zoukankan      html  css  js  c++  java

  • [转]Android ORM系列之GreenDao最佳实践

    GreenDAO是一个可以帮助Android开发者快速将Java对象映射到SQLite数据库的表单中的ORM解决方案，通过使用一个简单的面向对象API，开发者可以对Java对象进行存储、更新、删除和查询。

    GreenDao有两个项目，一个是生成dao和model的generator的项目，该项目是java项目，一个是用于android的核心jar包。在使用前，我们必须先生成dao和model。

    首先加入依赖。

    compile 'de.greenrobot:greendao:2.0.0'
compile 'de.greenrobot:greendao-generator:2.0.0'

    然后在我们的包名之下新建一个db的包，在db下新建dao和model的包以及一个generator的包，就像下图。
    这里写图片描述

    在generator包下，新建一个生成dao和model的类GreenDaoGenerator，在里面加入代码

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    public class GreenDaoGenerator {
        public static void main(String[] args) throws Exception {
            Schema schema = new Schema(1, "cn.edu.zafu.greendao.db.model");
            schema.setDefaultJavaPackageDao("cn.edu.zafu.greendao.db.dao");
            schema.enableKeepSectionsByDefault();
            //schema.enableActiveEntitiesByDefault();
            //ActiveRecord
            addEntity(schema);
            new DaoGenerator().generateAll(schema, "./app/src/main/java");
        }
     
        private static void addEntity(Schema schema) {
            Entity person = schema.addEntity("Person");
            person.addIdProperty().primaryKey();
            person.addStringProperty("name");
            person.addDoubleProperty("height");
            person.addDoubleProperty("weight");
     
            Entity card = schema.addEntity("Card");
            card.addIdProperty().primaryKey();
            card.addStringProperty("num");
            card.addStringProperty("address");
     
            Property idcardPK = person.addLongProperty("cardId").getProperty();
            person.addToOne(card, idcardPK);
     
            Property personPK = card.addLongProperty("personId").getProperty();
            card.addToOne(person,personPK);
        }
     
    }

    Schema schema = new Schema(1, “cn.edu.zafu.greendao.db.model”); 代表创建的数据库的版本号以及默认的java package，如果不修改默认的包名，生成的dao和model都会在该包下，这里我们修改了dao的包名schema.setDefaultJavaPackageDao(“cn.edu.zafu.greendao.db.dao”);，生成的model中，我们可能需要加入自己的一些信息，但是又不希望下次生成的时候消失，所以可以使用schema.enableKeepSectionsByDefault();，使用后会在model类中有如下这些标示

    1
    2
    3
    4
    5
    6
    7
    8
    // KEEP INCLUDES - put your custom includes here
    // KEEP INCLUDES END
     
    // KEEP FIELDS - put your custom fields here
    // KEEP FIELDS END
     
     // KEEP METHODS - put your custom methods here
    // KEEP METHODS END

    你只需将你需要的信息添加到这三个之间，分布代表引入的包，字段，方法。之后重新生成这些信息将会被保留。

    schema.enableActiveEntitiesByDefault();代表实体类是否支持active，用过php中yii框架的都应该清楚，实体类可以直接进行crud操作。我们不开启就好了，如果开启了的话，实体类将之间支持update, refresh, deleted 等操作。

    之后就使用 schema.addEntity()函数增加Entity 对象，即对应的实体类，通过添加属性方法addProperty系列方法增加字段，最后调用new DaoGenerator().generateAll(schema, “./app/src/main/java”);方法生成dao和model。

    生成的步骤也很简单，在该类上右键，点run即可。

    这里写图片描述

    生成之后控制台就会输出

    这里写图片描述

    然后我们编写一个核心辅助类。用于获取DaoMaster和DaoSession

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    public class DbCore {
        private static final String DEFAULT_DB_NAME = "default.db";
        private static DaoMaster daoMaster;
        private static DaoSession daoSession;
     
        private static Context mContext;
        private static String DB_NAME;
     
        public static void init(Context context) {
            init(context, DEFAULT_DB_NAME);
        }
     
        public static void init(Context context, String dbName) {
            if (context == null) {
                throw new IllegalArgumentException("context can't be null");
            }
            mContext = context.getApplicationContext();
            DB_NAME = dbName;
        }
     
        public static DaoMaster getDaoMaster() {
            if (daoMaster == null) {
                DaoMaster.OpenHelper helper = new DaoMaster.DevOpenHelper(mContext, DB_NAME, null);
                daoMaster = new DaoMaster(helper.getWritableDatabase());
            }
            return daoMaster;
        }
     
        public static DaoSession getDaoSession() {
            if (daoSession == null) {
                if (daoMaster == null) {
                    daoMaster = getDaoMaster();
                }
                daoSession = daoMaster.newSession();
            }
            return daoSession;
        }
     
        public static void enableQueryBuilderLog(){
     
            QueryBuilder.LOG_SQL = true;
            QueryBuilder.LOG_VALUES = true;
        }
    }

