私はこれを理解するのに少し苦労しています。これが何が起こっているかです。OracleデータベースへのJDBC接続を保持する新しいスレッドを生成しています。データベースに接続するように要求すると、start（）メソッドが呼び出されている間、親スレッドは実行を続けますが、子に（別のメソッドで）クエリを実行するように要求すると、親スレッドは子スレッドの待機中にスタックします。その仕事を終える方法。これを修正する方法として何か推測はありますか？前もって感謝します！
public class Main extends Thread{
public Main()
{
}
public void myCounter() {
int i = 0;
DBConnection myConnection = null;
for(;;)
{
i++;
System.out.println("time: " + i);
if( i == 5)
{
myConnection = new DBConnection("localhost", 1521, "hr", "hr", "XE");
myConnection.start();
}
if(i == 10)
try {
myConnection.runQuery("Select * from hr.numbers order by dbms_random.value");
} catch (SQLException e) {
e.printStackTrace();
}
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public void run()
{
myCounter();
}
public static void main(String[] args) {
Main boot = new Main();
boot.start();
}
}
public class DBConnection extends Thread{
Connection myConnection;
int port;
String user;
String password;
String serviceName;
String host;
public void run()
{
setUpConnection(host, port, user, password, serviceName);
}
/**
* Sets up variables to create a connection to Oracle.
*
* @param host host
* @param port port
* @param user user
* @param password password
*/
public DBConnection(String host, int port, String user, String password, String serviceName)
{
this.host = host;
this.port = port;
this.user = user;
this.password = password;
this.serviceName = serviceName;
}
private void setUpConnection(String host, int port, String user,
String password, String dataBase) {
System.out.println("-------- Oracle "
+ "JDBC Connection Testing ------------");
try {
Class.forName("oracle.jdbc.OracleDriver");
} catch (ClassNotFoundException e) {
System.out.println("Couldn't find Oracle JDBC Driver... :-(");
e.printStackTrace();
return;
}
System.out.println("Oracle JDBC Driver Registered!");
myConnection = null;
try {
myConnection = DriverManager.getConnection(
"jdbc:oracle:thin:@//"
+ host
+ ":"
+ port
+ "/"
+ dataBase,
user, password
);
} catch (SQLException e) {
System.out.println("Connection Failed!");
e.printStackTrace();
return;
}
if (myConnection != null) {
System.out.println("Connected to Oracle! :-)");
} else {
System.out.println("Failed to make connection!");
}
}
/**
* Queries the database and returns a ResultSet
* @param query SQL
* @throws SQLException
*/
public ResultSet runQuery(String query) throws SQLException
{
System.out.println(" [DBConnection] Started Running @ " + (new SimpleDateFormat("HH:mm:ss:S")).format(new Date()));
ResultSet rs = null;
Statement stt = myConnection.createStatement();
rs = stt.executeQuery(query);
System.out.println(" [DBConnection] Finished Running @: " + (new SimpleDateFormat("HH:mm:ss:S")).format(new Date()));
return rs;
}
これが私が得る出力です：
time: 1
time: 2
time: 3
time: 4
time: 5
-------- Oracle JDBC Connection Testing ------------
Oracle JDBC Driver Registered!
time: 6
Connected to Oracle! :-)
time: 7
time: 8
time: 9
time: 10
[DBConnection] Started Running @ 14:46:00:660
[DBConnection] Finished Running @: 14:46:12:750
time: 11
time: 12
time: 13
time: 14
........。