feat: 初始化SQLite连接.

src/main/java/com/serliunx/ddns/constant/SystemConstants.java

@@ -82,4 +82,9 @@ public final class SystemConstants {
      * 用户目录下的.yml配置文件
      */
     public static final String USER_SETTINGS_YAML_PATH = USER_DIR + File.separator + CONFIG_YAML_FILE;
+
+    /**
+     * 程序数据库
+     */
+    public static final String SQLITE_URL = "jdbc:sqlite:data.db";
 }

src/main/java/com/serliunx/ddns/core/factory/DatabaseInstanceFactory.java

@@ -1,6 +1,8 @@
 package com.serliunx.ddns.core.factory;
 
 import com.serliunx.ddns.core.instance.Instance;
+import com.serliunx.ddns.support.Assert;
+import com.serliunx.ddns.support.sqlite.SQLiteConnector;
 
 import java.util.Collections;
 import java.util.Set;
@@ -12,10 +14,23 @@ import java.util.Set;
  * @version 1.0.3
  * @since 2024/11/20
  */
-public final class DatabaseInstanceFactory extends AbstractInstanceFactory {
+public final class DatabaseInstanceFactory extends AbstractInstanceFactory implements PersistentInstanceFactory {
+
+    private final SQLiteConnector connector;
+
+    public DatabaseInstanceFactory(SQLiteConnector connector) {
+        this.connector = connector;
+    }
 
     @Override
     protected Set<Instance> load() {
+        Assert.notNull(connector, "数据库连接不能为空!");
+        connector.refresh();
         return Collections.emptySet();
     }
+
+    @Override
+    public boolean save(Instance instance) {
+        return false;
+    }
 }

src/main/java/com/serliunx/ddns/core/factory/PersistentInstanceFactory.java

@@ -0,0 +1,21 @@
+package com.serliunx.ddns.core.factory;
+
+import com.serliunx.ddns.core.instance.Instance;
+
+/**
+ * 可持久化的实例工厂, 支持编辑、保存实例数据.
+ *
+ * @author <a href="mailto:serliunx@yeah.net">SerLiunx</a>
+ * @version 1.0.3
+ * @since 2024/11/20
+ */
+public interface PersistentInstanceFactory extends InstanceFactory {
+
+    /**
+     * 保存实例信息
+     *
+     * @param instance 实例
+     * @return 成功保存返回真, 否则返回假.
+     */
+    boolean save(Instance instance);
+}

src/main/java/com/serliunx/ddns/support/sqlite/SQLiteConnector.java

@@ -0,0 +1,76 @@
+package com.serliunx.ddns.support.sqlite;
+
+import com.serliunx.ddns.constant.SystemConstants;
+import com.serliunx.ddns.core.Refreshable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * SQLite 数据库连接
+ *
+ * @author <a href="mailto:serliunx@yeah.net">SerLiunx</a>
+ * @version 1.0.3
+ * @since 2024/11/20
+ */
+public final class SQLiteConnector implements Refreshable {
+
+    private volatile Connection connection;
+
+    private final Lock initLock = new ReentrantLock();
+
+    private volatile boolean initialized = false;
+
+    private static final Logger log = LoggerFactory.getLogger(SQLiteConnector.class);
+    private static final SQLiteConnector INSTANCE = new SQLiteConnector();
+
+    // private-ctor
+    private SQLiteConnector() {}
+
+    @Override
+    public void refresh() {
+        init();
+    }
+
+    /**
+     * 连接初始化
+     */
+    private void init() {
+        if (initialized) {
+            log.warn("sql connection already initialized");
+            return;
+        }
+
+        if (!initLock.tryLock()) {
+            log.error("sql connection already initialing");
+        }
+
+        try {
+            log.info("initialing sqlite connection.");
+            connection = DriverManager.getConnection(SystemConstants.SQLITE_URL);
+
+            initialized = true;
+            log.info("sqlite connection successfully initialized.");
+        } catch (Exception e) {
+            initialized = false;
+            log.error("sql connection initialization exception: ", e);
+        } finally {
+            initLock.unlock();
+        }
+    }
+
+    /**
+     * 是否已经初始化
+     */
+    public boolean isInitialized() {
+        return initialized;
+    }
+
+    public static SQLiteConnector getInstance() {
+        return INSTANCE;
+    }
+}