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Android SQLite数据库增删改查操作的案例分析

  • 时间:2020-01-02 14:32 编辑: 来源: 阅读:
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摘要:Android SQLite数据库增删改查操作的案例分析
[b]Person实体类 [/b]
[u]复制代码[/u] 代码如下:
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;     } }
[b]DBOpenHelper数据库关联类 [/b]
[u]复制代码[/u] 代码如下:
package com.ljq.db; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; public class DBOpenHelper extends SQLiteOpenHelper {     // 类没有实例化,是不能用作父类构造器的参数,必须声明为静态     private static final String DBNAME = "ljq.db";     private static final int VERSION = 1;     // 第三个参数CursorFactory指定在执行查询时获得一个游标实例的工厂类,     // 设置为null,代表使用系统默认的工厂类     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:生产环境上不能做删除操作         db.execSQL("DROP TABLE IF EXISTS PERSON");         onCreate(db);     } }
[b]PersonService业务类 [/b]
[u]复制代码[/u] 代码如下:
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;     /**      * 构造函数      *      * 调用getWritableDatabase()或getReadableDatabase()方法后,会缓存SQLiteDatabase实例;      * 因为这里是手机应用程序,一般只有一个用户访问数据库,所以建议不关闭数据库,保持连接状态。      * getWritableDatabase(),getReadableDatabase的区别是当数据库写满时,调用前者会报错,调用后者不会,      * 所以如果不是更新数据库的话,最好调用后者来获得数据库连接。      *      * 对于熟悉SQL语句的程序员最好使用exeSQL(),rawQuery(),因为比较直观明了      *      * @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;     }     /**      * 分页      *      * @param startResult 偏移量,默认从0开始      * @param maxResult 每页显示的条数      * @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;     }     }
[b]PersonServiceTest测试类 [/b]
[u]复制代码[/u] 代码如下:
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});     } }
[b]运行结果 [/b] [img]http://files.jb51.net/file_images/article/201304/201304271424223.png[/img]
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