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经常用得到的安卓数据库基类

發布時間：2023/11/27 生活经验 41 豆豆

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//創建數據庫??
public?class?DBCreate?{??
????public?static?void?CreateDatabase(SQLiteDatabase?db)?{??
????????db.beginTransaction();??
????????try?{??
????????????create_NetTaskBuffer(db);??
??
????????????insert_SQL(db);??
??
????????????db.setTransactionSuccessful();??
????????}?catch?(Exception?e)?{??
????????????e.printStackTrace();??
????????}?finally?{??
????????????db.endTransaction();??
????????}??
????}??
??
????//?緩存??
????private?static?void?create_NetTaskBuffer(SQLiteDatabase?db)?{??
????????db.execSQL("DROP?TABLE?IF?EXISTS?NetTaskBuffer");??
????????StringBuilder?sql?=?new?StringBuilder();??
????????sql.append("CREATE?TABLE?IF?NOT?EXISTS?NetTaskBuffer?(");??
????????sql.append("?id?INTEGER?PRIMARY?KEY?AUTOINCREMENT,");?//?這一列不能修改??
????????sql.append("?label?TEXT?COLLATE?NOCASE,");?//??
????????sql.append("?param?TEXT?COLLATE?NOCASE,");?//??
????????sql.append("?result?TEXT?COLLATE?NOCASE,");?//??
????????sql.append("?remark?TEXT?COLLATE?NOCASE,");??
????????sql.append("?time?LONG)");?//??
????????db.execSQL(sql.toString());??
????}??
??
????//?插入語句,初始化數據庫使用??
????private?static?void?insert_SQL(SQLiteDatabase?db)?{??
??????????
????}??
}??
??
??
??
//----------------------數據庫操作基類--------------------------------------//??
??
??
/**?
?*?數據庫基本操作類,數據庫的創建,更新的操作都在這里進行?
?*??
?*?@author?yizhe?
?*?@date?2014-9-11?
?*/??
public?abstract?class?DBHelper?extends?SQLiteOpenHelper?{??
??
????static?String?name?=?"hk.db";?//?數據庫名稱??
????static?CursorFactory?cursorFactory?=?null;??
????static?int?version?=?1000;//?初始版本:1000??
????Context?context;??
??
????protected?ContentValues?contentValues;?//?cursor對象轉行中介,給子類使用??
??
????protected?String?tableName;??
??
????protected?DBHelper(Context?context,?String?tableName)?{??
????????super(context,?name,?cursorFactory,?version);??
????????this.context?=?context;??
????????this.tableName?=?tableName;??
????}??
??
????/**?
?????*?軟件第一次安裝的時候會調用,覆蓋安裝不會調用?
?????*/??
????public?void?onCreate(SQLiteDatabase?db)?{??
????????//?所有表的創建過程都在這里進行??
????????DBCreate.createDatabase(db);??
????}??
??
????/**?
?????*?覆蓋安裝,當版本號version發生變化的時候,這個方法才會被調用,而且只執行一次?
?????*/??
????public?void?onUpgrade(SQLiteDatabase?db,?int?oldVersion,?int?newVersion)?{??
????????onCreate(db);??
????????//?if?(oldVersion?<?109)?{??
????????//?onCreate(db);??
????????//?}?else?{??
????????//?}??
????}??
??
????/**?
?????*?每次成功打開數據庫后首先被執行?
?????*/??
????public?void?onOpen(SQLiteDatabase?db)?{??
????????super.onOpen(db);?//?每次成功打開數據庫后首先被執行??
????}??
??
????public?void?finalize()?{??
????????close();??
????}??
??
????//?--------------------------sql方法---------------------------------//??
????/**?
?????*?執行sql,沒有返回?
?????*/??
????public?void?execSQL(String?sql)?{??
????????System.out.println("==execSQL=="?+?sql);??
????????SQLiteDatabase?db?=?getWritableDatabase();??
????????db.execSQL(sql);??
????????db.close();??
????}??
??
????/**?
?????*?批量執行sql,內部啟用事務?
?????*??
?????*?@param?list?
?????*????????????sql列表?
?????*?@return?是否執行成功?
?????*/??
????public?boolean?execSQLBatch(ArrayList<String>?list)?{??
????????SQLiteDatabase?db?=?getWritableDatabase();??
????????db.beginTransaction();??
????????try?{??
????????????for?(String?sql?:?list)?{??
????????????????db.execSQL(sql);??
????????????}??
????????????db.setTransactionSuccessful();??
????????}?catch?(Exception?e)?{??
????????????e.printStackTrace();??
????????????return?false;??
????????}?finally?{??
????????????db.endTransaction();??
????????????db.close();??
????????}??
????????return?true;??
????}??
??
????/**?
?????*?根據id刪除記錄?
?????*??
?????*?@param?id?
?????*????????????表中必須有"id"字段?
?????*?@return?the?number?of?rows?affected?if?a?whereClause?is?passed?in,?0?
