Android ORM框架介绍之OrmLite注解与封装

Android ORM框架介绍之OrmLite注解与封装

OrmLite库引入

compile 'com.j256.ormlite:ormlite-android:5.0'

OrmLite注解

• @DatabaseTable：用于javabean类上

public @interface DatabaseTable {    String tableName() default "";//设置表名，默认是类名    /**     * The DAO class that corresponds to this class. This is used by the {@link DaoManager} when it constructs a DAO     * internally.     */    Class<?> daoClass() default Void.class;//Dao类与这个类相关联}

• DatabaseField：用于成员变量上

public @interface DatabaseField {    public static final int DEFAULT_MAX_FOREIGN_AUTO_REFRESH_LEVEL = 2;    String columnName() default "";//表中的字段名，不设置就默认为成员变量名    DataType dataType() default DataType.UNKNOWN;//数据类型    String defaultValue() default DEFAULT_STRING;//创建表时默认数据，默认none    int width() default 0;//字段的数据大小，常用于String    boolean canBeNull() default true;//设置字段不为空，默认true    boolean id() default false;//主键，唯一，如果不设置，不能使用query,update,delete的ID方法    boolean generatedId() default false;//自增的id,默认fasle    String generatedIdSequence() default "";//用于生成此值的序列号的名称，默认none    boolean foreign() default false;//外键，关联另一个类    boolean useGetSet() default false;//使用set/get方法访问字段值    String unknownEnumName() default "";//类中使用枚举，但数据库使用一个字段与之匹配    boolean throwIfNull() default false;//如果设置true，数据库字段为none，会抛出SQLException    boolean persisted() default true;//如果设置false，表示这个字段不写到数据库中    String format() default "";//可选的格式信息，可以使用不同的字段类型。    boolean unique() default false;//唯一字段，对于所有行    boolean uniqueCombo() default false;//唯一字段，对于所有列    boolean index() default false;//是否建立索引 默认为false    boolean uniqueIndex() default false;//唯一索引 默认为false    String indexName() default "";//为这一领域的索引添加一个名字    String uniqueIndexName() default "";// 为这一领域的索引添加一个唯一的名字    boolean foreignAutoRefresh() default false;//当查询到一个外键对象时，是否自动刷新    int maxForeignAutoRefreshLevel() default DEFAULT_MAX_FOREIGN_AUTO_REFRESH_LEVEL;//为了防止无限递归或者无限循环时 需要用到该属性设置自动刷新的最高级别    boolean allowGeneratedIdInsert() default false;//插入一个ID字段是否覆盖它生成的ID的对象 默认为false    String columnDefinition() default "";//定义列，默认情况下，数据库类型是用于自动生成所需的SQL来创建列，所以该属性并不常用    boolean foreignAutoCreate() default false;//在插入一个有外键对象的对象时，是否自动插入这个外键对象    boolean version() default false;//行版本 当一个对象被更新，以防止数据损坏多个实体时更新在同一时间进行的保护    String foreignColumnName() default "";//指定关联外键的字段名，取代使用id的用法，推荐使用    boolean readOnly() default false;//字段只读}

ormlite的封装

• DataBaseHelper：用于数据库的创建，表的创建和更新

public class DataBaseHelper extends OrmLiteSqliteOpenHelper {    private static final String DB_NAME = "my.db";    private static int VERSION = 1;    private static volatile DataBaseHelper helper;    private DataBaseHelper(Context context) {        super(context, DB_NAME, null, VERSION);    }    public static DataBaseHelper getInstance(Context context) {        if (helper == null) {            synchronized (DataBaseHelper.class) {                if (helper == null) {                    helper = new DataBaseHelper(context);                }            }        }        return helper;    }    @Override    public void onCreate(SQLiteDatabase database, ConnectionSource connectionSource) {        try {            //创建表，如果需要创建很多表，需要一个个写（这里不知道怎么抽取）            TableUtils.createTable(connectionSource, User.class);        } catch (SQLException e) {            e.printStackTrace();        }    }    @Override    public void onUpgrade(SQLiteDatabase database, ConnectionSource connectionSource, int oldVersion, int newVersion) {        try {            //类似创建            TableUtils.dropTable(connectionSource, User.class, true);            onCreate(database, connectionSource);        } catch (SQLException e) {            e.printStackTrace();        }    }}

