Person實(shí)體類(lèi)：
package com.ljq.domain;public class Person { PRivate Integer id; private String name; private String phone; public Person() { super(); } public Person(String name, String phone) { super(); this.name = name; this.phone = phone; } public Person(Integer id, String name, String phone) { super(); this.id = id; this.name = name; this.phone = phone; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; }}DBOpenHelper數(shù)據(jù)庫(kù)關(guān)聯(lián)類(lèi)：
package com.ljq.db;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;public class DBOpenHelper extends SQLiteOpenHelper { // 類(lèi)沒(méi)有實(shí)例化,是不能用作父類(lèi)構(gòu)造器的參數(shù),必須聲明為靜態(tài) private static final String DBNAME = "ljq.db"; private static final int VERSION = 1; // 第三個(gè)參數(shù)CursorFactory指定在執(zhí)行查詢(xún)時(shí)獲得一個(gè)游標(biāo)實(shí)例的工廠類(lèi), // 設(shè)置為null,代表使用系統(tǒng)默認(rèn)的工廠類(lèi) public DBOpenHelper(Context context) { super(context, DBNAME, null, VERSION); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE PERSON (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME VARCHAR(20), PHONE VARCHAR(20))"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // 注：生產(chǎn)環(huán)境上不能做刪除操作 db.execSQL("DROP TABLE IF EXISTS PERSON"); onCreate(db); }}PersonService業(yè)務(wù)類(lèi)：
package com.ljq.db;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.database.Cursor;import com.ljq.domain.Person;public class PersonService { private DBOpenHelper dbOpenHelper = null; /** * 構(gòu)造函數(shù) * * 調(diào)用getWritableDatabase()或getReadableDatabase()方法后，會(huì)緩存SQLiteDatabase實(shí)例； * 因?yàn)檫@里是手機(jī)應(yīng)用程序，一般只有一個(gè)用戶(hù)訪問(wèn)數(shù)據(jù)庫(kù)，所以建議不關(guān)閉數(shù)據(jù)庫(kù)，保持連接狀態(tài)。 * getWritableDatabase()，getReadableDatabase的區(qū)別是當(dāng)數(shù)據(jù)庫(kù)寫(xiě)滿時(shí)，調(diào)用前者會(huì)報(bào)錯(cuò)，調(diào)用后者不會(huì)， * 所以如果不是更新數(shù)據(jù)庫(kù)的話，最好調(diào)用后者來(lái)獲得數(shù)據(jù)庫(kù)連接。 * * 對(duì)于熟悉SQL語(yǔ)句的程序員最好使用exeSQL(),rawQuery(),因?yàn)楸容^直觀明了 * * @param context */ public PersonService(Context context){ dbOpenHelper = new DBOpenHelper(context); } public void save(Person person){ dbOpenHelper.getWritableDatabase().execSQL("insert into person(name, phone) values (?, ?)", new Object[]{person.getName(), person.getPhone()}); } public void update(Person person){ dbOpenHelper.getWritableDatabase().execSQL("update person set name=?, phone=? where id=?", new Object[]{person.getName(), person.getPhone(), person.getId()}); } public void delete(Integer... ids){ if(ids.length>0){ StringBuffer sb = new StringBuffer(); for(Integer id : ids){ sb.append("?").append(","); } sb.deleteCharAt(sb.length() - 1); dbOpenHelper.getWritableDatabase().execSQL("delete from person where id in ("+sb+")", (Object[])ids); } } public Person find(Integer id){ Cursor cursor = dbOpenHelper.getReadableDatabase().rawQuery("select id, name, phone from person where id=?", new String[]{String.valueOf(id)}); if(cursor.moveToNext()){ int personid = cursor.getInt(0); String name = cursor.getString(1); String phone = cursor.getString(2); return new Person(personid, name, phone); } return null; } public long getCount(){ Cursor cursor = dbOpenHelper.getReadableDatabase().query("person", new String[]{"count(*)"}, null,null,null,null,null); if(cursor.moveToNext()){ return cursor.getLong(0); } return 0; } /** * 分頁(yè) * * @param startResult 偏移量，默認(rèn)從0開(kāi)始 * @param maxResult 每頁(yè)顯示的條數(shù) * @return */ public List<Person> getScrollData(int startResult, int maxResult){ List<Person> persons = new ArrayList<Person>(); //Cursor cursor = dbOpenHelper.getReadableDatabase().query("person", new String[]{"id, name, phone"}, // "name like ?", new String[]{"%ljq%"}, null, null, "id desc", "1,2"); Cursor cursor = dbOpenHelper.getReadableDatabase().rawQuery("select * from person limit ?,?", new String[]{String.valueOf(startResult), String.valueOf(maxResult)}); while(cursor.moveToNext()) { int personid = cursor.getInt(0); String name = cursor.getString(1); String phone = cursor.getString(2); persons.add(new Person(personid, name, phone)); } return persons; }}PersonServiceTest測(cè)試類(lèi)
package com.ljq.test;import java.util.List;import com.ljq.db.PersonService;import com.ljq.domain.Person;import android.test.AndroidTestCase;import android.util.Log;public class PersonServiceTest extends AndroidTestCase{ private final String TAG = "PersonServiceTest"; public void testSave() throws Exception{ PersonService personService = new PersonService(this.getContext()); personService.save(new Person("zhangsan1", "059188893343")); personService.save(new Person("zhangsan2", "059188893343")); personService.save(new Person("zhangsan3", "059188893343")); personService.save(new Person("zhangsan4", "059188893343")); personService.save(new Person("zhangsan5", "059188893343")); } public void testUpdate() throws Exception{ PersonService personService = new PersonService(this.getContext()); Person person = personService.find(1); person.setName("linjiqin"); personService.update(person); } public void testFind() throws Exception{ PersonService personService = new PersonService(this.getContext()); Person person = personService.find(1); Log.i(TAG, person.getName()); } public void testList() throws Exception{ PersonService personService = new PersonService(this.getContext()); List<Person> persons = personService.getScrollData(0, 10); for(Person person : persons){ Log.i(TAG, person.getId() + " : " + person.getName()); } } public void testCount() throws Exception{ PersonService personService = new PersonService(this.getContext()); Log.i(TAG, String.valueOf(personService.getCount())); } public void testDelete() throws Exception{ PersonService personService = new PersonService(this.getContext()); personService.delete(1); } public void testDeleteMore() throws Exception{ PersonService personService = new PersonService(this.getContext()); personService.delete(new Integer[]{2, 5, 6}); }}新聞熱點(diǎn)
疑難解答
圖片精選
網(wǎng)友關(guān)注
