項目配置

grdle配置

在Android Studio的gradle配上

compile ‘de.greenrobot:greendao:1.3.7’
compile ‘de.greenrobot:greendao-generator:1.3.1’
項目配置

注意，src-gen是我們新建一個文件夾，用來放GreenDao生成的文件

未完成該步驟之前，src-gen是空文件夾，我們需要新建一個包，在該包下新建一個Java文件，做初始化工作。
如圖所示，我創建了名爲’com.usst.chensl.introducdemo.db’的包，和名爲’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) {
        //指定實體類
        Entity entity = schema.addEntity("User");
        //添加id屬性
        entity.addIdProperty();
        //添加列userId,指定非空，默認可爲空
        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 {
        //第一個參數是數據庫版本號，第二個參數是所在包名
        Schema schema = new Schema(1, "com.usst.chensl.introductdemo.db");
        addDetail(schema);

        try {
            //第二個參數是我們前面新建的空文件夾sec-gen,這裏採用相對路徑的寫法
            //'..'代表工程前一個目錄,接着是工程名/app(AndroidStudio生成)/src-gen(自己建的)
            new DaoGenerator().generateAll(schema, "../IntroducDemo/app/src-gen");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Entity可以看作是一張表,它使用構造器模式來設計，可以指定某一列的各種數據庫屬性，例如非空，自增，升降序，主鍵等。

注意：必須要使用run main()這種方法，在AndroidStudio下直接對該文件右鍵即可選擇run main(),之前LZ試過在onCreate()裏跑結果報錯

下面來看看初始化出來的東西：

user實體類，註釋已經說明是GreenDao自動生成的。其實就跟自己建實體類一樣，不過現在是代碼自動生成

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，如果自己實現過簡單的ORM框架的話，很容易就看出這個是對sql語句的包裝，有createTable（），dropTable,readEntity,updateKeyAfterInsert,這些望文生義的方法

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 {
        //參數分別是(列數，類型，Java實體類的變量名，是否主鍵，數據庫列名)
        //因爲上面有entity.addIdProperty()，所以自動生成了主鍵'_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,數據庫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,對SQLiteDatabase的封裝,包含了UserDao

package 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);
    }

    //抽象類
    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);
        }
    }

    //真正實現類
    /** 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的最終目的是獲取DbSession,通過DbSession對數據庫進行操作。

下一篇說GreenDao具體使用，敬請期待~

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