• DataBaseManager：管理数据库的增删改查操作

public class DataBaseManager<T> {    private volatile static DataBaseManager manager;    private Context context;    private Dao dao;    private DataBaseManager(Context context) {        this.context = context;    }    public static DataBaseManager getInstance(Context context) {        context = context.getApplicationContext();        if (manager == null) {            synchronized (DataBaseManager.class) {                if (manager == null) {                    manager = new DataBaseManager(context);                }            }        }        return manager;    }    @SuppressWarnings("unchecked")    public DataBaseManager createDao(T t) {        try {            if (dao == null) {                dao = DataBaseHelper.getInstance(context).getDao(t.getClass());            }            return manager;        } catch (SQLException e) {            e.printStackTrace();        }        return null;    }    /**     * 如果插入的数据存在，会更新数据     */    @SuppressWarnings("unchecked")    public int insert(T t) throws SQLException {        return dao.create(t);    }    @SuppressWarnings("unchecked")    public int insertAll(List<T> list) throws SQLException {        return dao.create(list);    }    @SuppressWarnings("unchecked")    public int update(T t) throws SQLException {        return dao.update(t);    }    @SuppressWarnings("unchecked")    public UpdateBuilder updateBuild(T t) throws SQLException {        return dao.updateBuilder();    }    @SuppressWarnings("unchecked")    public List<T> query(T t) throws SQLException {        return dao.queryForMatchingArgs(t);    }    @SuppressWarnings("unchecked")    public T queryT(T t) throws SQLException {        return (T) dao.queryForSameId(t);    }    @SuppressWarnings("unchecked")    public List<T> queryAll() throws SQLException {        return dao.queryForAll();    }    @SuppressWarnings("unchecked")    public QueryBuilder queryBuild() throws SQLException {        return dao.queryBuilder();    }    @SuppressWarnings("unchecked")    public int delete(T t) throws SQLException {        return dao.delete(t);    }    @SuppressWarnings("unchecked")    public int deleteAll(List<T> list) throws SQLException {        return dao.delete(list);    }    public void close() {        DataBaseHelper.getInstance(context).close();        dao = null;    }}

• User

@DatabaseTable(tableName = "tb_user")public class User {    @DatabaseField(generatedId = true, unique = true)//自增，唯一    private long id;    @DatabaseField(columnName = "name")//数据库列名，如果不设置默认字段名    private String name;    @DatabaseField(columnName = "age",dataType = DataType.INTEGER)    private int age;    public User(long id, String name, int age) {        this.id = id;        this.name = name;        this.age = age;    }    public User(){}    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public long getId() {        return id;    }    public void setId(long id) {        this.id = id;    }    @Override    public String toString() {        return "User{" +                "id=" + id +                ", name='" + name + '\'' +                ", age=" + age +                '}';    }}

• MainActivity

package www.zhang.com.ormlite;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.TextView;import java.sql.SQLException;import java.util.List;import java.util.Map;@SuppressWarnings("unchecked")public class MainActivity extends AppCompatActivity implements View.OnClickListener {    private DataBaseManager<User> manager;    private Button insert;    private Button update;    private Button query;    private Button queryAll;    private Button delete;    private Button deleteAll;    private TextView tv_query;    private TextView tv_queryall;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        insert = (Button) findViewById(R.id.btn1);        update = (Button) findViewById(R.id.btn2);        query = (Button) findViewById(R.id.btn3);        queryAll = (Button) findViewById(R.id.btn4);        delete = (Button) findViewById(R.id.btn5);        deleteAll = (Button) findViewById(R.id.btn6);        tv_query = (TextView) findViewById(R.id.tv_query);        tv_queryall = (TextView) findViewById(R.id.tv_queryall);        insert.setOnClickListener(this);        update.setOnClickListener(this);        query.setOnClickListener(this);        queryAll.setOnClickListener(this);        delete.setOnClickListener(this);        deleteAll.setOnClickListener(this);        try {            manager = DataBaseManager.getInstance(MainActivity.this).createDao(User.class.newInstance());        } catch (Exception e) {            e.printStackTrace();        }    }    private void deleteAll() {        try {            manager.deleteAll(manager.queryAll());        } catch (SQLException e) {            e.printStackTrace();        }    }    private void deleteData() {        try {            User user = new User();            user.setId(2);            manager.delete(user);        } catch (SQLException e) {            e.printStackTrace();        }    }    private List<User> queryAll() {        try {            return manager.queryAll();        } catch (SQLException e) {            e.printStackTrace();        }        return null;    }    private User queryData() {        try {            User user = new User();            user.setId(1);            return manager.queryT(user);        } catch (SQLException e) {            e.printStackTrace();        }        return null;    }    private void updateData() {        try {            User user = new User(1, "lisi", 25);            manager.update(user);        } catch (SQLException e) {            e.printStackTrace();        }    }    private void insertData() {        try {            User user1 = new User(1, "zhangsan", 20);            manager.insert(user1);            User user2 = new User(1, "zhangsan", 20);            manager.insert(user2);            User user3 = new User(1, "zhangsan", 20);            manager.insert(user3);            User user4 = new User(1, "zhangsan", 20);            manager.insert(user4);        } catch (SQLException e) {            e.printStackTrace();        }    }    @Override    public void onClick(View v) {        switch (v.getId()) {            case R.id.btn1:                insertData();                break;            case R.id.btn2:                updateData();                break;            case R.id.btn3:                User user = queryData();                if (user == null) {                    tv_query.setText("查询的数据不存在");                } else {                    tv_query.setText(user.toString());                }                break;            case R.id.btn4:                List<User> list = queryAll();                if (list == null) {                    tv_queryall.setText("查询的数据不存在");                } else {                    tv_queryall.setText(list.toString());                }                break;            case R.id.btn5:                deleteData();                break;            case R.id.btn6:                deleteAll();                break;        }    }}