Android SQLite 开发教程(5): 导出数据库到XML文件

使用SQLiteOpenHelper 创建的数据库为应用程序私有，其路径一般为DATA/data/APP_NAME/databases/FILENAME

DATA 为使用Environment.getDataDirectory()返回的路径，一般为你的SD卡的路径。
APP_Name为你的应用的名称
FILENAME为你的数据库的文件名
其它程序一般无法访问这个文件，因此也给调试带来了不便，当然你可以使用Android SDK 的sqlite3 工具来直接访问这个数据，但个人还是觉的sqlite 使用起来不是十分方便。

你也可以将数据库创建者SD卡上面，此时可以使用SQLiteDatabase 的openOrCreateDatabase 指定要创建的数据库的文件名（指定SD卡上的某个文件名）。

也可以将数据库使用代码复制到SD卡上。此时可以使用一些桌面系统上的SQLite管理工具，比如Firefox 的SQL Lite manager 插件来访问这个数据库。

一种简洁的方法是将数据库导出到XML文件，下面类DatabaseDump的实现，可以将如何一个数据库所有表和表的内容导出到XML文件中

[java]
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

class DatabaseDump {

public DatabaseDump(SQLiteDatabase db,String destXml) {
mDb = db;
mDestXmlFilename=destXml;

try {
// create a file on the sdcard to export the
// database contents to
File myFile = new File(mDestXmlFilename);
myFile.createNewFile();

FileOutputStream fOut = new FileOutputStream(myFile);
BufferedOutputStream bos = new BufferedOutputStream(fOut);

mExporter = new Exporter(bos);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

public void exportData() {

try {
mExporter.startDbExport(mDb.getPath());

// get the tables out of the given sqlite database
String sql = "SELECT * FROM sqlite_master";

Cursor cur = mDb.rawQuery(sql, new String[0]);
cur.moveToFirst();

String tableName;
while (cur.getPosition() < cur.getCount()) {
tableName = cur.getString(cur.getColumnIndex("name"));

// don't process these two tables since they are used
// for metadata
if (!tableName.equals("android_metadata")
&& !tableName.equals("sqlite_sequence")) {
exportTable(tableName);
}

cur.moveToNext();
}
mExporter.endDbExport();
mExporter.close();
} catch (IOException e) {
e.printStackTrace();
}
}

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();
}

private String mDestXmlFilename = "/sdcard/export.xml";

private SQLiteDatabase mDb;
private Exporter mExporter;

class Exporter {
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 Exporter() throws FileNotFoundException {
this(new BufferedOutputStream(new FileOutputStream(mDestXmlFilename)));

}

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

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

public void startDbExport(String dbName) throws IOException {
String stg = START_DB + dbName + CLOSING_WITH_TICK;
mbufferos.write(stg.getBytes());
}

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

public void startTable(String tableName) throws IOException {
String stg = START_TABLE + tableName + CLOSING_WITH_TICK;
mbufferos.write(stg.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 {
String stg = START_COL + name + CLOSING_WITH_TICK + val + END_COL;
mbufferos.write(stg.getBytes());
}
}

}

补充：移动开发 , Android ,