java.net.SocketException : java.net.SocketException: 打开的文件太多

Question

我有一个大型 Java 应用程序(用于生成某种类型的报告)，其中下面的类用于创建数据源。

 import org.apache.log4j.Logger;
 import org.springframework.jdbc.datasource.DriverManagerDataSource;
 import com.mysql.jdbc.Connection;
 public class DatabaseConnection
  {
     private static final Logger LOGGER = Logger.getLogger(DatabaseConnection.class.getName());
    @SuppressWarnings("deprecation")
    public static DriverManagerDataSource jdbcConnection(WebmartConfiguration webmartconnection)
    {
        DriverManagerDataSource dataSource = null;
        try
        {
            dataSource = new DriverManagerDataSource("com.mysql.jdbc.Driver", "jdbc:mysql://" + webmartconnection.getHostname() + ":" + webmartconnection.getPort() + "/" + webmartconnection.getDatabasename() + "", webmartconnection.getUsername(), webmartconnection.getPassword());
    }
    catch (Exception sqle)
    {
        LOGGER.info(sqle);
    }
    return dataSource;
 }
}

并且该数据源被传递给许多方法，这些方法用于使用 JDBCTEMPLATE 的查询方法执行查询。一段时间后，应用程序运行平稳并生成报告，但一段时间后应用程序终止并出现以下堆栈跟踪。

ERROR [run has started] (DivisionThread.java:217) - Could not get JDBC Connection;      nested exception is com.mysql.jdbc.CommunicationsException:     Communications link failure due to underlying exception:    

** BEGIN NESTED EXCEPTION **    

java.net.SocketException    
MESSAGE: java.net.SocketException: Too many open files  

STACKTRACE: 

java.net.SocketException: java.net.SocketException: Too many open files 
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:156)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2641)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
   at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
   at java.sql.DriverManager.getConnection(DriverManager.java:579)
   at java.sql.DriverManager.getConnection(DriverManager.java:190)
   at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriverManager(DriverManagerDataSource.java:173)
at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriver(DriverManagerDataSource.java:164)
at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnectionFromDriver(AbstractDriverBasedDataSource.java:149)
at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnection(AbstractDriverBasedDataSource.java:119)
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:573)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:637)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:666)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:674)
at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:729)
at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:745)
at com.mpsinsight.reporting.dao.common.CommonUtilReport.getOutFileName(CommonUtilReport.java:1509)
at com.mpsinsight.reporting.bean.common.ActionEnum$9.getparameterType(ActionEnum.java:507)
at com.mpsinsight.reporting.main.common.JasperReport.populateParameters(JasperReport.java:142)
at com.mpsinsight.reporting.main.common.JasperReport.generateReport(JasperReport.java:61)
at com.mpsinsight.reporting.main.common.GenerateReport$4.generateReport(GenerateReport.java:123)
at com.mpsinsight.reporting.main.common.DivisionThread.run(DivisionThread.java:179)


** END NESTED EXCEPTION **  

例子:以下是使用数据源的应用程序方法之一。

public String getOutFileName(DriverManagerDataSource datasource, WebmartConfiguration     webmartconnection, String abbrev)
    {
    DriverManagerDataSource dmDatasource = null;
    dmDatasource = datasource;
    if (dmDatasource == null)
    {
        dmDatasource = DatabaseConnection.jdbcConnection(webmartconnection);
    }
    JdbcTemplate jdbcTemplateOb = new JdbcTemplate(dmDatasource);
    String sql = QueryList.Value("outFileNameQuery");

    LOGGER.info("abbrev :::: " + abbrev);
    LOGGER.info("outFileNameQuery :::: " + sql);

    String pathname = (String) jdbcTemplateOb.queryForObject(sql, new Object[] { abbrev }, String.class);

    LOGGER.info("pathname :::: " + pathname);
    return pathname;
}

谁能解释一下 too many open files 错误的原因以及我该如何解决。

编辑:我在 linux 环境下工作。以上错误仅在linux环境下出现。

Answer 1

使用以下 linux 命令检查打开文件限制。

ulimit -a 

并且您可以通过 root 用户在以下文件中提供打开文件限制。

/etc/security/limits.conf 

例如

{username}       soft       nofile   1024
{username}       hard   nofile        65536