项目配置
grdle配置
在Android Studio的build.gradle配上
compile 'de.greenrobot:greendao:1.3.7'
compile 'de.greenrobot:greendao-generator:1.3.1'生成代码
项目示例2
我们需要在包根目录新建一个Java文件，做初始化工作。
如图所示，包的根目录是'com.usst.chensl.greendaodemo'，创建一个名为'ExampleDaoGenerator'的Java文件。
ExampleDaoGenerator文件如下
package com.usst.chensl.introducdemo.db;
import de.greenrobot.daogenerator.DaoGenerator;
import de.greenrobot.daogenerator.Entity;
import de.greenrobot.daogenerator.Schema;
/**
* 初始化工作
* Created by ChenSL on 2015/8/14.
*/
public class ExampleDaoGenerator {
private static void addTaskDetail(Schema schema) {
//指定实体类
Entity entity = schema.addEntity("User");
//添加id属性
entity.addIdProperty();
//添加列userId,指定非空，默认可为空
entity.addStringProperty("userId").notNull();
//添加列username
entity.addStringProperty("username");
//添加列age
entity.addIntProperty("age");
//添加列phone
entity.addStringProperty("phone");
}
public static void main(String[] args) throws Exception {
//生成数据库文件的目标包名//target package for dao files
//第一个参数是数据库版本号，第二个参数是包的根目录的包
Schema schema = new Schema(1, "db");
addDetail(schema);
try {
//第二个参数是src-gen文件夹相对路径
//'..'代表工程前一个目录,接着是工程名/app(AndroidStudio生成)/
new DaoGenerator().generateAll(schema, "../GreenDaoDemo/app/src/main/java/com/usst/chensl/greendaodemo/");
} catch (Exception e) {
e.printStackTrace();
}
}
}
Entity可以看作是一张表,它使用构造器模式来设计，可以指定某一列的各种数据库属性，例如非空，自增，升降序，主键等。
同时，在工程目录下新建src-gen文件夹，放置代码生成的数据库文件。
项目文件结构目录
对着ExampleDaoGenerator右键，选择run ... main()，会在src-gen文件夹中生成四个文件。
注意：必须要使用run main()这种方法，在AndroidStudio下直接对该文件右键即可选择run main(),之前LZ试过在onCreate()里跑结果报错
下面来看看初始化出来的东西：
项目实例3
将db包拖动到包的根目录下，然后可以将src-gen文件夹下的东西全部删掉了。
初始化完成
初始化完成后，'ExampleDaoGenerator'就没用了，留着修改后可以创建另一个表，不需要可以删除。
-
user实体类，注释已经说明是GreenDao自动生成的。其实就跟自己建实体类一样，不过现在是代码自动生成
package com.usst.chensl.introductdemo.db; // THIS CODE IS GENERATED BY greenDAO, DO NOT EDIT. Enable "keep" sections if you want to edit. /** * Entity mapped to table USER. */ public class User { private Long id; private String userId; private String username; private String age; private String phone; public User() { } public User(Long id) { this.id = id; } public User(Long id, String userId, String username, String age, String phone) { this.id = id; this.userId = userId; this.username = username; this.age = age; this.phone = phone; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getUserId() { return userId; } public void setUserId(String userId) { this.userId = userId; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getAge() { return age; } public void setAge(String age) { this.age = age; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } } -
userDao，如果自己实现过简单的ORM框架的话，很容易就看出这个是对sql语句的包装，有
createTable（），dropTable,readEntity,updateKeyAfterInsert,这些望文生义的方法package com.usst.chensl.introductdemo.db; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteStatement; import de.greenrobot.dao.AbstractDao; import de.greenrobot.dao.Property; import de.greenrobot.dao.internal.DaoConfig; import com.usst.chensl.introductdemo.db.User; // THIS CODE IS GENERATED BY greenDAO, DO NOT EDIT. /** * DAO for table USER. */ 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 { //参数分别是(列数，类型，Java实体类的变量名，是否主键，数据库列名) //因为上面有entity.addIdProperty()，所以自动生成了主键'_id' 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, "USERNAME"); public final static Property Age = new Property(3, String.class, "age", false, "AGE"); public final static Property Phone = new Property(4, String.class, "phone", false, "PHONE"); }; public UserDao(DaoConfig config) { super(config); } public UserDao(DaoConfig config, DaoSession daoSession) { super(config, daoSession); } /** Creates the underlying database table. */ public static void createTable(SQLiteDatabase db, boolean ifNotExists) { String constraint = ifNotExists? "IF NOT EXISTS ": ""; db.execSQL("CREATE TABLE " + constraint + "'USER' (" + // "'_id' INTEGER PRIMARY KEY ," + // 0: id "'USER_ID' TEXT," + // 1: userId "'USERNAME' TEXT," + // 2: username "'AGE' TEXT," + // 3: age "'PHONE' TEXT);"); // 4: phone } /** Drops the underlying database