第三方开源库--＞ GreenDao 数据库
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简介
目前最新版本是 3.3.0。
GitHub：greenDAO
特点
- 最佳性能 (可能是 android 中最快的 ORM) ，基准测试也是开源的；
- 易于使用的功能强大的 api，涵盖关系和连接；
- 最小的内存消耗；
- 小型库大小(< 100KB) ，以保持较低的构建时间，并避免65k 方法限制；
- 数据库加密：greenDAO 支持 SQLCipher 来保证用户数据的安全；
- 强大而活跃的社区交流支持。
基本配置
- 在项目目录下 build.gradle 添加依赖：
buildscript
repositories
google()
mavenCentral()
dependencies
classpath "com.android.tools.build:gradle:4.2.1"
classpath 'org.greenrobot:greendao-gradle-plugin:3.3.0'
- 在 app目录下 build.gradle 添加依赖：
plugins
id 'com.android.application'
id 'org.greenrobot.greendao'
--------------------------------------
// greendao
implementation 'org.greenrobot:greendao:3.3.0'
// RecyclerAdapter
implementation 'com.github.CymChad:BaseRecyclerViewAdapterHelper:2.9.30'
----------------------------------------------
greendao
schemaVersion 1 //当前数据库版本
核心类
1. DaoMaster.java
/**
* Created on 2021/7/14 13:56
*
* @author Gong Youqiang
*/
public class DaoMaster extends AbstractDaoMaster
public static final int SCHEMA_VERSION = 1;
/** Creates underlying database table using DAOs. */
public static void createAllTables(Database db, boolean ifNotExists)
UserDao.createTable(db, ifNotExists);
/** Drops underlying database table using DAOs. */
public static void dropAllTables(Database db, boolean ifExists)
UserDao.dropTable(db, ifExists);
/**
* WARNING: Drops all table on Upgrade! Use only during development.
* Convenience method using a @link DevOpenHelper.
*/
public static DaoSession newDevSession(Context context, String name)
Database db = new DevOpenHelper(context, name).getWritableDb();
DaoMaster daoMaster = new DaoMaster(db);
return daoMaster.newSession();
public DaoMaster(SQLiteDatabase db)
this(new StandardDatabase(db));
public DaoMaster(Database db)
super(db, SCHEMA_VERSION);
registerDaoClass(UserDao.class);
public DaoSession newSession()
return new DaoSession(db, IdentityScopeType.Session, daoConfigMap);
public DaoSession newSession(IdentityScopeType type)
return new DaoSession(db, type, daoConfigMap);
/**
* Calls @link #createAllTables(Database, boolean) in @link #onCreate(Database) -
*/
public static abstract class OpenHelper extends DatabaseOpenHelper
public OpenHelper(Context context, String name)
super(context, name, SCHEMA_VERSION);
public OpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory)
super(context, name, factory, SCHEMA_VERSION);
@Override
public void onCreate(Database db)
Log.i("greenDAO", "Creating tables for schema version " + SCHEMA_VERSION);
createAllTables(db, false);
/** WARNING: Drops all table on Upgrade! Use only during development. */
public static class DevOpenHelper extends OpenHelper
public DevOpenHelper(Context context, String name)
super(context, name);
public DevOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory)
super(context, name, factory);
@Override
public void onUpgrade(Database db, int oldVersion, int newVersion)
Log.i("greenDAO", "Upgrading schema from version " + oldVersion + " to " + newVersion + " by dropping all tables");
dropAllTables(db, true);
onCreate(db);
- DaoSession.java
/**
* Created on 2021/7/14 13:58
*
* @author Gong Youqiang
*/
public class DaoSession extends AbstractDaoSession
private final DaoConfig userDaoConfig;
private final UserDao userDao;
public DaoSession(Database db, IdentityScopeType type, Map<Class<? extends AbstractDao<?, ?>>, DaoConfig>
daoConfigMap)
super(db);
userDaoConfig = daoConfigMap.get(UserDao.class).clone();
userDaoConfig.initIdentityScope(type);
userDao = new UserDao(userDaoConfig, this);
registerDao(User.class, userDao);
public void clear()
userDaoConfig.clearIdentityScope();
public UserDao getUserDao()
return userDao;
- UserDao.java
/**
* Created on 2021/7/14 13:58
*
* @author Gong Youqiang
*/
public class UserDao extends AbstractDao<User, Long>
public static final String TABLENAME = "USER";
/**
* Properties of entity User.<br/>
* Can be used for QueryBuilder and for referencing column names.
