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Android SQLite数据库增删改查操作的案例分析
摘要:Person实体类复制代码代码如下:packagecom.ljq.domain;publicclassPerson{privateInteg...

Person实体类

复制代码 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;

}

}

DBOpenHelper数据库关联类

复制代码 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);

}

}

PersonService业务类

复制代码 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;

}

}

PersonServiceTest测试类

复制代码 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});

}

}

运行结果

Android SQLite数据库增删改查操作的案例分析1

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