044 Android 数据库框架GreenDao实战使用

1.添加记录(SQLite 增)

2.删除记录(SQLite 删)

3.修改记录(SQLite 改)

4.查询记录(SQLite 查)

<1> DAO查询

 <2>QueryBuilder查询

<4>Query重复查询

<5>常用的查询方法含义

<6>调试技巧

.5.java后台代码

新建2个java类(HMROpenHelper、MyGreenDaoApplication)

(1)HMROpenHelper代码

package com.example.lucky.mygreendaotest;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;

import com.example.lucky.mygreendaotest.gen.DaoMaster;

//数据库创建工具类
public class HMROpenHelper extends DaoMaster.OpenHelper {
    //构造函数，参数2 name为数据库名称
    public HMROpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory) {
        super(context, name, factory);
    }
}

(2)MyGreenDaoApplication

package com.example.lucky.mygreendaotest;

import android.app.Application;
import android.database.sqlite.SQLiteDatabase;

import com.example.lucky.mygreendaotest.gen.DaoMaster;
import com.example.lucky.mygreendaotest.gen.DaoSession;

/*注意：MyGreenDaoApplication类继承Application,需要在AndroidManifest.xml文件中进行相关设置
android:name=".MyGreenDaoApplication"
MyGreenDaoApplication类的作用是封装数据库对象*/

public class MyGreenDaoApplication extends Application {
    private SQLiteDatabase db;   //SQLiteDatabase数据库对象
    private DaoMaster daoMaster; //daoMaster对象
    private DaoSession daoSession; //daoSession对象
    public  static MyGreenDaoApplication instances; //声明本类的实例对象

    @Override
    public void onCreate() {
        super.onCreate();
        instances=this; //给实例对象赋值
        setDatabase();
    }

    private void setDatabase() {
        //创建数据库
        HMROpenHelper hmrOpenHelper=new HMROpenHelper(this,"mydb1",null);
        db=hmrOpenHelper.getWritableDatabase(); //获取数据库对象
        daoMaster=new DaoMaster(db);  //获取DaoMaster对象
        daoSession=daoMaster.newSession();

    }

    //获取instances 对象
    public  static MyGreenDaoApplication getInstances(){
        return instances;
    }

    //获取daoSession对象
    public DaoSession getDaoSession(){
        return daoSession;
    }

    public SQLiteDatabase getDb(){
        return db;
    }
}

(2)MainActivity代码

package com.example.lucky.mygreendaotest;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

import com.example.lucky.mygreendaotest.gen.UserDao;

import org.greenrobot.greendao.query.Query;
import org.greenrobot.greendao.query.QueryBuilder;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private TextView tv_result;
    private UserDao userDao;
    private List<User> userList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv_result=findViewById(R.id.tv_result);
        userList=new ArrayList<>();
        QueryBuilder.LOG_SQL=true;     //显示SQL语句(可在控制台的Run窗口中看到SQL语句)
        QueryBuilder.LOG_VALUES=true;  //显示SQL语句的值
        userDao=MyGreenDaoApplication.getInstances().getDaoSession().getUserDao();
        userDao.deleteAll(); //清空表中的所有数据
//        insertOneRecord(); //插入一条数据
//        queryOneByName();  //根据姓名查询记录
        insertManyRecord(); //插入多条记录
//        deleteByName();     //根据姓名删除记录
//        userDao.deleteByKey((long)12); //通过主键值删除记录
//        updateUser();    //修改数据表的数据
//        queryList();     //查询多条记录
//        loadOneById();
//        queryMany();
        queryRepeat();

        //在控制台输出语句
//        System.out.println("like");  //方式1
//        Log.d("002","linda");//方式2
        try {
            InputStream input=getResources().openRawResource(R.raw.user);//xiaohuat是我的文件名，这里应该根据具体文件更改
            Reader reader=new InputStreamReader(input);
            BufferedReader br=new BufferedReader(reader);
            String str;
            while ((str=br.readLine())!=null){
                System.out.println(str);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //插入一条数据记录
    private void insertOneRecord(){
        User user=new User(); //实例化实体类对象
        user.setName("lucky");
        user.setUsercode("007");
        user.setUserAddress("天台县");
        userDao.insert(user);
    }

