springboot多數(shù)據(jù)源配置及切換的示例代碼詳解

更新時(shí)間：2020年09月21日 08:35:23 作者：code2roc

這篇文章主要介紹了springboot多數(shù)據(jù)源配置及切換,本文通過實(shí)例代碼給大家介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或工作具有一定的參考借鑒價(jià)值，需要的朋友可以參考下

注：本文的多數(shù)據(jù)源配置及切換的實(shí)現(xiàn)方法是，在框架中封裝，具體項(xiàng)目中配置及使用，也適用于多模塊項(xiàng)目

配置文件數(shù)據(jù)源讀取

通過springboot的Envioment和Binder對(duì)象進(jìn)行讀取，無需手動(dòng)聲明DataSource的Bean

yml數(shù)據(jù)源配置格式如下:

spring:
 datasource:
 master:
  type: com.alibaba.druid.pool.DruidDataSource
  driverClassName: com.mysql.cj.jdbc.Driver
  url: jdbc:mysql://localhost:3306/main?
useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&serverTimezone=Asia/Shanghai
  username: root
  password: 11111
 cluster:
  - key: db1
  type: com.alibaba.druid.pool.DruidDataSource
  driverClassName: com.mysql.cj.jdbc.Driver
  url: jdbc:mysql://localhost:3306/haopanframetest_db1?
useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&serverTimezone=Asia/Shanghai
  username: root
  password: 11111
  - key: db2
  type: com.alibaba.druid.pool.DruidDataSource
  driverClassName: com.mysql.cj.jdbc.Driver
  url: jdbc:mysql://localhost:3306/haopanframetest_db2?
useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&serverTimezone=Asia/Shanghai
  username: root
  password: 11111

master為主數(shù)據(jù)庫必須配置，cluster下的為從庫，選擇性配置

獲取配置文件信息代碼如下

@Autowired
 private Environment env;
 @Autowired
 private ApplicationContext applicationContext;
 private Binder binder;
 
 binder = Binder.get(env);
 List<Map> configs = binder.bind("spring.datasource.cluster", Bindable.listOf(Map.class)).get();
   for (int i = 0; i < configs.size(); i++) {
    config = configs.get(i);
    String key = ConvertOp.convert2String(config.get("key"));
    String type = ConvertOp.convert2String(config.get("type"));
    String driverClassName = ConvertOp.convert2String(config.get("driverClassName"));
    String url = ConvertOp.convert2String(config.get("url"));
    String username = ConvertOp.convert2String(config.get("username"));
    String password = ConvertOp.convert2String(config.get("password"));
   }

動(dòng)態(tài)加入數(shù)據(jù)源

定義獲取數(shù)據(jù)源的Service，具體項(xiàng)目中進(jìn)行實(shí)現(xiàn)

public interface ExtraDataSourceService {
 List<DataSourceModel> getExtraDataSourc();
}

獲取對(duì)應(yīng)Service的所有實(shí)現(xiàn)類進(jìn)行調(diào)用

 private List<DataSourceModel> getExtraDataSource(){
  List<DataSourceModel> dataSourceModelList = new ArrayList<>();
  Map<String, ExtraDataSourceService> res =
applicationContext.getBeansOfType(ExtraDataSourceService.class);
  for (Map.Entry en :res.entrySet()) {
   ExtraDataSourceService service = (ExtraDataSourceService)en.getValue();
   dataSourceModelList.addAll(service.getExtraDataSourc());
  }
  return dataSourceModelList;
 }

通過代碼進(jìn)行數(shù)據(jù)源注冊

主要是用過繼承類AbstractRoutingDataSource，重寫setTargetDataSources/setDefaultTargetDataSource方法

