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如何强制超时为DriverManager.getConnection（）方法调用？

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我有一个应用程序，它将与MySQL Build 数据库连接并执行查询 . 有时 DriverManager.getConnection() 方法调用需要2秒，有时需要30秒 . 有没有办法在2秒后控制此方法超时？

DriverManager.setLoginTimeout() 似乎不起作用 .

实际上，我可以通过将线程休眠为超时值并在唤醒后关闭连接来设置 statement.executeQuery() 的超时 . 但它的连接 Build 部分我无法真正设置超时 .

非常感谢任何帮助 .

java timeout database-connection

6 回答

  • 4

    如果没有其他选项，您可以始终只在一个单独的线程中执行调用，如果它在2秒内没有完成，您将中止/忽略该线程 .

    EDIT 这是我的想法的一个例子：

    public class Dummy extends Thread {
private volatile Connection conn = null;
@Override
public void run() {
    try {
        this.conn = DriverManager.getConnection("foobar") ;
    } catch (SQLException e) {
        e.printStackTrace();
    }
}
static public Connection getConnection() {
    Dummy d = new Dummy() ;
    d.start() ;
    try {
        Thread.sleep(2000) ;
    } catch (InterruptedException e) {}
    return d.conn ;
}
}

    然后，您可以在代码中的其他位置调用静态Dummy.getConnection（）方法 . 一个缺点是这种方法总是花费2秒，但是当线程完成时将其更改为立即返回并不太难 .

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  • 0

    您可以使用Java中的 ExecutorService 接口 . 以下是您需要做的样本 .

    Future<Boolean> future = executor.submit(YOUR_METHOD);
future.get(TIMEOUT_YOU_NEED, TimeUnit.SECONDS);
    回复于
  • 0

    尝试在连接URL或连接池上设置socketTimeout（以毫秒为单位的时间）（如果使用池） . 注意不要将此值设置得太低，否则会覆盖语句超时值 .

    try {
    this.conn = DriverManager.getConnection("url?socketTimeout=2000") ;
} catch (SQLException e) {
    e.printStackTrace();
}

    要么

    <jdbc-connection-pool 
                     connection-validation-method="table"
                     fail-all-connections="true"
                     idle-timeout-in-seconds="300"
                     is-connection-validation-required="true"
                     statement-timeout-in-seconds="2"
                     validation-table-name="dual"
                     ..... >
   <property name="databaseName" value="...."/>
   <property name="serverName" value="....."/>
   <property name="User" value="....."/>
   <property name="Password" value="......."/>
   <property name="URL" value="jdbc:mysql://...../...."/>
   <property name="driverClass" value="...."/>
   <property name="socketTimeout" value="2000"/>
</jdbc-connection-pool>

    设置此项修复了我的超时问题 .

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  • 2
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  • 0

    感谢codebolt，我不知道它是否是最好的解决方案，但这对我有用 . 10秒超时 .

    public class Dummy extends Thread {
             private volatile java.sql.Connection conn = null;
             private boolean sleep = true;
            @Override
             public void run() {
                 try {

                     String driver = "net.sourceforge.jtds.jdbc.Driver";
                     Class.forName(driver).newInstance();                       
                     //timeout
                     DriverManager.setLoginTimeout(10);
                     this.conn = DriverManager.getConnection(url, user, pwd);
                     sleep = false;
                 } catch (Exception e) {}
             }
             public java.sql.Connection getConnection() {
                 Dummy d = new Dummy() ;
                 d.start() ;
                 try {
                     for(int i=1; i<=10; i++) {
                         //Wait 1 second
                         if (d.sleep){
                             Thread.sleep(1000);  
                         }
                     }  
                 } catch (InterruptedException e) {}
                 return d.conn ;
             }
             }

    电话：

    Dummy a = new Dummy();
connection = a.getConnection();
if (connection != null) {....
    回复于
  • 1

    我扩展了CodeBolt和anpadia的答案，以完成以下完整课程 . 它只有一个静态方法接受所有需要的连接参数，包括超时持续时间 . 此外，如果它们发生，该方法也会抛出SQLException和ClassNotFoundException .

    用法：

    String connectionUrl = "...";
String user = "...";
String password = "...";
String driver = "org.postgresql.Driver"; // for example

int timeoutInSeconds = 5;

Connection myConnection =
    ConnectWithTimeout.getConnection(connectionUrl, user, password, driver, timeoutInSeconds);

    以下是实施：

    import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.SQLException;


public class ConnectWithTimeout extends Thread {

    private static String _url;
    private static String _user;
    private static String _password;
    private static String _driver;

    private static volatile Connection _connection = null;
    private static volatile boolean _sleep = true;
    private static volatile SQLException _sqlException = null;
    private static volatile ClassNotFoundException _classNotFoundException = null;

    @Override
    public void run() {
        try {
            Class.forName(_driver);
            _connection = DriverManager.getConnection(_url, _user, _password);
        }
        catch (SQLException ex) {
            _sqlException = ex;
        }
        catch (ClassNotFoundException ex) {
            _classNotFoundException = ex;
        }
        _sleep = false;
    }

    public static Connection getConnection(String url, 
                                           String user, 
                                           String password, 
                                           String driver, 
                                           int timeoutInSeconds) 
        throws SQLException, ClassNotFoundException {

        checkStringOrThrow(url,      "url");
        checkStringOrThrow(user,     "user");
        checkStringOrThrow(password, "password");
        checkStringOrThrow(driver,   "driver");

        if (timeoutInSeconds < 1) {
            throw new IllegalArgumentException(
                "timeoutInSeconds must be positive");
        }

        _url = url;
        _user = user;
        _password = password;
        _driver = driver;

        ConnectWithTimeout conn = new ConnectWithTimeout();
        conn.start();

        try {
            for (int i = 0; i < timeoutInSeconds; i++) {
                if (_sleep) {
                    Thread.sleep(1000);
                }
            }
        }
        catch (InterruptedException ex) {
        }

        if (_sqlException != null) {
            throw _sqlException;
        }

        if (_classNotFoundException != null) {
            throw _classNotFoundException;
        }

        return _connection;
    }

    private static void checkStringOrThrow(String variable, String variableName) {
        if (variable == null || variable.length() == 0) {
            throw new IllegalArgumentException(
                "String is null or empty: " + variableName);
        }
    }
}
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