diff --git a/DBHelper.java b/DBHelper.java
new file mode 100644
index 0000000..1c9fef1
--- /dev/null
+++ b/DBHelper.java
@@ -0,0 +1,111 @@
+package com.example.sparrownotes.util;
+
+import android.content.Context;
+import android.database.sqlite.SQLiteDatabase;
+import android.util.ArrayMap;
+
+import com.example.sparrownotes.bean.NoteBean;
+import com.example.sparrownotes.bean.UserBean;
+import com.example.sparrownotes.util.Constant;
+import com.j256.ormlite.android.apptools.OrmLiteSqliteOpenHelper;
+import com.j256.ormlite.dao.Dao;
+import com.j256.ormlite.support.ConnectionSource;
+import com.j256.ormlite.table.TableUtils;
+
+import java.sql.SQLException;
+
+/**
+ * 数据库帮助类
+ *
+ * @author Horsen
+ */
+@SuppressWarnings("AlibabaRemoveCommentedCode")
+public class DBHelper extends OrmLiteSqliteOpenHelper {
+    /**
+     * 防止多线程同时操作, 实现单例模式, 并锁定线程
+     * 数组存储App中所有的Dao对象的Map集合
+     */
+    private static DBHelper dbHelper = null;
+    private ArrayMap<String, Dao> daos = new ArrayMap<>();
+
+    public static synchronized DBHelper getInstance(Context context) {
+        if (dbHelper == null) {
+            synchronized (DBHelper.class) {
+                if (dbHelper == null) {
+                    dbHelper = new DBHelper(context);
+                }
+            }
+        }
+        return dbHelper;
+    }
+
+    private DBHelper(Context context) {
+        super(context, Constant.DB_NAME, null, Constant.DB_VERSION);
+    }
+
+    /**
+     * 包含创建表的语句
+     *
+     * @param sqLiteDatabase
+     * @param connectionSource
+     */
+    @Override
+    public void onCreate(SQLiteDatabase sqLiteDatabase, ConnectionSource connectionSource) {
+        try {
+            TableUtils.createTable(connectionSource, UserBean.class);
+            TableUtils.createTable(connectionSource, NoteBean.class);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    /**
+     * 包含新建表的语句
+     * 就是删了再创罢了
+     *
+     * @param sqLiteDatabase
+     * @param connectionSource
+     * @param i
+     * @param i1
+     */
+    @Override
+    public void onUpgrade(SQLiteDatabase sqLiteDatabase, ConnectionSource connectionSource, int i, int i1) {
+        try {
+            TableUtils.dropTable(connectionSource, UserBean.class, false);
+            TableUtils.dropTable(connectionSource, NoteBean.class, false);
+            onCreate(sqLiteDatabase, connectionSource);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * 根据传入的Dao路径获取这个Dao的单例对象, 要么从daos中获取, 要么新建一个存入daos
+     */
+    @Override
+    public synchronized Dao getDao(Class clazz) throws SQLException {
+        Dao dao = null;
+        String className = clazz.getSimpleName();
+        if (daos.containsKey(className)) {
+            dao = daos.get(className);
+        }
+        if (dao == null) {
+            dao = super.getDao(clazz);
+            daos.put(className, dao);
+        }
+        return dao;
+    }
+
+    /**
+     * 释放资源
+     */
+    @Override
+    public void close() {
+        super.close();
+        for (String key : daos.keySet()) {
+            Dao dao = daos.get(key);
+            dao = null;
+        }
+    }
+}