table. */ public static void dropTable(SQLiteDatabase db, boolean ifExists) { String sql = "DROP TABLE " + (ifExists ? "IF EXISTS " : "") + "'USER'"; db.execSQL(sql); } /** @inheritdoc */ @Override protected 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); } String age = entity.getAge(); if (age != null) { stmt.bindString(4, age); } String phone = entity.getPhone(); if (phone != null) { stmt.bindString(5, phone); } } /** @inheritdoc */ @Override public Long readKey(Cursor cursor, int offset) { return cursor.isNull(offset + 0) ? null : cursor.getLong(offset + 0); } /** @inheritdoc */ @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.isNull(offset + 3) ? null : cursor.getString(offset + 3), // age cursor.isNull(offset + 4) ? null : cursor.getString(offset + 4) // phone ); return entity; } /** @inheritdoc */ @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.isNull(offset + 3) ? null : cursor.getString(offset + 3)); entity.setPhone(cursor.isNull(offset + 4) ? null : cursor.getString(offset + 4)); } /** @inheritdoc */ @Override protected Long updateKeyAfterInsert(User entity, long rowId) { entity.setId(rowId); return rowId; } /** @inheritdoc */ @Override public Long getKey(User entity) { if(entity != null) { return entity.getId(); } else { return null; } } /** @inheritdoc */ @Override protected boolean isEntityUpdateable() { return true; } } -
DaoSession,数据库Session
package com.usst.chensl.introductdemo.db; import android.database.sqlite.SQLiteDatabase; import java.util.Map; import de.greenrobot.dao.AbstractDao; import de.greenrobot.dao.AbstractDaoSession; import de.greenrobot.dao.identityscope.IdentityScopeType; import de.greenrobot.dao.internal.DaoConfig; import com.usst.chensl.introductdemo.db.User; import com.usst.chensl.introductdemo.db.UserDao; // THIS CODE IS GENERATED BY greenDAO, DO NOT EDIT. /** * {@inheritDoc} * * @see de.greenrobot.dao.AbstractDaoSession */ public class DaoSession extends AbstractDaoSession { private final DaoConfig userDaoConfig; private final UserDao userDao; public DaoSession(SQLiteDatabase 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.getIdentityScope().clear(); } public UserDao getUserDao() { return userDao; } } -
DaoMaster,对
SQLiteDatabase的封装,包含了UserDaopackage com.usst.chensl.introductdemo.db; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; import android.util.Log; import de.greenrobot.dao.AbstractDaoMaster; import de.greenrobot.dao.identityscope.IdentityScopeType; import com.usst.chensl.introductdemo.db.UserDao; // THIS CODE IS GENERATED BY greenDAO, DO NOT EDIT. /** * Master of DAO (schema version 1): knows all DAOs. */ public class DaoMaster extends AbstractDaoMaster { public static final int SCHEMA_VERSION = 1; /** Creates underlying database table using DAOs. */ public static void createAllTables(SQLiteDatabase db, boolean ifNotExists) { UserDao.createTable(db, ifNotExists); } /** Drops underlying database table using DAOs. */ public static void dropAllTables(SQLiteDatabase db, boolean ifExists) { UserDao.dropTable(db, ifExists); } //抽象类 public static abstract class OpenHelper extends SQLiteOpenHelper { public OpenHelper(Context context, String name, CursorFactory factory) { super(context, name, factory, SCHEMA_VERSION); } @Override public void onCreate(SQLiteDatabase db) { Log.i("greenDAO", "Creating tables for schema version " + SCHEMA_VERSION); createAllTables(db, false); } } //真正实现类 /** WARNING: Drops all table on Upgrade! Use only during development. */ public static class DevOpenHelper extends OpenHelper { public DevOpenHelper(Context context, String name, CursorFactory factory) { super(context, name, factory); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { Log.i("greenDAO", "Upgrading schema from version " + oldVersion + " to " + newVersion + " by dropping all tables"); dropAllTables(db, true); onCreate(db); } } public DaoMaster(SQLiteDatabase 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); } }
DbMaster的最终目的是获取DbSession,通过DbSession对数据库进行操作。
下一篇说GreenDao具体使用，敬请期待~
