简介
greenDao是一个使用于android的ORM框架,现在主流的ORM框架有OrmLite,SugarORM,Active Android,Realm以及GreenDAO.greenDao的性能远远高于同类的ORM框架,具体的测试结果官网有。
2.x示例代码
https://github.com/7449/AndroidDevelop/tree/master/greenDao
3.x示例代码
https://github.com/7449/AndroidDevelop/tree/master/greendao3.0
多表关联示例代码
https://github.com/7449/AndroidDevelop/tree/master/greendaoMultiTable
读写第三方数据表，示例代码
https://github.com/7449/AndroidDevelop/tree/master/greenDaoExternal
有时候数据表会由后台分发而不是自动生成，所以这里简单介绍下怎么使用greendao操作这种情况下的数据表
需要注意以下几点
1：android数据库操作都是在databases文件夹下，所以要把需要动的数据库复制到databases文件夹下
/**
* assets目录下的db转移到databases
*/
public void copyDBToDatabases() {
try {
String outFileName = DB_PATH + DB_NAME;
File file = new File(DB_PATH);
if (!file.mkdirs()) {
file.mkdirs();
}
File dataFile = new File(outFileName);
if (dataFile.exists()) {
dataFile.delete();
}
InputStream myInput;
myInput = getApplicationContext().getAssets().open(DB_NAME);
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
} catch (IOException e) {
Log.i(TAG, "error--->" + e.toString());
e.printStackTrace();
}
}
2：geenDao自动生成的时候table 默认为TABLENAME，默认id生成时"_id",这些生成的字段必须要和数据表中的字段一致，可以用 nameInDb="" 指定字段name和tableName
@Entity(nameInDb = "blacklist")
public class ExternalBean {
@Property(nameInDb = "id")
private Integer id;
@Property(nameInDb = "email")
private String email;
@Generated(hash = 1314000312)
public ExternalBean(Integer id, String email) {
this.id = id;
this.email = email;
}
@Generated(hash = 981826822)
public ExternalBean() {
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getEmail() {
return this.email;
}
public void setEmail(String email) {
this.email = email;
}
}
3.x更新
项目build.gradle添加
classpath 'org.greenrobot:greendao-gradle-plugin:3.2.0'
app下的build.gradle添加
apply plugin: 'org.greenrobot.greendao'
compile 'org.greenrobot:greendao:3.2.0'
//修改生成类的位置
greendao {
targetGenDir 'src/main/java/' //生成源文件的目录，默认是build目录中的(build/generated/source/greendao)
// daoPackage //生成的DAO，DaoMaster和DaoSession的包名。默认是实体的包名
// schemaVersion //当前数据库结构的版本
// generateTests //设置是否自动生成单元测
// targetGenDirTest //生成的单元测试的根目录
}
然后自定义UserBean类
@Entity
public class UserBean {
@Id
private Long id;
private String name;
private int age;
@Generated(hash = 1032023074)
public UserBean(Long id, String name, int age) {
this.id = id;
this.name = name;
this.age = age;
}
@Generated(hash = 1203313951)
public UserBean() {
}
}
注解：
@Entity 定义实体
@nameInDb 在数据库中的名字，如不写则为实体中类名
@indexes 索引
@createInDb 是否创建表，默认为true,false时不创建
@schema 指定架构名称为实体
@active 无论是更新生成都刷新
@Id
@NotNull 不为null
@Unique 唯一约束
@ToMany 一对多
@OrderBy 排序
@ToOne 一对一
@Transient 不存储在数据库中
@generated 由greendao产生的构造函数或方法
重新rebuild 一下项目，就可以看到greenDao自动生成的数据库相关类，比2.X时确实好用多了，之后用法还和以前一样
2.x使用
用greenDao实现了数据库的增删改查,确实比以前自己写SQL语句舒服多了,不用再考虑SQL语句很方便。
IDE工具：AndroidStudio
gradle引用
compile 'org.greenrobot:greendao-generator:2.2.0'
compile 'org.greenrobot:greendao:2.2.0'
Generator
单独创建一个目录，起名为sql,然后创建一个GreenDaoGenerator,注意一点是这里就要运行一下这个java类，不是app是这个java类，需要单独运行一下生成sql代码
public class MyGreenDaoGenerator {
public static void main(String[] args) throws Exception {
//版本号,包名
Schema schema = new Schema(1, "github.com.greendao.sql");
Entity user = schema.addEntity("User");
user.addIdProperty().primaryKey();
user.addStringProperty("userName").notNull();
user.addStringProperty("userSex").notNull();
new DaoGenerator().generateAll(schema, "./app/src/main/java");
}
}
最后会自动生成文件
增删改查
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private EditText userName;
private EditText userSex;
private EditText etDelete;
private EditText etUpDateId;
private EditText etUpDateName;
private EditText etUpDateSex;
private EditText etSearch;
private SQLiteDatabase writableDatabase;
private UserDao userDao;
private ListView listView;
private SimpleCursorAdapter simpleCursorAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
