鉴于经常使用 Sqlite 数据库做数据持久化处理，进行了一点封装，方便使用。
该封装类主要支持一下功能
- 支持多用户数据储存
- 支持 Sqlite数据库升级
- 支持传入 Sql 语句建表
- 支持 SQLiteDatabase 基本操作。比如：execSQL、rawQuery、insert等等
- 解决了数据库并发问题
先贴上封装类代码
/**
*
* @ClassName: DataBaseOpenHelper
* @Description: 数据库工具类
* @author lhy
* @date 2014-10-9 下午2:36:41
*
*/
public class DataBaseOpenHelper extends SQLiteOpenHelper {
private static Map<String, DataBaseOpenHelper> dbMaps = new HashMap<String, DataBaseOpenHelper>();
private OnSqliteUpdateListener onSqliteUpdateListener;
/**
* 建表语句列表
*/
private List<String> createTableList;
private String nowDbName;
private DataBaseOpenHelper(Context context, String dbName, int dbVersion, List<String> tableSqls) {
super(context, dbName, null, dbVersion);
nowDbName = dbName;
createTableList = new ArrayList<String>();
createTableList.addAll(tableSqls);
}
/**
*
* @Title: getInstance
* @Description: 获取数据库实例
* @param @param context
* @param @param userId
* @param @return
* @return DataBaseOpenHelper
* @author lihy
*/
public static DataBaseOpenHelper getInstance(Context context, String dbName, int dbVersion, List<String> tableSqls) {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(dbName);
if (dataBaseOpenHelper == null) {
dataBaseOpenHelper = new DataBaseOpenHelper(context, dbName, dbVersion, tableSqls);
}
dbMaps.put(dbName, dataBaseOpenHelper);
return dataBaseOpenHelper;
};
@Override
public void onCreate(SQLiteDatabase db) {
for (String sqlString : createTableList) {
db.execSQL(sqlString);
}
}
/**
*
* @Title: execSQL
* @Description: Sql写入
* @param @param sql
* @param @param bindArgs
* @return void
* @author lihy
*/
public void execSQL(String sql, Object[] bindArgs) {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(nowDbName);
synchronized (dataBaseOpenHelper) {
SQLiteDatabase database = dataBaseOpenHelper.getWritableDatabase();
database.execSQL(sql, bindArgs);
}
}
/**
*
* @Title: rawQuery
* @Description:
* @param @param sql查询
* @param @param bindArgs
* @param @return
* @return Cursor
* @author lihy
*/
public Cursor rawQuery(String sql, String[] bindArgs) {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(nowDbName);
synchronized (dataBaseOpenHelper) {
SQLiteDatabase database = dataBaseOpenHelper.getReadableDatabase();
Cursor cursor = database.rawQuery(sql, bindArgs);
return cursor;
}
}
/**
*
* @Title: insert
* @Description: 插入数据
* @param @param table
* @param @param contentValues 设定文件
* @return void 返回类型
* @author lihy
* @throws
*/
public void insert(String table, ContentValues contentValues) {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(nowDbName);
synchronized (dataBaseOpenHelper) {
SQLiteDatabase database = dataBaseOpenHelper.getWritableDatabase();
database.insert(table, null, contentValues);
}
}
/**
*
* @Title: update
* @Description: 更新
* @param @param table
* @param @param values
* @param @param whereClause
* @param @param whereArgs 设定文件
* @return void 返回类型
* @throws
*/
public void update(String table, ContentValues values, String whereClause, String[] whereArgs) {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(nowDbName);
synchronized (dataBaseOpenHelper) {
SQLiteDatabase database = dataBaseOpenHelper.getWritableDatabase();
database.update(table, values, whereClause, whereArgs);
}
}
/**
*
* @Title: delete
* @Description:删除
* @param @param table
* @param @param whereClause
* @param @param whereArgs
* @return void
* @author lihy
*/
public void delete(String table, String whereClause, String[] whereArgs) {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(nowDbName);
synchronized (dataBaseOpenHelper) {
SQLiteDatabase database = dataBaseOpenHelper.getWritableDatabase();
database.delete(table, whereClause, whereArgs);
}
}
/**
*
* @Title: query
* @Description: 查
* @param @param table
* @param @param columns
* @param @param selection
* @param @param selectionArgs
* @param @param groupBy
* @param @param having
* @param @param orderBy
* @return void
* @author lihy
*/
public Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having,
String orderBy) {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(nowDbName);
synchronized (dataBaseOpenHelper) {
SQLiteDatabase database = dataBaseOpenHelper.getReadableDatabase();
// Cursor cursor = database.rawQuery("select * from "
// + TableName.TABLE_NAME_USER + " where userId =" + userId, null);
Cursor cursor = database.query(table, columns, selection, selectionArgs, groupBy, having, orderBy);
return cursor;
}
}
/**
*
* @Description:查
* @param table
* @param columns
* @param selection
* @param selectionArgs
* @param groupBy
* @param having
* @param orderBy
* @param limit
* @return
* Cursor
* @exception:
* @author: lihy
* @time:2015-4-3 上午9:37:29
*/
public Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having,
String orderBy,String limit) {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(nowDbName);
synchronized (dataBaseOpenHelper) {
SQLiteDatabase database = dataBaseOpenHelper.getReadableDatabase();
// Cursor cursor = database.rawQuery("select * from "
// + TableName.TABLE_NAME_USER + " where userId =" + userId, null);
Cursor cursor = database.query(table, columns, selection, selectionArgs, groupBy, having, orderBy, limit);
return cursor;
}
}
/**
*
* @Description 查询，方法重载,table表名，sqlString条件
* @param @return
* @return Cursor
* @author lihy
*/
public Cursor query(String tableName, String sqlString) {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(nowDbName);
synchronized (dataBaseOpenHelper) {
SQLiteDatabase database = dataBaseOpenHelper.getReadableDatabase();
Cursor cursor = database.rawQuery("select * from " + tableName + " " + sqlString, null);
return cursor;
}
}
/**
* @see android.database.sqlite.SQLiteOpenHelper#close()
*/
public void clear() {
DataBaseOpenHelper dataBaseOpenHelper = dbMaps.get(nowDbName);
dataBaseOpenHelper.close();
dbMaps.remove(dataBaseOpenHelper);
}
/**
* onUpgrade()方法在数据库版本每次发生变化时都会把用户手机上的数据库表删除，然后再重新创建。<br/>
* 一般在实际项目中是不能这样做的，正确的做法是在更新数据库表结构时，还要考虑用户存放于数据库中的数据不会丢失,从版本几更新到版本几。(非
* Javadoc)
*
* @see android.database.sqlite.SQLiteOpenHelper#onUpgrade(android.database.sqlite
* .SQLiteDatabase, int, int)
*/
@Override
public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {
if (onSqliteUpdateListener != null) {
onSqliteUpdateListener.onSqliteUpdateListener(db, arg1, arg2);
}
}
public void setOnSqliteUpdateListener(OnSqliteUpdateListener onSqliteUpdateListener) {
this.onSqliteUpdateListener = onSqliteUpdateListener;
}
}
数据库更新接口代码
public interface OnSqliteUpdateListener {
public void onSqliteUpdateListener(SQLiteDatabase db, int oldVersion, int newVersion);
}