Android ORM
2017-08-01 本文已影响0人
Jamling
简介
您是否在Android上使用sqlite来存储您的应用数据呢？如果是，或许您会对Android存取sqlite数据感觉有点小复杂。本人从2010年开始从事Android开发，对于Android的数据库操纵这一块，感觉还是比较复杂的，尤其是可维护性及或可扩展性方面，都是比较差的。
也正是从这时开始，我决定在Android平台上实现像Hibernate那样的ORM框架，来简化开发工作。使得开发者在使用sqlite数据库时，无需关注底层数据库实现，更多的是关注上层业务逻辑实现。
如果您对此项目感兴趣，欢迎您的加入！
特性
- 简洁的ORM映射配置, 只需在Java Bean的属性中添加类似
@Column(name="_name")的注解即可完成到数据库字段的映射配置. - 强大的正向工程支持, 自动生成DDL和ContentProvider.
- 给力的辅助工具, 向导式新建Activity/Service/BroadcastReceiver并且自动配置到AndroidManifest.xml.
- ...
更多特性，请自行体验.
使用
latest release, 在使用中请将$latest替换为具体的版本.
Eclipse
下载aorm-core-$latest.jar并放入libs/目录下
推荐安装Android ADT-extensions插件
Android Studio
Aorm已经发布到jcenter，在您的app/build.gradle中添加以下依赖。
dependencies {
compile 'cn.ieclipse.aorm:aorm-core:1.1.5'
}
推荐安装Android Studio上的Android ORM Tool插件，可以快速生成相关代码。
类似orm库比较
简单试验结果:
Simple Trial
复杂试验结果:
Complex Trial
测试工程代码请参考: https://github.com/Raizlabs/AndroidDatabaseLibraryComparison
示例代码
创建映射
只需添加类@Table注解及@Column属性注解即可完成表与字段的映射。
@Table(name = "student")
public class Student implements Serializable {
@Column(name = "_id", id = true)
public long id; //id is Primary key.
@Column(name="_name")
public String name; //mapping to _name and auto column type
@Column()
public int age; //auto column type and name
@Column(defaultValue="''")
public String phone; // default value in empty
public String address; // no mapping
}
Create database
package cn.ieclipse.aorm.example;
import android.content.ContentProvider;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.net.Uri;
import cn.ieclipse.aorm.Aorm;
import cn.ieclipse.aorm.Session;
import cn.ieclipse.aorm.example.bean.Course;
import cn.ieclipse.aorm.example.bean.Grade;
import cn.ieclipse.aorm.example.bean.Student;
/**
* @author Jamling
*
*/
public class ExampleContentProvider extends ContentProvider {
public static final String AUTH = "cn.ieclipse.aorm.example.provider";
public static final Uri URI = Uri.parse("content://" + AUTH);
private SQLiteOpenHelper mOpenHelper;
private static Session session;
@Override
public int delete(Uri arg0, String arg1, String[] arg2) {
return 0;
}
@Override
public String getType(Uri arg0) {
return null;
}
@Override
public Uri insert(Uri arg0, ContentValues arg1) {
return null;
}
@Override
public Cursor query(Uri arg0, String[] arg1, String arg2, String[] arg3,
String arg4) {
return null;
}
@Override
public int update(Uri arg0, ContentValues arg1, String arg2, String[] arg3) {
return 0;
}
public static Session getSession() {
return session;
}
@Override
public boolean onCreate() {
mOpenHelper = new SQLiteOpenHelper(this.getContext(), "example.db",
null, 1) {
public void onCreate(SQLiteDatabase db) {
// method 3: use AORM to create table
Aorm.createTable(db, Grade.class);
Aorm.createTable(db, Student.class);
Aorm.createTable(db, Course.class);
}
public void onUpgrade(SQLiteDatabase db, int oldVersion,
int newVersion) {
// update table, suggested to wrapper in if block
Aorm.updateTable(db, Grade.class);
Aorm.updateTable(db, Student.class);
Aorm.updateTable(db, Course.class);
}
};
session = new Session(mOpenHelper, getContext().getContentResolver());
return true;
}
}
查询
Session session = ExampleContentProvider.getSession();
// 最简单的查询：查询所有的学生信息.
Criteria criteria = Criteria.create(Student.class);
// 添加条件: id相等
criteria.add(Restrictions.eq("id", 1));
// 添加条件: name like Jamling
criteria.add(Restrictions.like("name", "Jaming"));
// add restriction: age < 30
criteria.add(Restrictions.lt("age", 30));
// add order
criteria.addOrder(Order.asc("age"));
// set district
criteria.setDistinct(true);
// set limit from row 10 to 20
criteria.setLimit(10, 10);
List<Student> list = session.list(Student.class);
// if you use Android CursorAdapter you can:
Cursor c = session.query(criteria);
// set alias, so the project will be alias.columnn. e.g. s.name
// criteria.setAlias("s");
// multi-table query
criteria.addChild(StudentMore.class, "m", Criteria.INNER_JOIN,
Restrictions.geProperty("s.id", "m.id"));
// query to cursor
c = session.query(criteria);
// convert to list.
List<Object[]> ret = CursorUtils.getFromCursor(c,
new Class[] { Student.class }, new String[] { "s", "m" });
// query to list.
ret = session.listAll(criteria);
Object[] item = ret.get(0);
Student s = (Student) item[0];
StudentMore m = (StudentMore) item[1];
//
其它操作
Session session = ExampleContentProvider.getSession();
// insert
Student s = new Student();
s.setName("Jamling");
long rowId = session.insert(s, null);
// update student's name to Jame whose id is 1
s.setId(1);
s.setName("Jame");
int rows = session.update(s);
// delete student whose id is 2
session.deleteById(Student.class, 2);
// query student whose id is 4
s = session.get(Student.class, 4);