?????*?????????otherwise.?To?remove?all?rows?and?get?a?count?pass?"1"?as?the?
?????*?????????whereClause.?
?????*/??
????public?int?delete(int?id)?{??
????????SQLiteDatabase?db?=?getWritableDatabase();??
????????int?result?=?db.delete(tableName,?"id=?",?new?String[]?{?id?+?""?});??
????????db.close();??
????????return?result;??
????}??
??
????/**?
?????*?刪除:?只需要寫where?條件(不帶where)?和?參數?
?????*??
?????*?@param?whereStr?
?????*????????????例如:?"id=?"?
?????*?@param?arr?
?????*????????????例如:?new?String[]?{?"123"?}?
?????*?@return?受影響的行?
?????*/??
????public?int?delete(String?whereStr,?String[]?arr)?{??
????????SQLiteDatabase?db?=?getWritableDatabase();??
????????int?result?=?db.delete(tableName,?whereStr,?arr);??
????????db.close();??
????????return?result;??
????}??
??
????/**?
?????*?清空表?
?????*/??
????public?void?clearTable()?{??
????????SQLiteDatabase?db?=?getWritableDatabase();??
????????db.execSQL("delete?from?"?+?tableName);??
????????db.close();??
????}??
??
????/**?
?????*?通用查詢,多用于事務中?
?????*/??
????public?static?Cursor?Query(SQLiteDatabase?db,?String?sql)?{??
????????System.out.println("==Query=="?+?sql);??
????????return?db.rawQuery(sql,?new?String[]?{});??
????}??
??
????/**?
?????*?通用執行sql,,多用于事務中?
?????*??
?????*/??
????public?static?void?execSQL(SQLiteDatabase?db,?String?sql)?{??
????????System.out.println("==execSQL=="?+?sql);??
????????db.execSQL(sql);??
????}??
??
}??
??
//-------------------------下面是一個具體實現的DEMO-------------------------------//??
/**?
?*?dao類,實現基本的數據庫操作<br/>?
?*?需要保存到數據庫中的對象的屬性不能使用基本類型,建議只使用Integer?和?String<br/>?
?*?做為通用對象,從demo創建只要修改tableName即可?
?*??
?*?@author?yizhe?
?*?@date?2012-5-18?
?*/??
public?class?NetTaskBufferDao?extends?DBHelper?{??
????int?expiryDays?=?10;?//?數據緩存有效期??
??
????public?NetTaskBufferDao(Context?context)?{??
????????super(context,?"NetTaskBuffer");??
????}??
??
????//?pojo的整數都需要使用Long類型?或者Integer類型?建議使用Long??
????public?void?iniContentValues(NetTaskBuffer?pojo)?{??
????????contentValues?=?new?ContentValues();??
????????contentValues.put("id",?pojo.id);??
????????contentValues.put("label",?pojo.label);??
????????contentValues.put("param",?pojo.param);??
????????contentValues.put("result",?pojo.result);??
????????contentValues.put("remark",?pojo.remark);??
????????contentValues.put("time",?pojo.time);??
????}??
??
????public?NetTaskBuffer?setBaseItem(Cursor?cursor)?{??
????????NetTaskBuffer?pojo?=?new?NetTaskBuffer();??
????????pojo.id?=?cursor.getInt(cursor.getColumnIndex("id"));??
????????pojo.label?=?cursor.getString(cursor.getColumnIndex("label"));??
????????pojo.param?=?cursor.getString(cursor.getColumnIndex("param"));??
????????pojo.result?=?cursor.getString(cursor.getColumnIndex("result"));??
????????pojo.remark?=?cursor.getString(cursor.getColumnIndex("remark"));??
????????pojo.time?=?cursor.getLong(cursor.getColumnIndex("time"));??
????????return?pojo;??
????}??
??
????//?--------------------自定義方法--------------------------------//??
????public?String?getBuffer(String?label,?String?param)?{??
????????String?sql?=?"select?*?from?"?+?tableName??
????????????????+?"?where?label=??and?param=??";??
????????NetTaskBuffer?obj?=?getOneAsSQL(sql,?new?String[]?{?label,?param?});??
????????if?(null?==?obj)?{??
????????????return?null;??
????????}??
????????Date?time?=?new?Date(obj.time);??
????????Calendar?c?=?Calendar.getInstance();??
??
????????c.add(Calendar.DAY_OF_MONTH,?-expiryDays);??
????????if?(time.compareTo(c.getTime())?<?0)?{??
????????????delete(obj.id);??
????????????return?null;??
????????}??
????????return?obj.result;??
????}??
??
????public?String?getBuffer(String?label,?String?param,?String?remark)?{??
????????String?sql?=?"select?*?from?"?+?tableName??
????????????????+?"?where?label=??and?param=??and?remark=?";??
????????NetTaskBuffer?obj?=?getOneAsSQL(sql,?new?String[]?{?label,?param,??
????????????????remark?});??
