android dbutils的简化版，androiddbutils,//复杂的可以使用dbu

android dbutils的简化版，androiddbutils,//复杂的可以使用dbu

//复杂的可以使用dbutils的，这就来个仿dbutils的简化版的吧public class DAOHelper {public static final MapRowProcessor MAPROWPROCESSOR = new MapRowProcessor();private String tableName;   //表名private String[] cols;   //列名public DAOHelper(String tableName, String[] columns) {this.tableName = tableName;this.cols = columns;}public List<Map<String, String>> query(String sqlWhere) {return query(sqlWhere,null);}public List<Map<String, String>> query(String sqlWhere,String[] sqlWhereArgs) {ArrayList<Map<String, String>> list = new ArrayList<Map<String, String>>(0);Cursor cursor = null;try {SQLiteDatabase database = DBOpenHelper.getWritableDatabase();cursor = database.query(tableName, cols, sqlWhere, sqlWhereArgs, null, null, null);list.ensureCapacity(cursor.getCount());while (cursor.moveToNext()) {list.add(MAPROWPROCESSOR.process(cursor));}} catch (Exception e) {Logger.error("DAOHelper", "插入失败");} finally {if (null != cursor) {cursor.close();}}return list;}public int insert(List<Map<String, String>> list) {SQLiteDatabase database = DBOpenHelper.getWritableDatabase();try {// 打开数据库database.beginTransaction();for (Map<String, String> map : list) {ContentValues v = mapToContentValues(map);database.insert(tableName, null, v);if (v != null) {v.clear();v = null;}}// 设置事务成功.database.setTransactionSuccessful();return list.size();} catch (Exception e) {Logger.error("DAOHelper", "插入失败");return -1;} finally {database.endTransaction();}}public int delete(String sqlWhere) {SQLiteDatabase database = DBOpenHelper.getWritableDatabase();try {// 打开数据库database.beginTransaction();// 设置事务成功.int rowCount = database.delete(tableName, sqlWhere, null);database.setTransactionSuccessful();return rowCount;} catch (Exception e) {Logger.error("DAOHelper", "删除失败");return -1;} finally {database.endTransaction();}}private ContentValues mapToContentValues(Map<String, String> map) {ContentValues values = new ContentValues();for (String col : cols) {values.put(col, map.get(col));}return values;}static public void clear(List<Map<String, String>> list) {if (null == list) {return;}for (Map<String, String> map : list) {if (null != map) {map.clear();}}list.clear();}/*** 查询得到列表* * @param sql*            　完整的select语句，可包含?，但不能用;结尾* @param selectionArgs*            　查询参数* @param rp*            　　每行的处理，可使用DAOHelper.MAPROWPROCESSOR* @return*/static public <T> List<T> query(String sql, String[] selectionArgs, RowProcessor<T> rp) {ArrayList<T> list = new ArrayList<T>(0);Cursor c = null;try {SQLiteDatabase database = DBOpenHelper.getWritableDatabase();c = database.rawQuery(sql, selectionArgs);list.ensureCapacity(c.getCount());while (c.moveToNext()) {list.add(rp.process(c));}} catch (Exception e) {e.printStackTrace();Logger.error("DAOHelper", "查询失败\\n"+e);} finally {if (null != c) {c.close();}}return list;}static public int count(String sql, String[] selectionArgs) {Cursor c = null;try {SQLiteDatabase database = DBOpenHelper.getWritableDatabase();c = database.rawQuery(sql, selectionArgs);return c.getCount();} catch (Exception e) {e.printStackTrace();Logger.error("DAOHelper", "查询失败\\n"+e);} finally {if (null != c) {c.close();}}return 0;}//行处理接口public interface RowProcessor<T> {T process(Cursor c);}//将每行处理成Map<String,String>结构static public class MapRowProcessor implements RowProcessor<Map<String,String>> {@Overridepublic Map<String,String> process(Cursor c) {Map<String,String> map = new CaseInsensitiveMap<String>();String[] columns = c.getColumnNames();for (String col : columns) {map.put(col, c.getString(c.getColumnIndex(col)));}return map;}}//将每行处理成String结构static public class StringRowProcessor implements RowProcessor<String> {private String[] fields;private String joinner;private volatile int[] fldIdx = null;public StringRowProcessor(){this.fields = null;this.joinner = ",";}public StringRowProcessor(String[] fields,String joinner){this.fields = fields;if(null != joinner){this.joinner = joinner;}}public StringRowProcessor(int[] fieldIndex,String joinner){fldIdx = fieldIndex;if(null != joinner){this.joinner = joinner;}}@Overridepublic String process(Cursor c) {if(null == fldIdx){initFldIdx(c);}StringBuilder builder = new StringBuilder();for(int i = 0,n = fldIdx.length; i < n; i ++){builder.append(c.getString(fldIdx[i]));if(i < n -1){builder.append(joinner);}}return builder.toString();}private void initFldIdx(Cursor c) {if(null == fields){for(int i = 0,n = c.getColumnCount(); i < n ; i ++ ){fldIdx[i] = i;}}else{for(int i = 0, n = fields.length; i < n; i ++){fldIdx[i] = c.getColumnIndex(fields[i]);}}}}}