GreenDao3.2使用

听说GreenDao数据库效率高，那么现在开始使用它。

GreenDao项目地址

第一步
配置项目build.gradle，
在对应位置添加：

classpath 'org.greenrobot:greendao-gradle-plugin:3.2.1'mavenCentral()

修改后的文件:

// Top-level build file where you can add configuration options common to all sub-projects/modules.buildscript {    repositories {        jcenter()    }    dependencies {        classpath 'com.android.tools.build:gradle:2.3.0-beta4'        classpath 'org.greenrobot:greendao-gradle-plugin:3.2.1'        // NOTE: Do not place your application dependencies here; they belong        // in the individual module build.gradle files    }}allprojects {    repositories {        jcenter()        mavenCentral()    }}task clean(type: Delete) {    delete rootProject.buildDir}

第二步：
修改module目录下的build.gradle文件：
对应位置添加：

apply plugin: 'org.greenrobot.greendao'compile 'org.greenrobot:greendao:3.2.0'

修改后的文件：

apply plugin: 'com.android.application'apply plugin: 'org.greenrobot.greendao'android {    compileSdkVersion 25    buildToolsVersion "25.0.2"    defaultConfig {        applicationId "xyz.reginer.greendao"        minSdkVersion 18        targetSdkVersion 25        versionCode 1        versionName "1.0"        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"    }    buildTypes {        release {            minifyEnabled false            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'        }    }}dependencies {    compile fileTree(dir: 'libs', include: ['*.jar'])    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {        exclude group: 'com.android.support', module: 'support-annotations'    })    compile 'com.android.support:appcompat-v7:25.1.1'    testCompile 'junit:junit:4.12'    compile 'org.greenrobot:greendao:3.2.0'}

第三步 ：
添加greendao的数据库版本号：
生成的操作类可以不指定路径。

greendao {    schemaVersion 1}

修改后的文件：

apply plugin: 'com.android.application'apply plugin: 'org.greenrobot.greendao'android {    compileSdkVersion 25    buildToolsVersion "25.0.2"    defaultConfig {        applicationId "xyz.reginer.greendao"        minSdkVersion 18        targetSdkVersion 25        versionCode 1        versionName "1.0"        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"    }    buildTypes {        release {            minifyEnabled false            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'        }    }}greendao {    schemaVersion 1}dependencies {    compile fileTree(dir: 'libs', include: ['*.jar'])    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {        exclude group: 'com.android.support', module: 'support-annotations'    })    compile 'com.android.support:appcompat-v7:25.1.1'    testCompile 'junit:junit:4.12'    compile 'org.greenrobot:greendao:3.2.0'}

第四步：
创建实体类(数据库表，字段)
这里做下注解说明：

@Entity：告诉GreenDao该对象为实体，只有被@Entity注释的Bean类才能被dao类操作@Id：对象的Id，使用Long类型作为EntityId，否则报错。(autoincrement = true)表示主键会自增，false使用旧值@Unique：该属性值必须在数据库中是唯一值@Property：可以自定义字段名，外键不能使用该属性@NotNull：属性不能为空@Transient：使用该注释的属性不会被存入数据库的字段中@Generated：编译后自动生成的构造函数、方法等的注释，提示构造函数、方法等不能被修改

@Entitypublic class User {    //不能用int    @Id(autoincrement = true)    private Long id;    @Property(nameInDb = "name")    private String name;    @Unique    private String QQ;    private int age;    private String address;}

build之后:

package xyz.reginer.greendao;import org.greenrobot.greendao.annotation.Entity;import org.greenrobot.greendao.annotation.Id;import org.greenrobot.greendao.annotation.Property;import org.greenrobot.greendao.annotation.Unique;import org.greenrobot.greendao.annotation.Generated;/** * ----------Dragon be here!----------/ * 　　　┏┓　　　┏┓ * 　　┏┛┻━━━┛┻┓ * 　　┃　　　　　　　┃ * 　　┃　　　━　　　┃ * 　　┃　┳┛　┗┳　┃ * 　　┃　　　　　　　┃ * 　　┃　　　┻　　　┃ * 　　┃　　　　　　　┃ * 　　┗━┓　　　┏━┛ * 　　　　┃　　　┃神兽保佑 * 　　　　┃　　　┃代码无BUG！ * 　　　　┃　　　┗━━━┓ * 　　　　┃　　　　　　　┣┓ * 　　　　┃　　　　　　　┏┛ * 　　　　┗┓┓┏━┳┓┏┛ * 　　　　　┃┫┫　┃┫┫ * 　　　　　┗┻┛　┗┻┛ * ━━━━━━神兽出没━━━━━━ * 创   建:Reginer in  2017/2/15 11:18. * 联系方式:QQ:282921012 * 功能描述:bean对象 */@Entitypublic class User {    //不能用int    @Id(autoincrement = true)    private Long id;    @Property(nameInDb = "name")    private String name;    @Unique    private int QQ;    private int age;    private String address;    /**     * 这部分是我创建的     *     * @param name    昵称     * @param QQ      QQ     * @param age     年龄     * @param address 住址     */    public User(String name, int QQ, int age, String address) {        this.name = name;        this.QQ = QQ;        this.age = age;        this.address = address;    }    @Generated(hash = 964878038)    public User(Long id, String name, int QQ, int age, String address) {        this.id = id;        this.name = name;        this.QQ = QQ;        this.age = age;        this.address = address;    }    @Generated(hash = 586692638)    public User() {    }    public Long getId() {        return this.id;    }    public void setId(Long id) {        this.id = id;    }    public String getName() {        return this.name;    }    public void setName(String name) {        this.name = name;    }    public int getQQ() {        return this.QQ;    }    public void setQQ(int QQ) {        this.QQ = QQ;    }    public int getAge() {        return this.age;    }    public void setAge(int age) {        this.age = age;    }    public String getAddress() {        return this.address;    }    public void setAddress(String address) {        this.address = address;    }}

第五步：
创建数据库帮助类：

public class DbHelper extends DaoMaster.OpenHelper {    public DbHelper(Context context, String name, SQLiteDatabase.CursorFactory factory) {        super(context, name, factory);    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {        super.onUpgrade(db, oldVersion, newVersion);    }}

第六步：
创建Application类：

public class App extends Application {    private DaoSession daoSession;    @Override    public void onCreate() {        super.onCreate();        DbHelper helper = new DbHelper(this, "user.db", null);        Database db = helper.getWritableDb();        daoSession = new DaoMaster(db).newSession();    }    public DaoSession getDaoSession() {        return daoSession;    }}

第七步：
正式操作：
增：

private void add() {        //____________________保存一个————————        User user = new User("那时年少", 282921012, 25, "大连");        mUserDao.insert(user);        //____________________保存list————————        List<User> mUsers = new ArrayList<>();        for (int i = 0; i < 50; i++) {            mUsers.add(new User("那时年少" + i, i, 25, "大连"));        }        mUserDao.insertInTx(mUsers);    }

删：

private void del() {        mUserDao.deleteByKey((long) 1);//        删除单个数据//        mUserDao().delete(user);//        删除多个数据//        mUserDao().deleteInTx(userList);    }

改：

private void up() {        User user = new User((long) 3, "那时年少", 282921012, 25, "伊拉克");        mUserDao.update(user);    }

查：

private void query() {        //--------------------------查询全部---------        List<User> mUsers = mUserDao.loadAll();        // List< User> mUsers = mUserDao.queryBuilder().list();        //--------------------------条件查询---------        List<User> users = mUserDao.queryBuilder().where(UserDao.Properties.QQ.le(20)).list();        Log.d(TAG, "mUsers.size is:: " + mUsers.size() + "--- users.size is::" + users.size());    }

