Ormlite數據庫的基本實現

一、最近在求職發現好多公司都有詢問“你有技術博客麼？”這個問題，因此，本人爲了以後發展在此寫下第一篇博客，關於Ormlite的介紹，話不多說。
1. 依賴

    compile 'com.j256.ormlite:ormlite-android:4.48'
    compile 'com.j256.ormlite:ormlite-core:4.48'

2. Bean 等同於 表信息

@DatabaseTable(tableName = "product")
public class Product {
    @DatabaseField(generatedId = true)
        public int id;
        @DatabaseField(columnName = "productId", unique = true)
            public int productId;
            @DatabaseField(columnName = "name")
            public String name;

    public Product() {
    }

    public Product(int id, int productId, String name) {
        this.id = id;
        this.productId = productId;
        this.name = name;
    }

    //假數據
    public Product(int productId){
        this.productId = productId;
        this.name = "product"+productId;
    }

    @Override
    public String toString() {
        return "Product{" +
                "id=" + id +
                ", produceId=" + productId +
                ", name='" + name + '\'' +
                '}';
    }
}

3. 列表內容

public class OrmDBOpenHelper extends OrmLiteSqliteOpenHelper {

        private static OrmDBOpenHelper ormDBOpenHelper;
        public OrmDBOpenHelper(Context context) {
            super(context, "user.db", null, 1);
        }

    public static synchronized OrmDBOpenHelper getInstance(Context context){
        if (ormDBOpenHelper == null){
            synchronized (OrmDBOpenHelper.class){
                if (ormDBOpenHelper == null){
                    ormDBOpenHelper = new OrmDBOpenHelper(context);
                }
            }
        }
        return ormDBOpenHelper;
    }

    /**
     * 創建表,可創建多個表
     * @param database
     * @param connectionSource
     */
    @Override
    public void onCreate(SQLiteDatabase database, ConnectionSource connectionSource) {
        try {
            TableUtils.createTable(connectionSource, Product.class);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 更新表，可更新多個表
     * @param database
     * @param connectionSource
     * @param oldVersion
     * @param newVersion
     */
    @Override
    public void onUpgrade(SQLiteDatabase database, ConnectionSource connectionSource, int oldVersion, int newVersion) {
        try {
            TableUtils.dropTable(connectionSource, Product.class, true);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    //獲取操作數據庫的DAO
    public Dao<Product, Integer> producDao;

    public Dao<Product, Integer> getProductDao() throws SQLException {

        if (producDao == null){
            producDao = getDao(Product.class);
        }
        return producDao;
    }

    /**
     * 關閉操作數據庫的DAO
     */
    @Override
    public void close() {
        super.close();
        producDao = null;
    }
}

4、佈局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btn_add"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="ADD"/>

        <Button
            android:id="@+id/btn_query"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Query"/>

        <Button
            android:id="@+id/btn_update"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Update"/>

        <Button
            android:id="@+id/btn_delete"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Delete"/>


    </LinearLayout>

    <TextView
        android:id="@+id/tv_show"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</LinearLayout>

5、主方法

public class MainActivity extends AppCompatActivity {

    @Bind(R.id.btn_add)
    Button btnAdd;
    @Bind(R.id.btn_query)
    Button btnQuery;
    @Bind(R.id.btn_update)
    Button btnUpdate;
    @Bind(R.id.btn_delete)
    Button btnDelete;
    @Bind(R.id.tv_show)
    TextView tvShow;

    private Dao<Product, Integer> mProductDao;
    private List<Product> mProducts;
    private OrmDBOpenHelper mOrmDBOpenHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);

        init();
    }

    private void init() {
        mOrmDBOpenHelper = OrmDBOpenHelper.getInstance(this);
        try {
            mProductDao = mOrmDBOpenHelper.getProductDao();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    @OnClick({R.id.btn_add, R.id.btn_query, R.id.btn_update, R.id.btn_delete})
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.btn_add:
                add();
                break;
            case R.id.btn_query:
                query();
                break;
            case R.id.btn_update:
                update();
                break;
            case R.id.btn_delete:
                delete();
                break;
        }
    }

    private void add() {
        for (int i = 0; i < 5; i++) {
            try {
                mProductDao.create(new Product(100 + i));
            } catch (SQLException e) {
                e.printStackTrace();
                System.out.println(e.getMessage());
            }
        }
    }

    private void query() {
        try {
            mProducts = mProductDao.queryForAll();
            showResult(mProducts.toString());
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }


    private void update() {
        if (mProducts != null && mProducts.size() > 0) {
            Product product = mProducts.get(0);
            product.name = "我被修改了 (:";
            try {
                mProductDao.update(product);
                query();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    private void delete() {
        if (mProducts != null && mProducts.size() > 0) {
            Product product = mProducts.get(0);
            try {
                mProductDao.delete(product);
                query();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    private void showResult(String s) {
        tvShow.setText(s);
    }

    @Override
    protected void onDestroy() {
        mOrmDBOpenHelper.close();
        super.onDestroy();
    }
}

總結：實現起來其實很簡單，我這裏寫了數據庫的僞代碼。
模擬器結果：