【发布时间】:2014-08-23 02:55:02
【问题描述】:
下面的类创建到我的 MYSQL 用户的连接,然后将一些数据提交到表中。我检查并再次检查了用户名和密码,它绝对 100% 正确,但为什么它一直抛出这个内存泄漏?我自己搞不清楚,我一直在阅读所有相关主题,但似乎没有一个问题与我的问题相同。
package com.rs.MYSQL;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import com.rs.Settings;
import com.rs.utils.Lottery;
public class LotteryMYSQL {
private static Connection connection;
private static long lastConnection = System.currentTimeMillis();
public static void createConnection() {
try {
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection(
"jdbc:mysql://runerebellion.com:3306/database",
"user", "pass");//fake user&pass
} catch (Exception e) {
e.printStackTrace();
}
}
public static void destroyConnection() {
try {
connection.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void init() {
createConnection();
}
public static boolean updateInfo() {
try {
if (Settings.DisableMYSQL == true)
return false;
createConnection();
Statement stmt = connection.createStatement();
if (Lottery.getCurrentLotteryWinner() != null)
stmt.executeUpdate("UPDATE info SET moneyEarned = '"
+ Lottery.options.size() + "', lastWinner = '"
+ Lottery.getCurrentLotteryWinner() + "'");
else
stmt.executeUpdate("UPDATE info SET moneyEarned = '"
+ Lottery.options.size() + "', lastWinner = '"
+ Lottery.getLastLotteryWinner() + "'");
destroyConnection();
} catch (Throwable e) {
if (System.currentTimeMillis() - lastConnection > 10000) {
destroyConnection();
createConnection();
lastConnection = System.currentTimeMillis();
}
}
return false;
}
}
下面是内存泄漏
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1137)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:356)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2504)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2541)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2323)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:832)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:417)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.rs.MYSQL.LotteryMYSQL.createConnection(LotteryMYSQL.java:19)
at com.rs.Launcher.main(Launcher.java:103)
Caused by: java.net.ConnectException: Connection timed out: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:258)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:306)
... 16 more
【问题讨论】:
-
您是否可以通过命令行或 MySQL Workbench 等客户端连接到 MySQL 数据库?
-
是的,我刚刚用软件测试了一下,heidsql @isim
-
@RuneTebellion 这家伙给出了一个相当彻底的解决方案,有很多东西可以尝试here。试一试。