sqlite工具类

package com.asc.db;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;/** * 数据库公共类，提供基本数据库操作 *  * @author raymon *  */public class DBManager {// 默认数据库private static final String DB_NAME = "asc.db";// 数据库版本private static final int DB_VERSION = 1;// 执行open()打开数据库时，保存返回的数据库对象private SQLiteDatabase mSQLiteDatabase = null;// 由SQLiteOpenHelper继承过来private DatabaseHelper mDatabaseHelper = null;// 本地Context对象private Context mContext = null;private static DBManager dbConn= null;// 查询游标对象private Cursor cursor;/** * SQLiteOpenHelper内部类 */private static class DatabaseHelper extends SQLiteOpenHelper {DatabaseHelper(Context context) {// 当调用getWritableDatabase()或 getReadableDatabase()方法时,创建一个数据库super(context, DB_NAME, null, DB_VERSION);}@Overridepublic void onCreate(SQLiteDatabase db) {db.execSQL("CREATE TABLE ad_record(id PRIMARY KEY NOT NULL, adUrl TEXT, apMac TEXT, createDate DATETIME);");}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {db.execSQL("DROP TABLE IF EXISTS ad_record");onCreate(db);}}/** * 构造函数 *  * @param mContext */private DBManager(Context mContext) {super();this.mContext = mContext;}public static DBManager getInstance(Context mContext){if (null == dbConn) {dbConn = new DBManager(mContext);}return dbConn;}/** * 打开数据库 */public void open() {mDatabaseHelper = new DatabaseHelper(mContext);mSQLiteDatabase = mDatabaseHelper.getWritableDatabase();}/** * 关闭数据库 */public void close() {if (null != mDatabaseHelper) {mDatabaseHelper.close();}if (null != cursor) {cursor.close();}}/** * 插入数据 * @param tableName 表名 * @param nullColumn null * @param contentValues 名值对 * @return 新插入数据的ID，错误返回-1 * @throws Exception */public long insert(String tableName, String nullColumn,ContentValues contentValues) throws Exception {try {return mSQLiteDatabase.insert(tableName, nullColumn, contentValues);} catch (Exception e) {throw e;}}/** * 通过主键ID删除数据 * @param tableName 表名 * @param key 主键名 * @param id 主键值 * @return 受影响的记录数 * @throws Exception */public long delete(String tableName, String key, int id) throws Exception {try {return mSQLiteDatabase.delete(tableName, key + " = " + id, null);} catch (Exception e) {throw e;}}/** * 查找表的所有数据 * @param tableName 表名 * @param columns 如果返回所有列，则填null * @return * @throws Exception */public Cursor findAll(String tableName, String [] columns) throws Exception{try {cursor = mSQLiteDatabase.query(tableName, columns, null, null, null, null, null);cursor.moveToFirst();return cursor;} catch (Exception e) {throw e;}}/** * 根据主键查找数据 * @param tableName 表名 * @param key 主键名 * @param id  主键值 * @param columns 如果返回所有列，则填null * @return Cursor游标 * @throws Exception  */public Cursor findById(String tableName, String key, int id, String [] columns) throws Exception {try {return mSQLiteDatabase.query(tableName, columns, key + " = " + id, null, null, null, null);} catch (Exception e) {throw e;}}/** * 根据条件查询数据 * @param tableName 表名 * @param names 查询条件 * @param values 查询条件值 * @param columns 如果返回所有列，则填null * @param orderColumn 排序的列 * @param limit 限制返回数 * @return Cursor游标 * @throws Exception */public Cursor find(String tableName, String [] names, String [] values, String [] columns, String orderColumn, String limit) throws Exception{try {StringBuffer selection = new StringBuffer();for (int i = 0; i < names.length; i++) {selection.append(names[i]);selection.append(" = ?");if (i != names.length - 1) {selection.append(",");}}cursor = mSQLiteDatabase.query(true, tableName, columns, selection.toString(), values, null, null, orderColumn, limit);cursor.moveToFirst();return cursor;} catch (Exception e) {throw e;}}/** *  * @param tableName 表名 * @param names 查询条件 * @param values 查询条件值 * @param args 更新列-值对 * @return true或false * @throws Exception */public boolean udpate(String tableName, String [] names, String [] values, ContentValues args) throws Exception{try {StringBuffer selection = new StringBuffer();for (int i = 0; i < names.length; i++) {selection.append(names[i]);selection.append(" = ?");if (i != names.length - 1) {selection.append(",");}}return mSQLiteDatabase.update(tableName, args, selection.toString(), values) > 0;} catch (Exception e) {throw e;}}/** * 执行sql语句，包括创建表、删除、插入 *  * @param sql */public void executeSql(String sql) {mSQLiteDatabase.execSQL(sql);}}//转载请注明出处：http://forhope.iteye.com/blog/1461412