枚舉定義注解的值
*/

public enum DateSourceType {
    //默認(rèn)數(shù)據(jù)庫
    FIRST,
    SECOND;
}

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