    接下来就是基础的泛型Service

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    public class BaseService<T, K> {
        private AbstractDao<T, K> mDao;
     
        public BaseService(AbstractDao dao) {
            mDao = dao;
        }
     
        public void save(T item) {
            mDao.insert(item);
        }
     
        public void save(T... items) {
            mDao.insertInTx(items);
        }
     
        public void save(List<T> items) {
            mDao.insertInTx(items);
        }
     
        public void saveOrUpdate(T item) {
            mDao.insertOrReplace(item);
        }
     
        public void saveOrUpdate(T... items) {
            mDao.insertOrReplaceInTx(items);
        }
     
        public void saveOrUpdate(List<T> items) {
            mDao.insertOrReplaceInTx(items);
        }
     
        public void deleteByKey(K key) {
            mDao.deleteByKey(key);
        }
     
        public void delete(T item) {
            mDao.delete(item);
        }
     
        public void delete(T... items) {
            mDao.deleteInTx(items);
        }
     
        public void delete(List<T> items) {
            mDao.deleteInTx(items);
        }
     
        public void deleteAll() {
            mDao.deleteAll();
        }
     
        public void update(T item) {
            mDao.update(item);
        }
     
        public void update(T... items) {
            mDao.updateInTx(items);
        }
     
        public void update(List<T> items) {
            mDao.updateInTx(items);
        }
     
        public  T query(K key) {
            return  mDao.load(key);
        }
     
        public List<T> queryAll() {
            return mDao.loadAll();
        }
     
        public List<T> query(String where, String... params) {
     
            return mDao.queryRaw(where, params);
        }
     
        public QueryBuilder<T> queryBuilder() {
     
            return mDao.queryBuilder();
        }
     
        public long count() {
            return mDao.count();
        }
     
        public void refresh(T item) {
            mDao.refresh(item);
     
        }
     
        public void detach(T item) {
            mDao.detach(item);
        }
    }

    一个实现类，第二个泛型参数是主键类型

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    public class CardService extends BaseService<Card,Long> {
        public CardService(CardDao dao) {
            super(dao);
        }
    }
    public class PersonService extends BaseService<Person,Long> {
        public PersonService(PersonDao dao) {
            super(dao);
        }
    }

    编写一个工具类获得service

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    public class DbUtil {
        private static CardService cardService;
        private static PersonService personService;
     
        private static PersonDao getPersonDao() {
            return DbCore.getDaoSession().getPersonDao();
        }
     
        private static CardDao getCardDao() {
            return DbCore.getDaoSession().getCardDao();
        }
     
        public static CardService getCardService() {
            if (cardService == null) {
                cardService = new CardService(getCardDao());
            }
            return cardService;
        }
     
        public static PersonService getPersonService() {
            if (personService == null) {
                personService = new PersonService(getPersonDao());
            }
            return personService;
        }
    }

    在Application中初始化，并设置在清单文件中

    1
    2
    3
    4
    5
    6
    7
    public class App extends Application{
        @Override
        public void onCreate() {
            super.onCreate();
            DbCore.init(this);
        }
    }

    增删改查，下面为单元测试的方法

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    95
    96
    97
    98
    99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    165
    166
    167
    168
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194
    195
    196
    public class ApplicationTest extends ApplicationTestCase<Application> {
        private PersonService mPersonService;
        private CardService mCardService;
     
        public ApplicationTest() {
            super(Application.class);
        }
     
        @Override
        protected void setUp() throws Exception {
            super.setUp();
            DbCore.init(getContext());
            DbCore.enableQueryBuilderLog();
            mPersonService = DbUtil.getPersonService();
            mCardService = DbUtil.getCardService();
        }
     
        public void testSave(){
            Card c=new Card();
            c.setNum("3303241646813416463468");
            c.setAddress("杭州");
     
            mCardService.save(c);
     
            Person p=new Person();
            p.setName("张三");
            p.setHeight(178.00);
            p.setWeight(65.00);
            p.setCard(c);
            mPersonService.save(p);
     
            c.setPerson(p);
            mCardService.saveOrUpdate(c);
     