// 創(chuàng)建數(shù)據(jù)源
 public boolean createDataSource(String key, String driveClass, String url, String username, String password, String databasetype) {
  try {
   try { // 排除連接不上的錯(cuò)誤
    Class.forName(driveClass);
    DriverManager.getConnection(url, username, password);// 相當(dāng)于連接數(shù)據(jù)庫
   } catch (Exception e) {
    return false;
   }
   @SuppressWarnings("resource")
   DruidDataSource druidDataSource = new DruidDataSource();
   druidDataSource.setName(key);
   druidDataSource.setDriverClassName(driveClass);
   druidDataSource.setUrl(url);
   druidDataSource.setUsername(username);
   druidDataSource.setPassword(password);
   druidDataSource.setInitialSize(1); //初始化時(shí)建立物理連接的個(gè)數(shù)。初始化發(fā)生在顯示調(diào)用init方法，或者第一次getConnection時(shí)
   druidDataSource.setMaxActive(20); //最大連接池?cái)?shù)量
   druidDataSource.setMaxWait(60000); //獲取連接時(shí)最大等待時(shí)間，單位毫秒。當(dāng)鏈接數(shù)已經(jīng)達(dá)到了最大鏈接數(shù)的時(shí)候，應(yīng)用如果還要獲取鏈接就會(huì)出現(xiàn)等待的現(xiàn)象，等待鏈接釋放并回到鏈接池，如果等待的時(shí)間過長就應(yīng)該踢掉這個(gè)等待，不然應(yīng)用很可能出現(xiàn)雪崩現(xiàn)象
   druidDataSource.setMinIdle(5); //最小連接池?cái)?shù)量
   String validationQuery = "select 1 from dual";
   druidDataSource.setTestOnBorrow(true); //申請(qǐng)連接時(shí)執(zhí)行validationQuery檢測連接是否有效，這里建議配置為TRUE，防止取到的連接不可用
   druidDataSource.setTestWhileIdle(true);//建議配置為true，不影響性能，并且保證安全性。申請(qǐng)連接的時(shí)候檢測，如果空閑時(shí)間大于timeBetweenEvictionRunsMillis，執(zhí)行validationQuery檢測連接是否有效。
   druidDataSource.setValidationQuery(validationQuery); //用來檢測連接是否有效的sql，要求是一個(gè)查詢語句。如果validationQuery為null，testOnBorrow、testOnReturn、testWhileIdle都不會(huì)起作用。
   druidDataSource.setFilters("stat");//屬性類型是字符串，通過別名的方式配置擴(kuò)展插件，常用的插件有：監(jiān)控統(tǒng)計(jì)用的filter:stat日志用的filter:log4j防御sql注入的filter:wall
   druidDataSource.setTimeBetweenEvictionRunsMillis(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
   druidDataSource.setMinEvictableIdleTimeMillis(180000); //配置一個(gè)連接在池中最小生存的時(shí)間，單位是毫秒，這里配置為3分鐘180000
   druidDataSource.setKeepAlive(true); //打開druid.keepAlive之后，當(dāng)連接池空閑時(shí)，池中的minIdle數(shù)量以內(nèi)的連接，空閑時(shí)間超過minEvictableIdleTimeMillis，則會(huì)執(zhí)行keepAlive操作，即執(zhí)行druid.validationQuery指定的查詢SQL，一般為select * from dual，只要minEvictableIdleTimeMillis設(shè)置的小于防火墻切斷連接時(shí)間，就可以保證當(dāng)連接空閑時(shí)自動(dòng)做?；顧z測，不會(huì)被防火墻切斷
   druidDataSource.setRemoveAbandoned(true); //是否移除泄露的連接/超過時(shí)間限制是否回收。
   druidDataSource.setRemoveAbandonedTimeout(3600); //泄露連接的定義時(shí)間(要超過最大事務(wù)的處理時(shí)間)；單位為秒。這里配置為1小時(shí)
   druidDataSource.setLogAbandoned(true); //移除泄露連接發(fā)生是是否記錄日志
   druidDataSource.init();
   this.dynamicTargetDataSources.put(key, druidDataSource);
   setTargetDataSources(this.dynamicTargetDataSources);// 將map賦值給父類的TargetDataSources
   super.afterPropertiesSet();// 將TargetDataSources中的連接信息放入resolvedDataSources管理
   log.info(key+"數(shù)據(jù)源初始化成功");
   //log.info(key+"數(shù)據(jù)源的概況："+druidDataSource.dump());
   return true;
  } catch (Exception e) {
   log.error(e + "");
   return false;
  }
 }

通過切面注解統(tǒng)一切換

定義注解

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE, ElementType.PARAMETER})
@Documented
public @interface TargetDataSource {
 String value() default "master"; //該值即key值
}

