GreenDao数据库的使用

创建Android测试项目导入相关资源

在Android项目下创建用于生成帮助类及Bean的java文件

操作数据库

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