userName = (EditText) findViewById(R.id.userName);
userSex = (EditText) findViewById(R.id.userSex);
listView = (ListView) findViewById(R.id.list);
etDelete = (EditText) findViewById(R.id.et_delete);
etUpDateId = (EditText) findViewById(R.id.et_update_id);
etUpDateName = (EditText) findViewById(R.id.et_update_name);
etUpDateSex = (EditText) findViewById(R.id.et_update_sex);
etSearch = (EditText) findViewById(R.id.et_search);
findViewById(R.id.add).setOnClickListener(this);
findViewById(R.id.delete).setOnClickListener(this);
findViewById(R.id.update).setOnClickListener(this);
findViewById(R.id.search).setOnClickListener(this);
init();
}
private void init() {
writableDatabase = new DaoMaster.DevOpenHelper(this, "greendao", null).getWritableDatabase();
DaoSession daoSession = new DaoMaster(writableDatabase).newSession();
//得到Dao的对象
userDao = daoSession.getUserDao();
// 遍历表中所有的数据
Cursor cursor = writableDatabase.query(userDao.getTablename(), userDao.getAllColumns(), null, null, null, null, null);
String[] from = {UserDao.Properties.UserName.columnName, UserDao.Properties.UserSex.columnName};
int[] id = {android.R.id.text1, android.R.id.text2};
simpleCursorAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_2, cursor, from, id, Adapter.NO_SELECTION);
listView.setAdapter(simpleCursorAdapter);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.add:
if (!userName.getText().toString().isEmpty() && !userSex.getText().toString().isEmpty()) {
addSQLite(userName.getText().toString(), userSex.getText().toString());
userName.getText().clear();
userSex.getText().clear();
} else {
Toast.makeText(getApplicationContext(), "name sex must not null", Toast.LENGTH_LONG).show();
}
break;
case R.id.delete:
if (!etDelete.getText().toString().isEmpty()) {
deleteSQLite(Long.valueOf(etDelete.getText().toString().trim()));
etDelete.getText().clear();
} else {
Toast.makeText(getApplicationContext(), "id illegal", Toast.LENGTH_LONG).show();
}
break;
case R.id.update:
if (!etUpDateId.getText().toString().isEmpty() && !etUpDateName.getText().toString().isEmpty() && !etUpDateSex.getText().toString().isEmpty()) {
upDateSQLite(Long.parseLong(etUpDateId.getText().toString().trim()), etUpDateName.getText().toString().trim(), etUpDateSex.getText().toString().trim());
etUpDateId.getText().clear();
etUpDateName.getText().clear();
etUpDateSex.getText().clear();
} else {
Toast.makeText(getApplicationContext(), "id name sex must not null", Toast.LENGTH_LONG).show();
}
break;
case R.id.search:
if (!etSearch.getText().toString().isEmpty()) {
searchSQLite(Long.parseLong(etSearch.getText().toString().trim()));
etSearch.getText().clear();
} else {
Toast.makeText(getApplicationContext(), "id illegal", Toast.LENGTH_LONG).show();
}
break;
}
Cursor cursor = writableDatabase.query(userDao.getTablename(), userDao.getAllColumns(), null, null, null, null, null);
simpleCursorAdapter.swapCursor(cursor);
}
//add sql data
private void addSQLite(String name, String sex) {
User user = new User(null, name, sex);
userDao.insert(user);
}
//delete sql data
private void deleteSQLite(Long id) {
userDao.deleteByKey(id);
//delete sql all;
// userDao.deleteAll();
}
//update sql data
private void upDateSQLite(long id, String name, String sex) {
userDao.update(new User(id, name, sex));
}
//search sql data
private void searchSQLite(long id) {
QueryBuilder queryBuilder = userDao.queryBuilder().where(UserDao.Properties.Id.eq(id));
// .list() Returns a collection of entity classes
List user = queryBuilder.list();
// If you only want results , use .unique() method
// Person person = queryBuilder.unique();
new AlertDialog
.Builder(this)
.setMessage(user != null && user.size() > 0 ? user.get(0).getUserName() + "--" + user.get(0).getUserSex() : "data null")
.setPositiveButton("ok", null).create().show();
}
}