GreenDao数据库的使用

创建Android测试项目，导入相关资源

    sourceSets {        main {            java.srcDirs = ['src/main/java', 'src/main/java-gen']        }    }    compile 'de.greenrobot:greendao-generator:2.1.0'    compile 'de.greenrobot:greendao:2.1.0'

在Android项目下创建用于生成帮助类及Bean的java文件

• 创建java文件
  

  

  

  

• 编写具体的ExampleDaoGenerator代码如下：

  import de.greenrobot.daogenerator.DaoGenerator;import de.greenrobot.daogenerator.Entity;import de.greenrobot.daogenerator.Schema;public class ExampleDaoGenerator {    private static void addTaskDetail(Schema schema) {        //指定实体类，参数是实体类的类名        Entity entity = schema.addEntity("User");        //添加id索引        entity.addIdProperty();        //添加属性userId,指定非空        entity.addStringProperty("userId").notNull();        //添加属性username        entity.addStringProperty("username");        //添加属性age        entity.addIntProperty("age");        //添加属性phone        entity.addStringProperty("phone");        Entity entity1 = schema.addEntity("Person");        entity1.addIdProperty();        entity1.addStringProperty("personId").notNull();        entity1.addStringProperty("personName");    }    //生成数据库文件的目标包名//target package for dao files    public static void main(String[] args) throws Exception {        // 第一个参数是数据库版本号，第二个参数是生成的文件所处的路径        Schema schema = new Schema(1, "com.lpf.greendb.db.bean");        // 此行代码不加，所有生成的文件将会在同一个目录下，加了此行代码，帮助类将会生成在次路径下        schema.setDefaultJavaPackageDao("com.lpf.greendb.db.helper");        addTaskDetail(schema);        try {            //'..'代表当前目录,接着就是个人的项目路径            new DaoGenerator().generateAll(schema, "../greenDB/app/src/main/java/");        } catch (Exception e) {            e.printStackTrace();        }    }}

• 右键ExampleDaoGenerator文件，run ExampleDaoGenerator.main(),自动生成代码
  

  

操作数据库

• 创建MyApplication对象

  初始化DaoMaster和DaoSession

      public class MyApplication extends Application {    private static DaoMaster daoMaster;    private static DaoSession daoSession;    @Override    public void onCreate() {        super.onCreate();    }    /**     * 得到DaoMaster对象     *     * @param context     * @return     */    public static DaoMaster getDaoMaster(Context context) {        if (null == daoMaster) {            //第一个参数，上下文对象，第二个参数库名            DaoMaster.OpenHelper helper = new DaoMaster.DevOpenHelper(context, "GREENDB", null);            daoMaster = new DaoMaster(helper.getWritableDatabase());        }        return daoMaster;    }    /**     * 得到DaoSession对象     *     * @param context     * @return     */    public static DaoSession getDaoSession(Context context) {        if (daoSession == null) {            if (daoMaster == null) {                daoMaster = getDaoMaster(context);            }            daoSession = daoMaster.newSession();        }        return daoSession;    }}

• 创建一个用于操作User表的helper

  public class DBHelper {    private static DBHelper dbHelper;    private DaoSession daoSession;    private UserDao userDao;    private static Context mContext;    public DBHelper() {    }    public static DBHelper getinstance(Context context) {        if (null == dbHelper) {            dbHelper = new DBHelper();            if (null != context) {                mContext = context.getApplicationContext();                dbHelper.daoSession = MyApplication.getDaoSession(mContext);                dbHelper.userDao = dbHelper.daoSession.getUserDao();            }        }        return dbHelper;    }    /**     * 根据id查询     *     * @param id     * @return     */    public User loadUser(long id) {        return userDao.loadByRowId(id);    }    /**     * 获取所有     *     * @return     */    public List<User> loadAll() {        return userDao.loadAll();    }    /**     * 添加     *     * @param user     * @return     */    public long saveUser(User user) {        return userDao.insertOrReplace(user);    }    /**     * 根据条件查询     *     * @param where     * @param query     * @return     */    public List<User> queryUser(WhereCondition where, WhereCondition... query) {        if (null == query)            return userDao.queryBuilder().where(where).build().list();        else            return userDao.queryBuilder().where(where, query).build().list();    }    /**     * 添加多个     *     * @param users     */    public void saveUsers(final List<User> users) {        if (null == users && users.size() == 0)            return;        userDao.getSession().runInTx(new Runnable() {            @Override            public void run() {                for (int i = 0; i < users.size(); i++) {                    userDao.insertOrReplace(users.get(i));                }            }        });    }    /**     * 删除     *     * @param user     */    public void delUser(User user) {        userDao.delete(user);    }}

