事物处理
PersonService
Java代码
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 | package org.wp.service; /** * * 使用SQLiteDatabase的beginTransaction()方法可以开启一个事务 * 程序执行到endTransaction() 方法时会检查事务的标志是否为成功 * 如果为成功则提交事务，否则回滚事务 * 当应用需要提交事务，必须在程序执行到endTransaction()方法之前 * 使用setTransactionSuccessful() 方法设置事务的标志为成功 * 如果不调用setTransactionSuccessful() 方法，默认会回滚事务 * */ import java.util.ArrayList; import java.util.List; import org.wp.domain.Person; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.util.Log; public class PersonService { private static final String TAG = "PersonService"; private DataBaseOpenHelper dataBaseOpenHelper; private SQLiteDatabase database; public PersonService(Context context) { dataBaseOpenHelper = new DataBaseOpenHelper(context); } public void save() { database = dataBaseOpenHelper.getWritableDatabase(); // 开始事务 database.beginTransaction(); try { database.execSQL("insert into person(name,age) values(?,?)", new Object[] { "张三", (short) 26 }); database.execSQL("insert into person(name,age) values(?,?)", new Object[] { "田七", (short) 35 }); // 调用此方法会在执行到endTransaction() 时提交当前事务，如果不调用此方法会回滚事务 database.setTransactionSuccessful(); } catch (Exception e) { Log.i(TAG, e.toString()); } // 由事务的标志决定是提交事务，还是回滚事务 database.endTransaction(); } public List<Person> getScrollData(int startResult, int maxResult) { List<Person> persons = new ArrayList<Person>(); database = dataBaseOpenHelper.getReadableDatabase(); Cursor cursor = database.rawQuery("select * from person limit ?,?", new String[] { String.valueOf(startResult), String.valueOf(maxResult) }); while (cursor.moveToNext()) { persons.add(new Person(cursor.getInt(0), cursor.getString(1), cursor.getShort(2))); } return persons; } } |
PersonServiceTest
Java代码
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | package org.wp.db; import java.util.List; import org.wp.domain.Person; import org.wp.service.PersonService; import android.test.AndroidTestCase; import android.util.Log; public class PersonServiceTest extends AndroidTestCase { private static final String TAG = "PersonServiceTest"; public void testSave() { PersonService personService = new PersonService(this.getContext()); personService.save(); } public void testGetScrollData() throws Exception { PersonService personService = new PersonService(this.getContext()); List<Person> persons = personService.getScrollData(0, 30); for (Person person : persons) { Log.i(TAG, person.toString()); } } } |