Spring JDBC 模板：queryforlist 不关闭数据库连接？

Question

在 NamedParameterJdbcTemplate 用于检索记录列表的 Wildfly Web 应用程序中有后台作业，我有一个数据库连接泄漏阻止作业在一段时间后工作，CannotGetJdbcConnectionException。

在监控了 sql 请求的一部分之后，这是我的发现。对于这段简单的代码：

String sqlselectreq = 
    "SELECT * " + 
    "FROM systemedpdfdb.documents " +
    "WHERE state=-3 AND closing_date IS null";

NamedParameterJdbcTemplate namedParameterJdbcTemplate = new  
    NamedParameterJdbcTemplate(this.getDataSource());

Map<String, Object> namedParameters = new HashMap<String, Object>();
// namedParameters.put("param_name_here", param_value_here);
List<Map<String, Object>> queryres =  
    namedParameterJdbcTemplate.queryForList(sqlselectreq, namedParameters);

if (!(queryres == null || queryres.isEmpty())) {
    for (Map<String, Object> queryrec : queryres) {
       ....
    }
} else {
    return new Result(this, Result.CodeCategory.NOERROR, 
        Result.Type.TEXT, "NOTHING TO DO".getBytes(), ident);

}

我有以下痕迹，其中我们可以看到没有关闭的无用的最后一个 getConnection。

2017-05-11 15:37:00,031 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [DataSource] getConnection()
2017-05-11 15:37:00,281 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [Connection] prepareStatement(SELECT * FROM systemedpdfdb.documents WHERE state=-3 and closing_date is null)
2017-05-11 15:37:00,297 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [PreparedStatement] executeQuery()
2017-05-11 15:37:00,312 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [ResultSet] next()
2017-05-11 15:37:00,312 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [ResultSet] close()
2017-05-11 15:37:00,312 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [PreparedStatement] isClosed()
2017-05-11 15:37:00,328 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [PreparedStatement] close()
2017-05-11 15:37:00,328 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [Connection] isClosed()
2017-05-11 15:37:00,328 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [Connection] close()
2017-05-11 15:37:00,328 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [DataSource] getConnection()
2017-05-11 15:37:00,328 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [Connection] getMetaData()

正常吗？还是我误用了 Spring Jdbc 模板？

提前致谢

大卫·L.

Answer 1

实际的数据库连接由您的数据源实现包装。您使用的是什么 DataSource 实现？

在 Web 应用程序中，您应该（总是？）使用提供已建立连接池（也称为连接池）的数据源。有几个优秀的数据库连接池实现可用。例如，DBCP、c3p0 和 Heroku。

此外，如果您使用 Spring，只需将您的数据源注入您的 JdbcTemplate bean，然后将 JdbcTemplate 注入您的 DAO class，而不是在飞.

Answer 2

感谢您的帮助....最后一个无用的未关闭连接是由错误的日志系统引起的，如下 jboss 日志让它猜测...

2017-05-11 18:12:00,024 INFO  [eu.systemed.commands.workflow.CloseCancelledDocumentCommand] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) before execution of the query:SELECT * FROM systemedpdfdb.documents WHERE state=-3 and closing_date is null
2017-05-11 18:12:00,039 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [DataSource] getConnection()
2017-05-11 18:12:00,273 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [Connection] prepareStatement(SELECT * FROM systemedpdfdb.documents WHERE state=-3 and closing_date is null)
2017-05-11 18:12:00,289 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [PreparedStatement] executeQuery()
2017-05-11 18:12:00,305 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [ResultSet] next()
2017-05-11 18:12:00,305 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [ResultSet] close()
2017-05-11 18:12:00,305 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [PreparedStatement] isClosed()
2017-05-11 18:12:00,320 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [PreparedStatement] close()
2017-05-11 18:12:00,320 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [Connection] isClosed()
2017-05-11 18:12:00,320 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [Connection] close()
2017-05-11 18:12:00,320 INFO  [eu.systemed.commands.workflow.CloseCancelledDocumentCommand] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) after execution of the query:SELECT * FROM systemedpdfdb.documents WHERE state=-3 and closing_date is null
2017-05-11 18:12:00,320 INFO  [eu.systemed.commands.workflow.CloseCancelledDocumentCommand] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) empty result for the query:SELECT * FROM systemedpdfdb.documents WHERE state=-3 and closing_date is null
2017-05-11 18:12:00,320 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [DataSource] getConnection()
2017-05-11 18:12:00,320 DEBUG [jboss.jdbc.spy] (org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-1) java:jboss/datasources/SystemedPdfdataSource4jobs [Connection] getMetaData()

Spring JDBC 模板：queryforlist 不关闭数据库连接？

Spring JDBC template : queryforlist doesn't close the db connection?

java

spring

jdbc

jboss

wildfly-10