SpringBoot多数据源unsatisfied dependency expressed through method 'entityManagerFactoryBuilder...

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本来的项目（基于SpringBoot 2.0.5-RELEASE）集成了JPA、mybatis的注解、XML方式访问DB。
后面集成多数据源的时候启动SpringBoot时出现了如下错误：

ERROR 32320 — [main] com.zaxxer.hikari.HikariConfig : HikariPool-1 - jdbcUrl is required with driverClassName.

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name ‘entityManagerFactory’ defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Unsatisfied dependency expressed through method ‘entityManagerFactory’ parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name ‘entityManagerFactoryBuilder’ defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Unsatisfied dependency expressed through method ‘entityManagerFactoryBuilder’ parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘jpaVendorAdapter’ defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.jpa.JpaVendorAdapter]: Factory method ‘jpaVendorAdapter’ threw exception; nested exception is java.lang.IllegalArgumentException: jdbcUrl is required with driverClassName.
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:732)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:474)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1247)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1096)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:535)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1089)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:859)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:333)
at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:139)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117)
… 24 more

后来查看了源码，流程如下：

@Bean(name = "test1DataSource")
    @ConfigurationProperties(prefix = "spring.datasource")
    @Primary
    public DataSource testDataSource() {
        return DataSourceBuilder.create().build();
    }

进入DataSourceBuilder.create().build()：

public T build() {
		Class<? extends DataSource> type = getType();
		DataSource result = BeanUtils.instantiateClass(type);
		maybeGetDriverClassName();
		bind(result);
		return (T) result;
	}

maybeGetDriverClassName(); 方法：

private void maybeGetDriverClassName() {
		if (!this.properties.containsKey("driverClassName")
				&& this.properties.containsKey("url")) {
			String url = this.properties.get("url");
			String driverClass = DatabaseDriver.fromJdbcUrl(url).getDriverClassName();
			this.properties.put("driverClassName", driverClass);
		}
	}

bind(result) 方法：

private void bind(DataSource result) {
		ConfigurationPropertySource source = new MapConfigurationPropertySource(
				this.properties);
		ConfigurationPropertyNameAliases aliases = new ConfigurationPropertyNameAliases();
		aliases.addAliases("url", "jdbc-url");
		aliases.addAliases("username", "user");
		Binder binder = new Binder(source.withAliases(aliases));
		binder.bind(ConfigurationPropertyName.EMPTY, Bindable.ofInstance(result));
	}

因为springboot首推的连接池使用了HikariCP连接池，GET到这个点， HikariDataSource的获取数据库连接的getConnection方法：

@Override
   public Connection getConnection() throws SQLException
   {
      if (isClosed()) {
         throw new SQLException("HikariDataSource " + this + " has been closed.");
      }

      if (fastPathPool != null) {
         return fastPathPool.getConnection();
      }

      // See http://en.wikipedia.org/wiki/Double-checked_locking#Usage_in_Java
      HikariPool result = pool;
      if (result == null) {
         synchronized (this) {
            result = pool;
            if (result == null) {
               validate();
               LOGGER.info("{} - Starting...", getPoolName());
               try {
                  pool = result = new HikariPool(this);
                  this.seal();
               }
               catch (PoolInitializationException pie) {
                  if (pie.getCause() instanceof SQLException) {
                     throw (SQLException) pie.getCause();
                  }
                  else {
                     throw pie;
                  }
               }
               LOGGER.info("{} - Start completed.", getPoolName());
            }
         }
      }

      return result.getConnection();
   }

HikariConfig的validate方法

public void validate()
   {
      if (poolName == null) {
         poolName = generatePoolName();
      }
      else if (isRegisterMbeans && poolName.contains(":")) {
         throw new IllegalArgumentException("poolName cannot contain ':' when used with JMX");
      }

      // treat empty property as null
      catalog = getNullIfEmpty(catalog);
      connectionInitSql = getNullIfEmpty(connectionInitSql);
      connectionTestQuery = getNullIfEmpty(connectionTestQuery);
      transactionIsolationName = getNullIfEmpty(transactionIsolationName);
      dataSourceClassName = getNullIfEmpty(dataSourceClassName);
      dataSourceJndiName = getNullIfEmpty(dataSourceJndiName);
      driverClassName = getNullIfEmpty(driverClassName);
      jdbcUrl = getNullIfEmpty(jdbcUrl);

      // Check Data Source Options
      if (dataSource != null) {
         if (dataSourceClassName != null) {
            LOGGER.warn("{} - using dataSource and ignoring dataSourceClassName.", poolName);
         }
      }
      else if (dataSourceClassName != null) {
         if (driverClassName != null) {
            LOGGER.error("{} - cannot use driverClassName and dataSourceClassName together.", poolName);
            // NOTE: This exception text is referenced by a Spring Boot FailureAnalyzer, it should not be
            // changed without first notifying the Spring Boot developers.
            throw new IllegalStateException("cannot use driverClassName and dataSourceClassName together.");
         }
         else if (jdbcUrl != null) {
            LOGGER.warn("{} - using dataSourceClassName and ignoring jdbcUrl.", poolName);
         }
      }
      else if (jdbcUrl != null || dataSourceJndiName != null) {
         // ok
      }
      else if (driverClassName != null) {
         LOGGER.error("{} - jdbcUrl is required with driverClassName.", poolName);
         throw new IllegalArgumentException("jdbcUrl is required with driverClassName.");
      }
      else {
         LOGGER.error("{} - dataSource or dataSourceClassName or jdbcUrl is required.", poolName);
         throw new IllegalArgumentException("dataSource or dataSourceClassName or jdbcUrl is required.");
      }

      validateNumerics();

      if (LOGGER.isDebugEnabled() || unitTest) {
         logConfiguration();
      }
   }

这个if分支：

jdbcUrl = getNullIfEmpty(jdbcUrl);


else if (driverClassName != null) {
         LOGGER.error("{} - jdbcUrl is required with driverClassName.", poolName);
         throw new IllegalArgumentException("jdbcUrl is required with driverClassName.");
      }

这里要求DataSource的参数存在 jdbcUrl 、以及driverClassName，而我们的配置是：

spring.datasource.url=jdbc:mysql://localhost:3306/mypydb
spring.datasource.username=root
spring.datasource.password=11111111
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

spring.datasource2.url=jdbc:mysql://localhost:3306/mypydb2
spring.datasource2.username=root
spring.datasource2.password=11111111
spring.datasource2.driver-class-name=com.mysql.jdbc.Driver

所以将url改为 jdbc-url 即可。

spring.datasource.jdbc-url=jdbc:mysql://localhost:3306/mypydb

spring.datasource2.jdbc-url=jdbc:mysql://localhost:3306/mypydb2