我有一个 Java Servlet，我想将连接池与 jdbc(数据库:mysql)一起使用。

所以这就是我正在做的:

(这个类是public final class DBConnector)

private static final HikariDataSource dataSource = new HikariDataSource();
private static final HikariDataSource dataSource2 = new HikariDataSource();
private static final HikariDataSource dataSource3 = new HikariDataSource();

static {
    dataSource.setDriverClassName("com.mysql.jdbc.Driver");
    dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/contentdb");
    dataSource.setUsername("root2");
    dataSource.setPassword("password");
    dataSource.setMaximumPoolSize(400);
    dataSource.setMinimumIdle(5);
    dataSource.setLeakDetectionThreshold(15000);
    dataSource.setConnectionTestQuery("SELECT 1");
    dataSource.setConnectionTimeout(1000);

    dataSource2.setDriverClassName("com.mysql.jdbc.Driver");
    dataSource2.setJdbcUrl("jdbc:mysql://localhost:3306/userdb");
    dataSource2.setUsername("root");
    dataSource2.setPassword("password");
    dataSource2.setMaximumPoolSize(300);
    dataSource2.setMinimumIdle(5);
    dataSource2.setLeakDetectionThreshold(15000);
    dataSource2.setConnectionTestQuery("SELECT 1");
    dataSource2.setConnectionTimeout(1000);

    dataSource3.setDriverClassName("com.mysql.jdbc.Driver");
    dataSource3.setJdbcUrl("jdbc:mysql://localhost:3306/analysedb");
    dataSource3.setUsername("root2");
    dataSource3.setPassword("password");
    dataSource3.setMaximumPoolSize(200);
    dataSource3.setMinimumIdle(5);
    dataSource3.setLeakDetectionThreshold(15000);
    dataSource3.setConnectionTestQuery("SELECT 1");
    dataSource3.setConnectionTimeout(1000);

}

private DBConnector() {
    //
}

public static Connection getConnection(int dataBase) throws SQLException {
    if (dataBase == 0) {
        return dataSource.getConnection();
    } else if (dataBase == 1) {
        return dataSource2.getConnection();
    } else {
        return dataSource3.getConnection();
    }
}

当我想调用它时:

Connection con = null;
    PreparedStatement query = null;
    ResultSet result = null;
    try {
        con = DBConnector.getConnection(0);
    }catch(SQLException ex){
    }finally{
       if (result != null) {
            try {
                result.close();
            } catch (SQLException logOrIgnore) {
            }
        }
        if (query != null) {
            try {
                query.close();
            } catch (SQLException logOrIgnore) {
            }
        }
        if (con != null) {
            try {
                con.close();
            } catch (SQLException logOrIgnore) {
            }
        }
    }

但是当我点击我的应用程序时，过了一会儿它开始挂起并且我收到以下错误:

java.sql.SQLException: Timeout after 1001ms of waiting for a connection.
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:208)
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:108)
at main.java.db.DBConnector.getConnection(DBConnector.java:60)
at main.java.ressources.SingleItemData.getVotes(SingleItemData.java:1088)
at main.java.item.methods.GET.content.GetStreamContent.getStreamContent(GetStreamContent.java:126)
at main.java.RestService.doGet(RestService.java:254)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)

Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: 通信链接失败

我将 mysql max_conncethions 设置为 1000。“SHOW PROCESSLIST”查询显示了很多 hibernate 进程。这些是闲置的吗？

我真的有点被困在这里了。不知道是哪个设置导致了这个问题。所以我的问题是 - 是什么导致了这个错误？我究竟做错了什么？任何帮助表示赞赏。

编辑: 设置 Mysql(本地主机):

[mysqld]

user=mysql

port=3306

socket      =/Applications/XAMPP/xamppfiles/var/mysql/mysql.sock

key_buffer=16M

max_allowed_packet=1M

table_open_cache=64

sort_buffer_size=512K

net_buffer_length=8K

read_buffer_size=256K

read_rnd_buffer_size=512K

myisam_sort_buffer_size=8M

max_connections = 1000

wait_timeout = 28800

interactive_timeout = 28800

HikariCP:HikariCP-java6-2.2.5.jar

MySQL 连接器:mysql-connector-java-5.1.25-bin.jar

最佳答案

几件事。首先，什么版本的 HikariCP、Java 和 MySQL 驱动程序？

其次，一个池中有 400 个连接？ Way too many!从每个池中的 10 到 20 个开始。您会惊讶于您每秒可以处理几千个事务。

三、这是第二题in the FAQ .阅读答案和链接。您需要将 maxLifetime 设置为比您的 MySQL native 超时更短(1 分钟)的值。

最后，打开 DEBUG 日志记录，HikariCP 没有噪音。每 30 秒，内务处理线程运行一次并记录池统计信息。

关于java - HikariCP 连接过多，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27505536/