经常用得到的安卓数据库基类

//创建数据库
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();
}
}

// 缓存
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,"); // 这一列不能修改
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());
}

// 插入语句,初始化数据库使用
private static void insert_SQL(SQLiteDatabase db) {

}
}



//----------------------数据库操作基类--------------------------------------//


/**
 * 数据库基本操作类,数据库的创建,更新的操作都在这里进行
 *
 * @author yizhe
 * @date 2014-9-11
 */
public abstract class DBHelper extends SQLiteOpenHelper {

static String name = "hk.db"; // 数据库名称
static CursorFactory cursorFactory = null;
static int version = 1000;// 初始版本:1000
Context context;

protected ContentValues contentValues; // cursor对象转行中介,给子类使用

protected String tableName;

protected DBHelper(Context context, String tableName) {
super(context, name, cursorFactory, version);
this.context = context;
this.tableName = tableName;
}

/**
     * 软件第一次安装的时候会调用,覆盖安装不会调用
     */
public void onCreate(SQLiteDatabase db) {
// 所有表的创建过程都在这里进行
DBCreate.createDatabase(db);
}

/**
     * 覆盖安装,当版本号version发生变化的时候,这个方法才会被调用,而且只执行一次
     */
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
onCreate(db);
// if (oldVersion < 109) {
// onCreate(db);
// } else {
// }
}

/**
     * 每次成功打开数据库后首先被执行
     */
public void onOpen(SQLiteDatabase db) {
super.onOpen(db); // 每次成功打开数据库后首先被执行
}

public void finalize() {
close();
}

// --------------------------sql方法---------------------------------//
/**
     * 执行sql,没有返回
     */
public void execSQL(String sql) {
System.out.println("==execSQL==" + sql);
SQLiteDatabase db = getWritableDatabase();
db.execSQL(sql);
db.close();
}

/**
     * 批量执行sql,内部启用事务
     *
     * @param list
     *            sql列表
     * @return 是否执行成功
     */
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;
}

/**
     * 根据id删除记录
     *
     * @param id
     *            表中必须有"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;
}

/**
     * 删除: 只需要写where 条件(不带where) 和 参数
     *
     * @param whereStr
     *            例如: "id=?"
     * @param arr
     *            例如: new String[] { "123" }
     * @return 受影响的行
     */
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();
}

/**
     * 通用查询,多用于事务中
     */
public static Cursor Query(SQLiteDatabase db, String sql) {
System.out.println("==Query==" + sql);
return db.rawQuery(sql, new String[] {});
}

/**
     * 通用执行sql,,多用于事务中
     *
     */
public static void execSQL(SQLiteDatabase db, String sql) {
System.out.println("==execSQL==" + sql);
db.execSQL(sql);
}

}

//-------------------------下面是一个具体实现的DEMO-------------------------------//
/**
 * dao类,实现基本的数据库操作<br/>
 * 需要保存到数据库中的对象的属性不能使用基本类型,建议只使用Integer 和 String<br/>
 * 做为通用对象,从demo创建只要修改tableName即可
 *
 * @author yizhe
 * @date 2012-5-18
 */
public class NetTaskBufferDao extends DBHelper {
int expiryDays = 10; // 数据缓存有效期

public NetTaskBufferDao(Context context) {
super(context, "NetTaskBuffer");
}

// pojo的整数都需要使用Long类型 或者Integer类型 建议使用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;
}

// --------------------自定义方法--------------------------------//
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 });
}

// --------------------基础方法---------------------------------//

/**
     * 根据sql获取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;
}

/**
     * 根据ID获取一条记录
     */
public NetTaskBuffer getById(int id) {
String sql = "select * from " + tableName + " where id=" + id;
return getOneAsSQL(sql, null);
}

/**
     * 返回结果中的提一条记录
     */
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;
}

/**
     * 保存对象到数据库,自动判断插入还是更像
     *
     * @return 返回更新的记录数,或者 插入数据的id,如果返回值<=0表示失败
     */
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;
}

/**
     * 添加数据,自动插入id
     *
     * @return the row ID of the newly inserted row, or -1 if an error occurred
     */
public long insert(NetTaskBuffer pojo) {
SQLiteDatabase db = getWritableDatabase();// 获取可写SQLiteDatabase对象
iniContentValues(pojo); // ContentValues类似map，存入的是键值对
long result = db.insert(tableName, null, contentValues);
if (result != -1) {
pojo.id = (int) result;
}
db.close();
return result;
}

/**
     * 根据ID更新记录的，跟插入的很像
     *
     * @return the number of rows affected
     *
     */
public int update(NetTaskBuffer pojo) {
SQLiteDatabase db = getWritableDatabase();
iniContentValues(pojo); // 初始化键值对
int result = db.update(tableName, contentValues, "id=?",
new String[] { pojo.id + "" });
db.close();
return result;
}

}

安卓标准数据库构建.zip (9.2 KB)