八：数据库升级：
借用网上一个工具类MigrationHelper：

public class MigrationHelper {    /**     * 调用升级方法     *     * @param db         db     * @param daoClasses dao.class     */    @SafeVarargs    public static void migrate(Database db, Class<? extends AbstractDao<?, ?>>... daoClasses) {        //1 新建临时表        generateTempTables(db, daoClasses);        //2 创建新表        createAllTables(db, false, daoClasses);        //3 临时表数据写入新表，删除临时表        restoreData(db, daoClasses);    }    /**     * 生成临时表，存储旧的表数据     *     * @param db         db     * @param daoClasses daoClasses     */    @SafeVarargs    private static void generateTempTables(Database db, Class<? extends AbstractDao<?, ?>>... daoClasses) {        for (Class<? extends AbstractDao<?, ?>> daoClass : daoClasses) {            DaoConfig daoConfig = new DaoConfig(db, daoClass);            String tableName = daoConfig.tablename;            if (!checkTable(db, tableName))                continue;            String tempTableName = daoConfig.tablename.concat("_TEMP");            String insertTableStringBuilder = "alter table " +                    tableName +                    " rename to " +                    tempTableName +                    ";";            db.execSQL(insertTableStringBuilder);        }    }    /**     * 检测table是否存在     *     * @param db        db     * @param tableName tableName     */    private static Boolean checkTable(Database db, String tableName) {        Cursor c = db.rawQuery("SELECT count(*) FROM sqlite_master WHERE type='table' AND name='" + tableName + "'", null);        if (c.moveToNext()) {            int count = c.getInt(0);            return count > 0;        }        return false;    }    /**     * 创建新的表结构     *     * @param db          db     * @param ifNotExists ifNotExists     * @param daoClasses  daoClasses     */    @SafeVarargs    private static void createAllTables(Database db, boolean ifNotExists, @NonNull Class<? extends AbstractDao<?, ?>>... daoClasses) {        reflectMethod(db, "createTable", ifNotExists, daoClasses);    }    /**     * 创建根删除都在NoteDao声明了，可以直接拿过来用     * dao class already define the sql exec method, so just invoke it     */    @SuppressWarnings("unchecked")    private static void reflectMethod(Database db, String methodName, boolean isExists, @NonNull Class<? extends AbstractDao<?, ?>>... daoClasses) {        if (daoClasses.length < 1) {            return;        }        try {            for (Class cls : daoClasses) {                //根据方法名，找到声明的方法                Method method = cls.getDeclaredMethod(methodName, Database.class, boolean.class);                method.invoke(null, db, isExists);            }        } catch (Exception e) {            e.printStackTrace();        }    }    /**     * 临时表的数据写入新表     *     * @param db         db     * @param daoClasses daoClasses     */    @SafeVarargs    private static void restoreData(Database db, Class<? extends AbstractDao<?, ?>>... daoClasses) {        for (Class<? extends AbstractDao<?, ?>> daoClass : daoClasses) {            DaoConfig daoConfig = new DaoConfig(db, daoClass);            String tableName = daoConfig.tablename;            String tempTableName = daoConfig.tablename.concat("_TEMP");            if (!checkTable(db, tempTableName))                continue;            // get all columns from tempTable, take careful to use the columns list            List<String> columns = getColumns(db, tempTableName);            //新表，临时表都包含的字段            ArrayList<String> properties = new ArrayList<>(columns.size());            for (int j = 0; j < daoConfig.properties.length; j++) {                String columnName = daoConfig.properties[j].columnName;                if (columns.contains(columnName)) {                    properties.add(columnName);                }            }            if (properties.size() > 0) {                final String columnSQL = TextUtils.join(",", properties);                String insertTableStringBuilder = "INSERT INTO " + tableName + " (" +                        columnSQL +                        ") SELECT " +                        columnSQL +                        " FROM " + tempTableName + ";";                db.execSQL(insertTableStringBuilder);            }            db.execSQL("DROP TABLE " + tempTableName);        }    }    private static List<String> getColumns(Database db, String tableName) {        List<String> columns = null;        Cursor cursor = null;        try {            cursor = db.rawQuery("SELECT * FROM " + tableName + " limit 0", null);            if (null != cursor && cursor.getColumnCount() > 0) {                columns = Arrays.asList(cursor.getColumnNames());            }        } catch (Exception e) {            e.printStackTrace();        } finally {            if (cursor != null)                cursor.close();            if (null == columns)                columns = new ArrayList<>();        }        return columns;    }}

在User中添加一个字段girlFriend；

重写升级方法：

@Override    public void onUpgrade(Database db, int oldVersion, int newVersion) {        super.onUpgrade(db, oldVersion, newVersion);        MigrationHelper.migrate(db, UserDao.class);    }

修改数据库版本号 +1：

schemaVersion 2

源码地址