GreenDao的使用

1.创建一个Java工程

1-1.引包:

加入jar包:

右键:add to build path:

编译后:

(eclipse需要两个包,Android studio只需要后一个包)

1-2.创建Java文件

1-2-1.建包(最好和你的工程包名相同)
1-2-2.在与src同级的目录下创建一个名为src-gen的包

1-2-3.创建java文件

package com.example.greendao;import java.io.IOException;import de.greenrobot.daogenerator.DaoGenerator;import de.greenrobot.daogenerator.Entity;import de.greenrobot.daogenerator.Schema;public class GreenDao {    public static void main(String args[]) {        String path = "src-gen";        Schema schema = new Schema(1, "com.example.greendao");//生成的类的路径        addEntity(schema);//调用静态方法        try {            new DaoGenerator().generateAll(schema, path);        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    public static void addEntity(Schema schema) {        Entity entity = schema.addEntity("Student");//Student:生成的实体类类名        entity.addLongProperty("_id").primaryKey().autoincrement();        //entity.addIdProperty().primaryKey().autoincrement();//主键的两种不同的写法        entity.addStringProperty("name");        entity.addStringProperty("sex");        entity.addStringProperty("age");        entity.addStringProperty("number");        entity.addLongProperty("grade");        //一个表一个实体类,如果还要创建其他的表,可以在这里接着创建Entity对象    }}

1-2-4.编译后的结果

注:如果是eclipse,可以直接移到Android工程与src同级目录下.

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如果是Android studio,可以直接将生成的文件拷贝到studio里.

2.创建Android工程

2-1.引包

compile 'de.greenrobot:greendao:2.0.0'

2-2.在BaseApplication中创建DaoMaster单例模式对象并获取DaoSession对象

package com.example.greendaodemo;import android.app.Application;import android.content.Context;public class BaseApplication extends Application {    private static DaoMaster daoMaster;    private static DaoSession daoSession;    private static Context mContext;    @Override    public void onCreate() {        super.onCreate();        if (mContext == null) {            mContext = getApplicationContext();        }    }    public static Context getmContext() {        return mContext;    }// 获取DaoMaster单例模式对象    public static DaoMaster getDaoMaster() {        if (daoMaster == null) {            DaoMaster.DevOpenHelper helper =                    new DaoMaster.DevOpenHelper(mContext, Constants.DATABASE_NAME, null);            daoMaster = new DaoMaster(helper.getWritableDatabase());        }        return daoMaster;    }    //获取DaoSession对象    public static DaoSession getDaoSession() {        if (daoSession == null) {            if (daoMaster == null) {                daoMaster = getDaoMaster();            }            daoSession = daoMaster.newSession();        }        return daoSession;    }}

2-3.创建dbHelper类

package com.example.greendaodemo;import java.util.List;import de.greenrobot.dao.query.QueryBuilder;public class StudentDBHelper {    //创建单例模式    private static StudentDBHelper instance;    //从BaseApplication获得的DaoSession单例对象    private static DaoSession daoSession;    //与单例模式搭配使用,保证只有一个实例对象    private StudentDBHelper() {    }    public static StudentDBHelper getInstance() {        if (instance == null) {            instance = new StudentDBHelper();            daoSession = getDaoSession();        }        return instance;    }    public static DaoSession getDaoSession() {        if (daoSession == null) {            daoSession = BaseApplication.getDaoSession();        }        return daoSession;    }    //返回数据库表的条数,返回值是long型    public long getCount() {        return daoSession.getStudentDao().count();    }    //插入    //1.插入集合,无返回值    public void insertList(List<Student> entities) {        daoSession.getStudentDao().insertOrReplaceInTx(entities);    }    //2.插入对象,返回值是long型    public long insert(Student entity) {        return daoSession.getStudentDao().insert(entity);    }    //删除方法,无返回值    public void delete(Student entity) {        daoSession.getStudentDao().delete(entity);    }    //根据某一字段查询,返回值为一个集合    public List<Student> queryType(String username) {        QueryBuilder<Student> db = daoSession.getStudentDao().queryBuilder();        //限制每次取多少数据        db.limit(20);        //定义查询条件 and关系        db.where(StudentDao.Properties.Name.eq(username));        return db.list();    }    public List<Student> queryByName(String name, String sex) {        QueryBuilder<Student> db = daoSession.getStudentDao().queryBuilder();        db.where(StudentDao.Properties.Name.eq(name),                StudentDao.Properties.Age.eq(sex));        return db.list();    }    public List<Student> query(String name) {        return daoSession.getStudentDao().queryBuilder().where(StudentDao.Properties.Name.eq(name)).list();    }}

3.用法