项目配置

• 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’

• 项目配置

注意，src-gen是我们新建一个文件夹，用来放GreenDao生成的文件

未完成该步骤之前，src-gen是空文件夹，我们需要新建一个包，在该包下新建一个Java文件，做初始化工作。
如图所示，我创建了名为’com.usst.chensl.introducdemo.db’的包，和名为’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 {
        //第一个参数是数据库版本号，第二个参数是所在包名
        Schema schema = new Schema(1, "com.usst.chensl.introductdemo.db");
        addDetail(schema);

        try {
            //第二个参数是我们前面新建的空文件夹sec-gen,这里采用相对路径的写法
            //‘..‘代表工程前一个目录,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。

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：

• 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~