我的 Java SQLite 驱动程序 (JDBC) 有问题。当我想加载数据库时,它说它已加载,但实际上它已关闭。我将代码放在不同的文件中:
SQLite.java
package net.jeddsan;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.SQLException;
public class SQLite {
public static Connection createOrOpenDatabase(String database) {
String url = "jdbc:sqlite:" + database;
try (Connection conn = DriverManager.getConnection(url)) {
if (conn != null) {
System.out.println("A new database has been created.");
conn.setAutoCommit(false);
return conn;
}else{
return null;
}
} catch (SQLException e) {
System.out.println(e.getMessage());
return null;
}
}
}
MainController.java
@Override
public void initialize(URL url, ResourceBundle rb) {
c = SQLite.createOrOpenDatabase("test.db");
try {
sta = c.createStatement();
sta.executeQuery("INSERT INTO token (token) VALUES ('123')");
sta.close();
} catch (SQLException ex) {
Logger.getLogger(MainController.class.getName()).log(Level.SEVERE, null, ex);
}
try {
c.close();
} catch (SQLException ex) {
Logger.getLogger(MainController.class.getName()).log(Level.SEVERE, null, ex);
}
}
日志
SCHWERWIEGEND: null
java.sql.SQLException: database connection closed
at org.sqlite.core.CoreConnection.checkOpen(CoreConnection.java:336)
at org.sqlite.jdbc4.JDBC4Connection.createStatement(JDBC4Connection.java:38)
at org.sqlite.jdbc3.JDBC3Connection.createStatement(JDBC3Connection.java:193)
at net.jeddsan.MainController.initialize(MainController.java:103)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at net.jeddsan.koradesktop.start(koradesktop.java:22)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)
最佳答案
当您离开其作用域时,此 try-with-resources
构造将调用 Connection 上的 close
方法:
try (Connection conn = DriverManager.getConnection(url)) {
return conn;
}
因此,您实际上返回了关闭的连接。
将其更改为常规的 try
构造以返回实时连接:
try {
Connection conn = DriverManager.getConnection(url);
return conn;
} catch (SQLException e) {
return null;
}
关于java.sql.SQLException : database connection closed,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42494178/