轻量级的数据库GreenDao的整合

数据库的选择

之前在项目中使用的是Xutils里面封装的数据库模块，操作起来也是简便好用，但是由于xutils的注解采用的是反射机制，在性能上不是很友好，于是拿来GreenDao试着玩玩。
GreenDao git首页可以看到一句介绍

greenDAO is a light & fast ORM solution for Android that maps objects to SQLite databases.

妥，本篇不讲GreenDao的实现原理，说明一下配置过程以及遇到的坑。

gradle配置

外层需要全局引入GreenDao的插件

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'org.greenrobot:greendao-gradle-plugin:3.2.2'
    }
}

然后在内部的gradle apply以及依赖相关的包

apply plugin: 'com.android.application'
//applygreendao插件
apply plugin: 'org.greenrobot.greendao'

 compile 'org.greenrobot:greendao:3.2.2'
 compile 'net.zetetic:android-database-sqlcipher:3.5.1@aar'

上面compile 'net.zetetic:android-database-sqlcipher:3.5.1@aar'的导入也是在配置过程中遇到的坑后面会解释一下为什么加这一句。

greenDao配置及使用

首先在Application中初始化

public class MyApplication extends Application {

    public static MyApplication INSTANCE;
    public static final boolean ENCRYPTED = true;
    private DaoSession mDaoSession;

    @Override
    public void onCreate() {
        super.onCreate();
        INSTANCE = this;
        DaoMaster.DevOpenHelper help = new DaoMaster.DevOpenHelper(this, ENCRYPTED ? "bear-db-encrypted" : "bear-db");
        //此处有坑
        Database db = ENCRYPTED ? help.getEncryptedWritableDb("admin") : help.getWritableDb();
        mDaoSession = new DaoMaster(db).newSession();
    }

    public DaoSession getDaoSession() {
        return mDaoSession;
    }
}

下面建立一个数据表来试试，那先来个User表来试玩一下。新建UserBean class

@Entity(indexes = {
        //index 值是拿表中的account作为索引，且索引是唯一不可重复的
        @Index(value = "account",unique = true)
})
public class UserBean {
    //声明一个主键值
    @Id
    public long id;
    public String account;
    public String passWord;
    public String mobile;
    public String email;
}

建立完之后点一下Android Studio运行左边的小锤子make project后就会预编译出一个比较长的类了。

@Entity(indexes = {
        @Index(value = "account",unique = true)
})
public class UserBean {
    @Id
    public long id;
    public String account;
    public String passWord;
    public String mobile;
    public String email;
@Generated(hash = 1328729131)
public UserBean(long id, String account, String passWord, String mobile,
        String email) {
    this.id = id;
    this.account = account;
    this.passWord = passWord;
    this.mobile = mobile;
    this.email = email;
}
@Generated(hash = 1203313951)
public UserBean() {
}
public long getId() {
    return this.id;
}
public void setId(long id) {
    this.id = id;
}
public String getAccount() {
    return this.account;
}
public void setAccount(String account) {
    this.account = account;
}
public String getPassWord() {
    return this.passWord;
}
public void setPassWord(String passWord) {
    this.passWord = passWord;
}
public String getMobile() {
    return this.mobile;
}
public void setMobile(String mobile) {
    this.mobile = mobile;
}
public String getEmail() {
    return this.email;
}
public void setEmail(String email) {
    this.email = email;
}

}

Ok，表已经建立完毕，现在试着插条数据进去玩玩

 UserBean userBean = new UserBean();
        userBean.setId((long)1);
        userBean.setAccount("123456789");
        userBean.setPassWord("111111qq");
        userBean.setEmail("xxx@xx.com");
        userBean.setMobile("123456789");
        UserBeanDao dao = MyApplication.INSTANCE.getDaoSession().getUserBeanDao();
    

开始运行后，Crash 没错就是crash，wocao，明明是按照官网的配置一个个来的嘛。折腾几次终于发现少依赖了一个包，就是前面讲的使用加密的数据库需要导入compile 'net.zetetic:android-database-sqlcipher:3.5.1@aar'。总算是走通了。

greenDao的详细使用以及介绍

可以看其他大神的博客：http://www.jianshu.com/p/e6c52fb7103d