定義基于線程的切換類

public class DBContextHolder {
 private static Logger log = LoggerFactory.getLogger(DBContextHolder.class);
 // 對(duì)當(dāng)前線程的操作-線程安全的
 private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
 
 // 調(diào)用此方法，切換數(shù)據(jù)源
 public static void setDataSource(String dataSource) {
  contextHolder.set(dataSource);
  log.info("已切換到數(shù)據(jù)源:{}",dataSource);
 }
 
 // 獲取數(shù)據(jù)源
 public static String getDataSource() {
  return contextHolder.get();
 }
 
 // 刪除數(shù)據(jù)源
 public static void clearDataSource() {
  contextHolder.remove();
  log.info("已切換到主數(shù)據(jù)源");
 }
 
}

定義切面

方法的注解優(yōu)先級(jí)高于類注解，一般用于Service的實(shí)現(xiàn)類

@Aspect
@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class DruidDBAspect {
 private static Logger logger = LoggerFactory.getLogger(DruidDBAspect.class);
 @Autowired
 private DynamicDataSource dynamicDataSource;
 
 /**
  * 切面點(diǎn) 指定注解
  * */
 @Pointcut("@annotation(com.haopan.frame.common.annotation.TargetDataSource) " +
   "|| @within(com.haopan.frame.common.annotation.TargetDataSource)")
 public void dataSourcePointCut() {
 
 }
 
 /**
  * 攔截方法指定為 dataSourcePointCut
  * */
 @Around("dataSourcePointCut()")
 public Object around(ProceedingJoinPoint point) throws Throwable {
  MethodSignature signature = (MethodSignature) point.getSignature();
  Class targetClass = point.getTarget().getClass();
  Method method = signature.getMethod();
 
  TargetDataSource targetDataSource = (TargetDataSource)targetClass.getAnnotation(TargetDataSource.class);
  TargetDataSource methodDataSource = method.getAnnotation(TargetDataSource.class);
  if(targetDataSource != null || methodDataSource != null){
   String value;
   if(methodDataSource != null){
    value = methodDataSource.value();
   }else {
    value = targetDataSource.value();
   }
   DBContextHolder.setDataSource(value);
   logger.info("DB切換成功，切換至{}",value);
  }
 
  try {
   return point.proceed();
  } finally {
   logger.info("清除DB切換");
   DBContextHolder.clearDataSource();
  }
 }
}

分庫切換

開發(fā)過程中某個(gè)庫的某個(gè)表做了拆分操作，相同的某一次數(shù)據(jù)庫操作可能對(duì)應(yīng)到不同的庫，需要對(duì)方法級(jí)別進(jìn)行精確攔截，可以定義一個(gè)業(yè)務(wù)層面的切面，規(guī)定每個(gè)方法必須第一個(gè)參數(shù)為dbName，根據(jù)具體業(yè)務(wù)找到對(duì)應(yīng)的庫傳參

@Around("dataSourcePointCut()")
 public Object around(ProceedingJoinPoint point) throws Throwable {
  MethodSignature signature = (MethodSignature) point.getSignature();
  Class targetClass = point.getTarget().getClass();
  Method method = signature.getMethod();
 
  ProjectDataSource targetDataSource =
(ProjectDataSource)targetClass.getAnnotation(ProjectDataSource.class);
  ProjectDataSource methodDataSource = method.getAnnotation(ProjectDataSource.class);
  String value = "";
  if(targetDataSource != null || methodDataSource != null){
   //獲取方法定義參數(shù)
   DefaultParameterNameDiscoverer discover = new DefaultParameterNameDiscoverer();
   String[] parameterNames = discover.getParameterNames(method);
   //獲取傳入目標(biāo)方法的參數(shù)
   Object[] args = point.getArgs();
   for (int i=0;i<parameterNames.length;i++){
    String pName = parameterNames[i];
    if(pName.toLowerCase().equals("dbname")){
     value = ConvertOp.convert2String(args[i]);
    }
   }
   if(!StringUtil.isEmpty(value)){
    DBContextHolder.setDataSource(value);
    logger.info("DB切換成功，切換至{}",value);
   }
  }
 
  try {
   return point.proceed();
  } finally {
   if(!StringUtil.isEmpty(value)){
    logger.info("清除DB切換");
    DBContextHolder.clearDataSource();
   }
 
  }
 }

相關(guān)代碼

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