我花了几天时间寻找如何将数据库导出为 xml 或文本文件，但似乎找不到我要找的东西。我遇到的所有教程和代码片段似乎并没有真正解释我正在寻找的内容。
这种风格我该如何导出？
public class DataXmlExporter extends DataBaseDemoActivity {
static final String DATASUBDIRECTORY = "bookwormdata";
// private final SQLiteDatabase db;
private XmlBuilder xmlBuilder;
Button butt;
/* public DataXmlExporter(final SQLiteDatabase db) {
this.db = db;
}*/
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main7);
butt=(Button)findViewById(R.id.exportxml);
String exportFileNamePrefix=exportxml;
// public void export(final String dbName, final String exportFileNamePrefix) throws IOException {
Log.i(Constants._COUNT, "exporting database - " + dbname + " exportFileNamePrefix=" + exportFileNamePrefix);
try {
xmlBuilder = new XmlBuilder();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
xmlBuilder.start(dbname);
// get the tables
String sql = "select * from dept";
Cursor c = db.rawQuery(sql, new String[0]);
if (c.moveToFirst()) {
//while (c.moveToNext()) {
String tableName ="dept";//c.getString(c.getColumnIndex("dep_id"));
// skip metadata, sequence, and uidx (unique indexes)
if (!tableName.equals("android_metadata") && !tableName.equals("sqlite_sequence")
&& !tableName.startsWith("uidx")) {
try {
exportTable(tableName);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// }
}
String xmlString = null;
try {
xmlString = xmlBuilder.end();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
writeToFile(xmlString, exportFileNamePrefix + ".xml");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.i(Constants._COUNT, "exporting database complete");
Toast.makeText(DataXmlExporter.this, "DB xml backup Successfully", 2000).show();
butt.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent(DataXmlExporter.this, DataBaseDemoActivity.class);
startActivity(intent);
}
});
}
private void exportTable(final String tableName) throws IOException {
xmlBuilder.openTable(tableName);
String sql = "select * from " + tableName;
Cursor c = db.rawQuery(sql, new String[0]);
if (c.moveToFirst()) {
int cols = c.getColumnCount();
do {
xmlBuilder.openRow();
for (int i = 0; i < cols; i++) {
/*if(i==6)
{
//String id = c.getString( c.getColumnIndex("photo"));
String str = new String(image);
xmlBuilder.addColumn(c.getColumnName(i), str);
}*/
xmlBuilder.addColumn(c.getColumnName(i), c.getString(i));
}
xmlBuilder.closeRow();
} while (c.moveToNext());
}
c.close();
xmlBuilder.closeTable();
}
private void writeToFile(final String xmlString, final String exportFileName) throws IOException {
File dir = new File(Environment.getExternalStorageDirectory(), DataXmlExporter.DATASUBDIRECTORY);
if (!dir.exists()) {
dir.mkdirs();
}
File file = new File(dir, exportFileName);
file.createNewFile();
ByteBuffer buff = ByteBuffer.wrap(xmlString.getBytes());
FileChannel channel = new FileOutputStream(file).getChannel();
try {
channel.write(buff);
} finally {
if (channel != null) {
channel.close();
}
}
}
/**
* XmlBuilder is used to write XML tags (open and close, and a few attributes)
* to a StringBuilder. Here we have nothing to do with IO or SQL, just a fancy StringBuilder.
*
* @author ccollins
*
*/
static class XmlBuilder {
private static final String OPEN_XML_STANZA = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";
private static final String CLOSE_WITH_TICK = "'>";
private static final String DB_OPEN = "<database name='";
private static final String DB_CLOSE = "</database>";
private static final String TABLE_OPEN = "<table name='";
private static final String TABLE_CLOSE = "</table>";
private static final String ROW_OPEN = "<row>";
private static final String ROW_CLOSE = "</row>";
private static final String COL_OPEN = "<col name='";
private static final String COL_CLOSE = "</col>";
private final StringBuilder sb;
public XmlBuilder() throws IOException {
sb = new StringBuilder();
}
void start(final String dbName) {
sb.append(XmlBuilder.OPEN_XML_STANZA);
sb.append(XmlBuilder.DB_OPEN + dbName + XmlBuilder.CLOSE_WITH_TICK);
}
String end() throws IOException {
sb.append(XmlBuilder.DB_CLOSE);
return sb.toString();
}
void openTable(final String tableName) {
sb.append(XmlBuilder.TABLE_OPEN + tableName + XmlBuilder.CLOSE_WITH_TICK);
}
void closeTable() {
sb.append(XmlBuilder.TABLE_CLOSE);
}
void openRow() {
sb.append(XmlBuilder.ROW_OPEN);
}
void closeRow() {
sb.append(XmlBuilder.ROW_CLOSE);
}
void addColumn(final String name, final String val) throws IOException {
sb.append(XmlBuilder.COL_OPEN + name + XmlBuilder.CLOSE_WITH_TICK + val + XmlBuilder.COL_CLOSE);
}
}
}
试试这个。这对我来说是工作。