Java SpringJDBC模板：queryforlist不'；t关闭数据库连接？

在wildfly web应用程序中有后台作业，其中

NamedParameterJdbcTemplate

用于检索记录列表，我有一个数据库连接泄漏，阻止作业在一段时间后工作，

无法获取JDBCConnectionException

在监视了部分sql请求之后，我发现了以下内容。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);

}

这正常吗？还是我误用了SpringJDBC模板

提前谢谢

---

David L.

实际的数据库连接由数据源实现包装。您使用的是什么数据源实现

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

---

另外，如果您使用的是Spring，只需将数据源注入JDBCTemplatebean，然后将JdbcTemplate注入DAO类，而不是动态创建一个新的NamedParameterJdbcTemplate实例。

谢谢您的帮助。。。。最后一个无用的未关闭连接是由错误的日志记录系统造成的，因为下面的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() 

---

在

queryForList

调用之后添加一些日志记录，这样我们就可以确定额外的

getConnection

是从那里创建的。

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()