????????if?(null?==?obj)?{??
????????????return?null;??
????????}??
????????Date?time?=?new?Date(obj.time);??
????????Calendar?c?=?Calendar.getInstance();??
??
????????c.add(Calendar.DAY_OF_MONTH,?-expiryDays);??
????????if?(time.compareTo(c.getTime())?<?0)?{??
????????????delete(obj.id);??
????????????return?null;??
????????}??
????????return?obj.result;??
????}??
??
????public?void?deleteBuffer(String?label)?{??
????????String?whereSql?=?"?label=?";??
????????delete(whereSql,?new?String[]?{?label?});??
????}??
??
????public?void?deleteBuffer(String?label,?String?param)?{??
????????String?whereSql?=?"?label=??and?param=?";??
????????delete(whereSql,?new?String[]?{?label,?param?});??
????}??
??
????public?void?deleteBuffer(String?label,?String?param,?String?remark)?{??
????????String?whereSql?=?"?label=??and?param=??and?remark=?";??
????????delete(whereSql,?new?String[]?{?label,?param,?remark?});??
????}??
??
????//?--------------------基礎方法---------------------------------//??
??
????/**?
?????*?根據sql獲取list?
?????*/??
????public?ArrayList<NetTaskBuffer>?getListAsSQL(String?sql)?{??
????????SQLiteDatabase?db?=?getReadableDatabase();??
????????Cursor?cursor?=?db.rawQuery(sql,?new?String[]?{});??
????????ArrayList<NetTaskBuffer>?itemList?=?new?ArrayList<NetTaskBuffer>();??
????????for?(cursor.moveToFirst();?!(cursor.isAfterLast());?cursor.moveToNext())?{??
????????????itemList.add(setBaseItem(cursor));??
????????}??
????????cursor.close();??
????????db.close();??
????????return?itemList;??
????}??
??
????/**?
?????*?根據ID獲取一條記錄?
?????*/??
????public?NetTaskBuffer?getById(int?id)?{??
????????String?sql?=?"select?*?from?"?+?tableName?+?"?where?id="?+?id;??
????????return?getOneAsSQL(sql,?null);??
????}??
??
????/**?
?????*?返回結果中的提一條記錄?
?????*/??
????public?NetTaskBuffer?getOneAsSQL(String?sql,?String[]?arr)?{??
????????SQLiteDatabase?db?=?getReadableDatabase();??
????????Cursor?cursor?=?db.rawQuery(sql,?arr);??
????????try?{??
????????????if?(null?!=?cursor?&&?cursor.getCount()?>?0)?{??
????????????????cursor.moveToFirst();??
????????????????return?setBaseItem(cursor);??
????????????}??
????????}?finally?{??
????????????cursor.close();??
????????????db.close();??
????????}??
????????return?null;??
????}??
??
????/**?
?????*?保存對象到數據庫,自動判斷插入還是更像?
?????*??
?????*?@return?返回更新的記錄數,或者?插入數據的id,如果返回值<=0表示失敗?
?????*/??
????public?long?save(NetTaskBuffer?pojo)?{??
????????if?(null?==?pojo.time?||?0?==?pojo.time)?{??
????????????pojo.time?=?new?Date().getTime();??
????????}??
????????Long?idOrEffectRows?=?0l;??
????????if?(null?==?pojo.id?||?pojo.id?<?1)?{??
????????????idOrEffectRows?=?insert(pojo);??
????????}?else?{??
????????????idOrEffectRows?=?(long)?update(pojo);??
????????}??
????????return?idOrEffectRows;??
????}??
??
????/**?
?????*?添加數據,自動插入id?
?????*??
?????*?@return?the?row?ID?of?the?newly?inserted?row,?or?-1?if?an?error?occurred?
?????*/??
????public?long?insert(NetTaskBuffer?pojo)?{??
????????SQLiteDatabase?db?=?getWritableDatabase();//?獲取可寫SQLiteDatabase對象??
????????iniContentValues(pojo);?//?ContentValues類似map，存入的是鍵值對??
????????long?result?=?db.insert(tableName,?null,?contentValues);??
????????if?(result?!=?-1)?{??
????????????pojo.id?=?(int)?result;??
????????}??
????????db.close();??
????????return?result;??
????}??
??
????/**?
?????*?根據ID更新記錄的，跟插入的很像?
?????*??
?????*?@return?the?number?of?rows?affected?
?????*??
?????*/??
????public?int?update(NetTaskBuffer?pojo)?{??
????????SQLiteDatabase?db?=?getWritableDatabase();??
????????iniContentValues(pojo);?//?初始化鍵值對??
????????int?result?=?db.update(tableName,?contentValues,?"id=?",??
????????????????new?String[]?{?pojo.id?+?""?});??
????????db.close();??
????????return?result;??
????}??
??
}??

安卓標準數據庫構建.zip?(9.2 KB)

轉載于:https://www.cnblogs.com/dongweiq/p/4045077.html

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