学步园

转载请注明出处：http://blog.csdn.net/krislight 

项目中遇到备份与还原App数据的需求,需要把DB数据备份到一个XML文件中,然后保存到SD卡上，还原的时候直接从XML文件解析数据进行insert DB动作。

现总结下实现方法,定义一个工具类

/**
 *  from sqlite to xml
 *  
 *  @author Kris
 */
public class DatabaseLog {

	// back up dir
	private String mDestXmlFileDir = "/psmd/appName/backup/";
	private SQLiteDatabase mDb;
	private Exporter mExporter;

	/**
	 * @param db  database
	 */
	public DatabaseLog(SQLiteDatabase db,String fileName) {
		mDb = db;
		try { 
			Calendar cal = Calendar.getInstance();
			//use date+time as filename e.g.  2013_04_03_13_23_49.backup
			if(TextUtils.isEmpty(fileName)){
	    	  fileName = cal.get(Calendar.YEAR)+"_"+cal.get(Calendar.MONTH)+"_"+cal.get(Calendar.DAY_OF_MONTH)+"_"
	    	   +cal.get(Calendar.HOUR_OF_DAY)+"_"+cal.get(Calendar.MINUTE)+"_"+cal.get(Calendar.MINUTE);
			}
			fileName += ".backup";
	    	File sdDir = Environment.getExternalStorageDirectory();
	    	File theDir = new File(sdDir, mDestXmlFileDir);
	        if (!theDir.exists()) {
	            theDir.mkdirs();
	        }
	        File picFile = new File(theDir, fileName);
	        picFile.createNewFile();
			FileOutputStream fOut = new FileOutputStream(picFile);
			BufferedOutputStream bos = new BufferedOutputStream(fOut);
			mExporter = new Exporter(bos);
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * export
	 */
	public void exportData() {
		try {
			//1.先查找icon存放的目录复制所有图片到備份目錄下面
            //  还原的时候检查这个栏位对应的文件是否存在,不存在则用backup下面的文件路径,然后update db
			mExporter.startDbExport(C_9510_PSMD_DBAdapter.DATABASE_NAME);
			//TODO export database and table
			exportTable("C_EVNT_EVNT");
			exportTable("C_EVNT_PSON");
			exportTable("R_EVNT_SEND");
			exportTable("R_EVNT_RECV");
			exportTable("C_TMPL_TYPE");
			exportTable("C_TMPL_EVDS");
			mExporter.endDbExport();
			mExporter.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

转载请注明出处：http://blog.csdn.net/krislight 

	/**
	 * 
	 * @param tableName
	 * @throws IOException
	 */
	private void exportTable(String tableName) throws IOException {
		mExporter.startTable(tableName);
		// get everything from the table
		String sql = "select * from " + tableName;
		Cursor cur = mDb.rawQuery(sql, new String[0]);
		int numcols = cur.getColumnCount();
		cur.moveToFirst();
		// move through the table, creating rows // and adding each column with
		// name and value
		// to the row
		while (cur.getPosition() < cur.getCount()) {
			mExporter.startRow();
			String name;
			String val;
			for (int idx = 0; idx < numcols; idx++) {
				name = cur.getColumnName(idx);
				val = cur.getString(idx);
				mExporter.addColumn(name, val);
			}
			mExporter.endRow();
			cur.moveToNext();
		}
		cur.close();
		mExporter.endTable();
	}

	
	public class Exporter {
		private static final String OPEN_XML_STANZA = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";
		private static final String CLOSING_WITH_TICK = "'>";
		private static final String START_DB = "<export-database name='";
		private static final String END_DB = "</export-database>";
		private static final String START_TABLE = "<table name='";
		private static final String END_TABLE = "</table>";
		private static final String START_ROW = "<row>";
		private static final String END_ROW = "</row>";
		private static final String START_COL = "<col name='";
		private static final String END_COL = "</col>";
		private BufferedOutputStream mbufferos;

		public String getFileName() {
			return "";

		}

		public Exporter(BufferedOutputStream bos) {
			mbufferos = bos;
		}

		public void close() throws IOException {
			if (mbufferos != null) {
				mbufferos.close();
			}
		}

		public void startDbExport(String dbName) throws IOException {
			StringBuffer sb = new StringBuffer();
			sb.append(OPEN_XML_STANZA).append(START_DB).append(dbName).append(CLOSING_WITH_TICK);
			mbufferos.write(sb.toString().getBytes());
		}

		public void endDbExport() throws IOException {
			mbufferos.write(END_DB.getBytes());
		}

		public void startTable(String tableName) throws IOException {
			StringBuffer sb = new StringBuffer();
			sb.append(START_TABLE).append(tableName).append(CLOSING_WITH_TICK);
			mbufferos.write(sb.toString().getBytes());
		}

		public void endTable() throws IOException {
			mbufferos.write(END_TABLE.getBytes());
		}

		public void startRow() throws IOException {
			mbufferos.write(START_ROW.getBytes());
		}

		public void endRow() throws IOException {
			mbufferos.write(END_ROW.getBytes());
		}

		public void addColumn(String name, String val) throws IOException {
			StringBuffer sb = new StringBuffer();
			sb.append(START_COL).append(name).append(CLOSING_WITH_TICK).append(val).append(END_COL);
			mbufferos.write(sb.toString().getBytes());
		}
	}
}