    //插入多条数据记录
    private void insertManyRecord(){
        List<User> userList=new ArrayList<>();
        User user1=new User();
        user1.setName("linda");
        user1.setUsercode("001");
        user1.setUserAddress("杭州");

        User user2=new User();
        user2.setName("jack");
        user2.setUsercode("002");
        user2.setUserAddress("苏州");

        User user3=new User();
        user3.setName("lily");
        user3.setUsercode("003");
        user3.setUserAddress("南京");

        User user4=new User();
        user4.setName("pink");
        user4.setUsercode("004");
        user4.setUserAddress("湖州");
        userList.add(user1);
        userList.add(user2);
        userList.add(user3);
        userList.add(user4);
        userDao.insertInTx(userList);
    }

    //单条数据查询
    private void queryOneByName(){
        User user=userDao.queryBuilder().where(UserDao.Properties.Name.eq("lucky")).build().unique();
        if(user!=null){
            tv_result.setText("添加一条记录的结果为："+"

"+"id:"+user.getId()
            +"
"+"姓名："+user.getName()
            +"
"+"地址"+user.getUserAddress()
            +"
"+"用户编号："+user.getUsercode());
        }
    }

    private void queryList(){
        String resultStr="显示结果为："+"

";
        List<User> userList=userDao.loadAll();
        int i=0;
        for (User user : userList) {
            i=i+1;
            resultStr=resultStr+"第"+i+"条记录的结果："+"id:"+user.getId()+
                    "
"+"姓名："+user.getName()+"
"+"地址："+user.getUserAddress()+"

";

        }
        tv_result.setText(resultStr);
    }

    //根据姓名删除记录
    private void deleteByName(){
        QueryBuilder queryBuilder=userDao.queryBuilder();
        List<User> userList=queryBuilder.where(UserDao.Properties.Name.eq("linda")).list();
        for (User user : userList) {
            userDao.delete(user);
        }
    }

    private void updateUser(){
        //注意：一个实体类对象，相当于数据表中的一条记录
        User user=userDao.queryBuilder().where(UserDao.Properties.Name.eq("linda")).build().unique(); //查询数据表中姓名为linda的一条记录
        user.setUserAddress("上海");
        userDao.update(user); //更新数据表中的数据
    }

    //查询一条记录
    private void loadOneById(){
        User user= null;
        try {
            user = userDao.load((long) 15);
        } catch (Exception e) {
            e.printStackTrace();
        }
        tv_result.setText("Load一条记录的结果：
"+"id:"+user.getId()+"
姓名："+user.getName()+
        "
地址："+user.getUserAddress());
    }

    //查询多条语句
    private void queryMany(){
        QueryBuilder queryBuilder=userDao.queryBuilder();
//        挑选名字中带有"in"的数据，并按降序排列
//        List<User> userList=queryBuilder.where(UserDao.Properties.Name.like("%in%"))
//                .orderDesc(UserDao.Properties.Id).list();
        List<User> userList=queryBuilder.where(UserDao.Properties.Name.like("%in%"),
                UserDao.Properties.UserAddress.eq("杭州")).list();
        queryResultShow(userList);
    }

    private void queryResultShow(List<User> userList) {
        if(userList!=null){
            String resultStr="查询结果为："+"

";
            int i=0;
            for (User user : userList) {
                i=i+1;
                resultStr=resultStr+"第"+i+"条记录为：
"+"id:"+user.getId()+"
姓名："+user.getName()+
                        "
地址："+user.getUserAddress()+"

";
                tv_result.setText(resultStr);
            }
        }
    }

    private void queryRepeat(){
        Query query=userDao.queryBuilder().where(UserDao.Properties.Name.like("%in%"),
                UserDao.Properties.UserAddress.like("湖%")).build();
        query.setParameter(0,"%il%");
        query.setParameter(1,"%京");
        List<User> userList=query.list();
        queryResultShow(userList);
    }
}