DataSourcePoolMetadata (Spring Boot API)

所有已知实现类:
AbstractDataSourcePoolMetadata, CommonsDbcp2DataSourcePoolMetadata, CommonsDbcpDataSourcePoolMetadata, HikariDataSourcePoolMetadata, TomcatDataSourcePoolMetadata
```
public interface DataSourcePoolMetadata
```
Provides access meta-data that is commonly available from most pooled DataSource implementations.
从以下版本开始:
1.2.0

方法概要

所有方法实例方法抽象方法
修饰符和类型	方法	说明
`Integer`	`getActive()`	Return the current number of active connections that have been allocated from the data source or `null` if that information is not available.
`Integer`	`getMax()`	Return the maximum number of active connections that can be allocated at the same time or `-1` if there is no limit.
`Integer`	`getMin()`	Return the minimum number of idle connections in the pool or `null` if that information is not available.
`Float`	`getUsage()`	Return the usage of the pool as value between 0 and 1 (or -1 if the pool is not limited).
`String`	`getValidationQuery()`	Return the query to use to validate that a connection is valid or `null` if that information is not available.

- 方法详细资料
  - getUsage
```
Float getUsage()
```
    Return the usage of the pool as value between 0 and 1 (or -1 if the pool is not limited).
    1 means that the maximum number of connections have been allocated
    0 means that no connection is currently active
    -1 means there is not limit to the number of connections that can be allocated
    This may also return null if the data source does not provide the necessary information to compute the poll usage.
    返回:
    the usage value or null
  - getActive
```
Integer getActive()
```
    Return the current number of active connections that have been allocated from the data source or null if that information is not available.
    返回:
    the number of active connections or null
  - getMax
```
Integer getMax()
```
    Return the maximum number of active connections that can be allocated at the same time or -1 if there is no limit. Can also return null if that information is not available.
    返回:
    the maximum number of active connections or null
  - getMin
```
Integer getMin()
```
    Return the minimum number of idle connections in the pool or null if that information is not available.
    返回:
    the minimum number of active connections or null
  - getValidationQuery
```
String getValidationQuery()
```
    Return the query to use to validate that a connection is valid or null if that information is not available.
    返回:
    the validation query or null