• activity操作代码如下

  public class MainActivity extends AppCompatActivity {    @InjectView(R.id.toolbar)    Toolbar toolbar;    @InjectView(R.id.id)    EditText id;    @InjectView(R.id.name)    EditText name;    @InjectView(R.id.age)    EditText age;    @InjectView(R.id.phone)    EditText phone;    @InjectView(R.id.insert)    Button insert;    @InjectView(R.id.getall)    Button getall;    @InjectView(R.id.update)    Button update;    @InjectView(R.id.query)    Button query;    @InjectView(R.id.getbyid)    Button getbyid;    @InjectView(R.id.inserts)    Button inserts;    @InjectView(R.id.del)    Button del;    @InjectView(R.id.msg)    TextView msg;    @InjectView(R.id.fab)    FloatingActionButton fab;    DBHelper dbHelper;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        ButterKnife.inject(this);        setSupportActionBar(toolbar);        dbHelper = DBHelper.getinstance(this);    }    @OnClick({R.id.insert, R.id.getall, R.id.update, R.id.query, R.id.getbyid, R.id.inserts, R.id.del})    public void onClick(View view) {        switch (view.getId()) {            case R.id.insert:                if (null != getUser()) {                    dbHelper.saveUser(getUser());                    showMsg(dbHelper.loadAll());                    Toast.makeText(this, "添加成功！", Toast.LENGTH_LONG).show();                }                break;            case R.id.getall:                showMsg(dbHelper.loadAll());                Toast.makeText(this, "查询成功！", Toast.LENGTH_LONG).show();                break;            case R.id.update:                if (null != getUser()) {                    User user = getUser();                    user.setId(1l);                    dbHelper.saveUser(user);                    Toast.makeText(this, "修改成功！", Toast.LENGTH_LONG).show();                    showMsg(dbHelper.loadAll());                }                break;            case R.id.query:                showMsg(dbHelper.queryUser(UserDao.Properties.Age.eq(12)));                Toast.makeText(this, "查询成功！", Toast.LENGTH_LONG).show();                break;            case R.id.getbyid:                msg.setText(dbHelper.loadUser(1).toString());                Toast.makeText(this, "查询成功！", Toast.LENGTH_LONG).show();                break;            case R.id.inserts:                break;            case R.id.del:                dbHelper.delUser(dbHelper.loadAll().get(1));                showMsg(dbHelper.loadAll());                Toast.makeText(this, "删除成功！", Toast.LENGTH_LONG).show();                break;        }    }    public User getUser() {        User user = new User();        try {            if (null != id.getText())                user.setUserId(id.getText().toString());            if (null != name.getText())                user.setUsername(name.getText().toString());            if (null != age.getText())                user.setAge(Integer.parseInt(age.getText().toString()));            if (null != phone.getText())                user.setPhone(phone.getText().toString());        } catch (Exception e) {            e.printStackTrace();            user = null;        }        return user;    }    public void showMsg(List<User> users) {        if (null != users && users.size() > 0) {            String msg = "";            for (User user : users) {                msg = msg + user.toString() + "\n";            }            this.msg.setText(msg);        } else {            this.msg.setText(null);        }    }}

• 效果如下
  

这里只涉及到基础的单表的基础操作，还有更多涉及到更复杂的或者多表操作的，还需进一步研究，对于前端，大部分应用只需要简单的操作基础数据，因此基本已经足够使用了。

github源码