GreenDao

1.在工程配置的buildscript中的dependencies里添加

buildscript{    repositories{                jcenter()                mavenCentral()// 添加的代码}dependencies{classpath'com.android.tools.build:gradle:2.3.3'classpath'org.greenrobot:greendao-gradle-plugin:3.2.2'// add plugin}}

2.在项目配置的头部添加插件

apply plugin: 'org.greenrobot.greendao' // apply plugin

3.然后添加依赖

    implementation 'org.greenrobot:greendao:3.2.2' // add library    implementation 'org.greenrobot:greendao-generator:3.2.2'

4.最后初始化GreenDao的配置

greendao{    schemaVersion 1 //数据库版本号    daoPackage 'com.example.greendao.dao'  //数据库全路径    targetGenDir 'src/main/java'  //存放位置    //如果还导不进去尝试着把  targetGenDir 'src/main/java' 存放位置注释}

schemaVersion–> 指定数据库schema版本号，迁移等操作会用到;

daoPackage --> dao的包名，包名默认是entity所在的包；

targetGenDir --> 生成数据库文件的目录;

二.代码

双检锁单例模式：得到表对象

public static DbHelp getInstance() {if (instance==null){synchronized (DbHelp.class){if (instance==null){instance=new DbHelp();}}}return instance;}

//创建数据库

private DbHelp(){  DaoMaster.DevOpenHelper devOpenHelper=new DaoMaster.DevOpenHelper(GreenDaoApplication.getApp(),"s.db");//获取读写对象    DaoMaster daoMaster =new DaoMaster(devOpenHelper.getWritableDb());//获取管理器    DaoSession daoSession = daoMaster.newSession();//获取表对象    studentBeanDao = daoSession.getStudentBeanDao();}获取整个App的上下文private static GreenDaoApplicationapp;@Overridepublic void onCreate() {super.onCreate();app=this;}public static GreenDaoApplication getApp() {return app;}使用Greendao实现增删改查//添加public void insert(StudentBean studentBean){studentBeanDao.insertOrReplace(studentBean);}//删除public void delete(StudentBean studentBean){studentBeanDao.delete(studentBean);}//修改public void updata(StudentBean studentBean){studentBeanDao.update(studentBean);}//查询全部public List queryAll(){return studentBeanDao.queryBuilder().list();}

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