JDBCConnectionException “无法获取 JDBC 连接” 与 spring 引导

Question

当我使用Japser报告生成报告时，我的Spring Boot工作正常。

我面临的问题是应用程序抛出Hibernate异常：

无法获取JDBC连接

在我多次生成报告后，我得到了这个错误。

1 running delayed actions on {type: MASTER, group: null, band: 0}
2018-09-20 14:27:55.536 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.fill.JRBaseFiller           : Fill 1: ended
2018-09-20 14:27:55.536 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.fill.JRFillDataset          : Fill 1: closing query executer
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block DEVANAGARI
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block BENGALI
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block TELUGU
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block TAMIL
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block GUJARATI
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block KANNADA
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block MALAYALAM
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block ORIYA
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block GURMUKHI
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block SINHALA
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block TIBETAN
2018-09-20 14:27:55.539 DEBUG 46148 --- [ XNIO-2 task-27] 
n.s.j.engine.export.JRPdfExporter        : glyph renderer block KHMER
2018-09-20 14:28:25.549  WARN 46148 --- [ XNIO-2 task-27] 
o.h.engine.jdbc.spi.SqlExceptionHelper   : SQL Error: 0, SQLState: null
2018-09-20 14:28:25.550 ERROR 46148 --- [ XNIO-2 task-27] 
o.h.engine.jdbc.spi.SqlExceptionHelper   : HikariPool-1 - Connection is not 
available, request timed out after 30000ms.
2018-09-20 14:28:25.556 ERROR 46148 --- [ XNIO-2 task-27] 
c.n.xx.aop.logging.LoggingAspect    : Exception in 
com.xx.xx.web.rest.GrueResource.generateRapportGrue() with cause = 
'org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC 
Connection' and exception = 'Could not open JPA EntityManager for 
transaction; nested exception is 
org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC 
Connection'

org.springframework.transaction.CannotCreateTransactionException: Could not 
open JPA EntityManager for transaction; nested exception is 
org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC 
Connection

Answer 1

当我使用 jasper 报告时，我确实每 2 天都会遇到同样的问题，并最终通过正确的理解修复了它，因为当我们使用基于查询的报告时，我们有责任关闭我们自己的数据源的连接，以便它返回到池中并可供下次使用。你必须处理多件事 1-从数据源获取连接

DataSourceUtils.getConnection(ds);

2-在任何情况下都必须关闭数据源连接：最好在最终块中关闭它，以便在异常情况下连接不会保持打开状态。

finally{closeConnection(con,dataSource);}
public void closeConnection(Connection con,DataSource ds) {

 if (con != null) {
DataSourceUtils.releaseConnection(con, ds);
 }
}

3-应用程序中的更改。属性文件

spring.datasource.hikari.connectionTimeout=30000   
spring.datasource.hikari.idleTimeout=600000          
spring.datasource.hikari.maxLifetime=1800000      
spring.datasource.hikari.maximumPoolSize=30

Answer 2

你失去了联系。

尝试将Hikari连接池设置为更大的数字：

spring.datasource.hikari.maximum-pool-size=10