*/
public static class Properties
public final static Property Id = new Property(0, Long.class, "id", true, "_id");
public final static Property UserId = new Property(1, String.class, "userId", false, "USER_ID");
public final static Property UserName = new Property(2, String.class, "userName", false, "USER_NAME");
public final static Property Age = new Property(3, int.class, "age", false, "AGE");
public UserDao(DaoConfig config)
super(config);
public UserDao(DaoConfig config, DaoSession daoSession)
super(config, daoSession);
/** Creates the underlying database table. */
public static void createTable(Database db, boolean ifNotExists)
String constraint = ifNotExists? "IF NOT EXISTS ": "";
db.execSQL("CREATE TABLE " + constraint + "\\"USER\\" (" + //
"\\"_id\\" INTEGER PRIMARY KEY AUTOINCREMENT ," + // 0: id
"\\"USER_ID\\" TEXT UNIQUE ," + // 1: userId
"\\"USER_NAME\\" TEXT," + // 2: userName
"\\"AGE\\" INTEGER NOT NULL );"); // 3: age
/** Drops the underlying database table. */
public static void dropTable(Database db, boolean ifExists)
String sql = "DROP TABLE " + (ifExists ? "IF EXISTS " : "") + "\\"USER\\"";
db.execSQL(sql);
@Override
protected final void bindValues(DatabaseStatement stmt, User entity)
stmt.clearBindings();
Long id = entity.getId();
if (id != null)
stmt.bindLong(1, id);
String userId = entity.getUserId();
if (userId != null)
stmt.bindString(2, userId);
String userName = entity.getUserName();
if (userName != null)
stmt.bindString(3, userName);
stmt.bindLong(4, entity.getAge());
@Override
protected final void bindValues(SQLiteStatement stmt, User entity)
stmt.clearBindings();
Long id = entity.getId();
if (id != null)
stmt.bindLong(1, id);
String userId = entity.getUserId();
if (userId != null)
stmt.bindString(2, userId);
String userName = entity.getUserName();
if (userName != null)
stmt.bindString(3, userName);
stmt.bindLong(4, entity.getAge());
@Override
public Long readKey(Cursor cursor, int offset)
return cursor.isNull(offset + 0) ? null : cursor.getLong(offset + 0);
@Override
public User readEntity(Cursor cursor, int offset)
User entity = new User( //
cursor.isNull(offset + 0) ? null : cursor.getLong(offset + 0), // id
cursor.isNull(offset + 1) ? null : cursor.getString(offset + 1), // userId
cursor.isNull(offset + 2) ? null : cursor.getString(offset + 2), // userName
cursor.getInt(offset + 3) // age
);
return entity;
@Override
public void readEntity(Cursor cursor, User entity, int offset)
entity.setId(cursor.isNull(offset + 0) ? null : cursor.getLong(offset + 0));
entity.setUserId(cursor.isNull(offset + 1) ? null : cursor.getString(offset + 1));
entity.setUserName(cursor.isNull(offset + 2) ? null : cursor.getString(offset + 2));
entity.setAge(cursor.getInt(offset + 3));
@Override
protected final Long updateKeyAfterInsert(User entity, long rowId)
entity.setId(rowId);
return rowId;
@Override
public Long getKey(User entity)
if(entity != null)
return entity.getId();
else
return null;
@Override
public boolean hasKey(User entity)
return entity.getId() != null;
@Override
protected final boolean isEntityUpdateable()
return true;
- 实体类
/**
* Created on 2021/7/14 13:53
*
* @author Gong Youqiang
*/
@Entity
public class User
@Id(autoincrement = true)
private Long id;
@Unique
private String userId;
@Property
private String userName;
@Property
private int age;
@Generated(hash = 1975221261)
public User(Long id, String userId, String userName, int age)
this.id = id;
this.userId = userId;
this.userName = userName;
this.age = age;
@Generated(hash = 586692638)
public User()
public Long getId()
return this.id;
public void setId(Long id)
this.id = id;
public String getUserId()
return this.userId;
public void setUserId(String userId)
this.userId = userId;
public String getUserName()
return this.userName;
public void setUserName(String userName)
this.userName = userName;
public int getAge()
return this.age;
public void setAge(int age)
this.age = age;
Demo
效果图
代码
- DaoManager.java
/**
* Created on 2021/7/14 13:55
* 创建数据库、创建数据库表、包含增删改查的操作
* @author Gong Youqiang
*/
public class DaoManager
private static final String TAG = DaoManager.class.getSimpleName();
private static final String DB_NAME = "RECORD_DB";
private Application mApplication;
//多线程中要被共享的使用volatile关键字修饰
private volatile static DaoManager manager = new DaoManager();
private DaoMaster mDaoMaster;
private DaoMaster.DevOpenHelper mHelper;
private DaoSession mDaoSession;
/**
* 单例模式获得操作数据库对象
*/
public static DaoManager getInstance()
return manager;
private DaoManager()
setDebug();
public void init(Application application)
this.mApplication = application;
/**
* 判断是否有存在数据库，如果没有则创建
*/
public DaoMaster getDaoMaster()
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