        }
        public void testSave1(){
            Card c=new Card();
            c.setNum("3303241646813416463468");
            c.setAddress("杭州");
     
            Card c1=new Card();
            c1.setNum("12121646813416463468");
            c1.setAddress("温州");
     
            mCardService.save(c, c1);
     
            c.setNum("11111");
            mCardService.saveOrUpdate(c, c1);
     
        }
     
        public void testSave2(){
            Card c=new Card();
            c.setNum("3303241646813416463468");
            c.setAddress("杭州");
     
            Card c1=new Card();
            c1.setNum("12121646813416463468");
            c1.setAddress("温州");
     
            List&lt;Card&gt; cards=new ArrayList&lt;Card&gt;();
     
            cards.add(c);
            cards.add(c1);
     
            mCardService.save(cards);
     
            c1.setNum("22222");
     
            mCardService.saveOrUpdate(cards);
     
        }
     
        public void testDelete(){
            Card c=new Card();
            c.setNum("333333333333333");
            c.setAddress("3333");
     
            mCardService.save(c);
            mCardService.delete(c);
     
            c=new Card();
            c.setNum("444444");
            c.setAddress("44444444");
     
            mCardService.save(c);
            mCardService.deleteByKey(c.getId());
     
        }
     
        public void testDelete1(){
            Card c=new Card();
            c.setNum("55555");
            c.setAddress("5555");
     
            Card c1=new Card();
            c1.setNum("666666");
            c1.setAddress("66666666");
            mCardService.save(c,c1);
            mCardService.delete(c, c1);
     
        }
     
        public void testDelete2(){
            Card c=new Card();
            c.setNum("55555");
            c.setAddress("5555");
     
            Card c1=new Card();
            c1.setNum("666666");
            c1.setAddress("66666666");
            List&lt;Card&gt; cards=new ArrayList&lt;Card&gt;();
     
            cards.add(c);
            cards.add(c1);
     
            mCardService.save(cards);
            mCardService.delete(cards);
     
        }
     
        public  void testDelete3(){
            mCardService.deleteAll();
        }
     
        public void testUpdate(){
            Card c=new Card();
            c.setNum("55555");
            c.setAddress("5555");
     
            mCardService.save(c);
            c.setNum("123456");
            mCardService.update(c);
        }
        public void testUpdate1(){
            Card c=new Card();
            c.setNum("55555");
            c.setAddress("5555");
     
            mCardService.save(c);
            c.setNum("123456");
     
            Card c1=new Card();
            c1.setNum("6666");
            c1.setAddress("66666");
     
            mCardService.save(c1);
            c1.setNum("654321");
            mCardService.update(c,c1);
        }
     
        public void testUpdate2(){
            Card c=new Card();
            c.setNum("aaaaa");
            c.setAddress("aaaaaaaaaa");
     
            mCardService.save(c);
            c.setNum("bbbbbbbbb");
     
            Card c1=new Card();
            c1.setNum("ccccc");
            c1.setAddress("cccccccc");
     
            mCardService.save(c1);
            c1.setNum("dddddddddd");
     
            List<Card> cards=new ArrayList<Card>();
     
            cards.add(c);
            cards.add(c1);
            mCardService.update(cards);
        }
     
        public void testQuery(){
            Card c=new Card();
            c.setNum("aaaaa111");
            c.setAddress("aaaaaaaa11111aa");
     
            mCardService.save(c);
     
            List&lt;Card&gt; cards = mCardService.queryAll();
            Log.e("TAG", cards + "");
     
            Card query = mCardService.query(c.getId());
            Log.e("TAG", query + "");
     
            List&lt;Card&gt; query1 = mCardService.query("where NUM=?", c.getNum());
            Log.e("TAG", query1 + "");
     
            long count = mCardService.count();
            Log.e("TAG", count + "");
     
            List&lt;Card&gt; list = mCardService.queryBuilder().where(CardDao.Properties.Num.eq(c.getNum())).list();
            Log.e("TAG", list + "");
        }
    }

    关于关联关系的映射，下一篇文章细说。

    源码下载。
  • 相关阅读:
    2020软件工程第一次个人编程作业
    2020软件工程第一次作业
    软件实践个人总结
    2020软件工程第四次编程作业-实验家族树
    2020软件工程个人编程作业
    软工实践个人总结
    2020软件工程结对编程之实验室程序实现
    2020软件工程第一次个人编程作业
    软工作业
    机器学习第四章笔记
  • 原文地址：https://www.cnblogs.com/qianyukun/p/5196545.html
Copyright © 2011-2022 走看看