Gson轻松解析json数据并保存到Sqlite数据库

其他 2018-12-03 05:10:51 阅读次数: 0
版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/qq_21004057/article/details/52965103

今天给大家带来的文章为通过Gson解析json数据并快速保存至数据库的文章。我们要保存是json对象数组，本文中的json数组并非从后台获取，为了演示，直接手动构造。

需要保存到数据库的是手机的品牌和型号。所以，我们需要新建一个bean实体类去保存我们的型号和品牌。在这，我先介绍2个工具，一个是Google官方的Gson解析jar包。

名为Gson.jar，这个百度下载就可以了。另外一个是序列化插件Parcelable。在setting---->>>>plugin----->搜索Parcelable。


。


好了，下面新建我们的bean，取名DeviceModelBean.java。添加属性后，右键选择Generate--->>>Parcelable，然后快速直接序列化。

package com.mero.wyt_register.bean;

import android.os.Parcel;
import android.os.Parcelable;

/**
 * Created by chenlei on 2016/10/28.
 */

public class DeviceModelBean implements Parcelable {

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public String getModel() {
        return model;
    }

    public void setModel(String model) {
        this.model = model;
    }

    public String model;//型号
    public String brand;//品牌
    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(this.model);
        dest.writeString(this.brand);
    }

    protected DeviceModelBean(Parcel in) {
        this.model = in.readString();
        this.brand = in.readString();
    }

    public static final Parcelable.Creator<DeviceModelBean> CREATOR = new Parcelable.Creator<DeviceModelBean>() {
        @Override
        public DeviceModelBean createFromParcel(Parcel source) {
            return new DeviceModelBean(source);
        }

        @Override
        public DeviceModelBean[] newArray(int size) {
            return new DeviceModelBean[size];
        }
    };
}


接下来，再看看我们的json字符串的内容。这个字符串是我按照预期目的而构造的。

json字符串内容如下：

    String jsonString = "[{\"brand\":\"华为\",\"model\":\"c8818\"},{\"brand\":\"华为\",\"model\":\"Y635\"}," +
                "{\"brand\":\"华为\",\"model\":\"Y635-CL00\"},{\"brand\":\"华为\",\"model\":\"P8 Lite\"},{\"brand\":\"华为\",\"model\":\"荣耀X2\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀Hol-T00\"},{\"brand\":\"华为\",\"model\":\"荣耀3X畅玩版\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀6\"},{\"brand\":\"华为\",\"model\":\"荣耀4C\"},{\"brand\":\"华为\",\"model\":\"荣耀X3升级版\"}," +
                "{\"brand\":\"华为\",\"model\":\"C8816\"},{\"brand\":\"华为\",\"model\":\"C8816D\"},{\"brand\":\"华为\",\"model\":\"Mate 7\"},{\"brand\":\"华为\",\"model\":\"荣耀畅玩4C\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀7\"},{\"brand\":\"华为\",\"model\":\"荣耀畅玩4C\"},{\"brand\":\"华为\",\"model\":\"荣耀7\"},{\"brand\":\"华为\",\"model\":\"荣耀4A\"}," +
                "{\"brand\":\"华为\",\"model\":\"P8\"},{\"brand\":\"华为\",\"model\":\"C2900\"},{\"brand\":\"华为\",\"model\":\"Y320\"}," +
                "{\"brand\":\"华为\",\"model\":\"C8815\"},{\"brand\":\"华为\",\"model\":\"Mate\"},{\"brand\":\"华为\",\"model\":\"Y600\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀6 Plus\"},{\"brand\":\"华为\",\"model\":\"C8817L\"},{\"brand\":\"华为\",\"model\":\"G5000\"}," +
                "{\"brand\":\"华为\",\"model\":\"C8817E\"},{\"brand:\":\"华为\",\"model\":\"荣耀6X\"},{\"brand\":\"华为\",\"model\":\"P8 Lite\"}," +
                "{\"brand\":\"华为\",\"model\":\"Ascend P8\"},{\"brand\":\"华为\",\"model\":\"荣耀畅玩4X\"},{\"brand\":\"华为\",\"model\":\"G629\"},{\"brand\":\"华为\",\"model\":\"G620\"},{\"brand\":\"华为\",\"model\":\"荣耀X2\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀3C\"},{\"brand\":\"华为\",\"model\":\"荣耀6 Plus\"},{\"brand\":\"华为\",\"model\":\"C2800\"},{\"brand\":\"华为\",\"model\":\"2601\"},{\"brand\":\"华为\",\"model\":\"G610S\"}," +
                "{\"brand\":\"华为\",\"model\":\"Ascend G302D\"},{\"brand\":\"华为\",\"model\":\"Ascend G6\"},{\"brand\":\"华为\",\"model\":\"Ascend G6\"},{\"brand\":\"华为\",\"model\":\"T8950N\"}," +
                "{\"brand\":\"华为\",\"model\":\"G610\"},{\"brand\":\"华为\",\"model\":\"C8813DQ\"},{\"brand\":\"华为\",\"model\":\"Y618\"},{\"brand\":\"华为\",\"model\":\"G630\"}," +
                "{\"brand\":\"华为\",\"model\":\"G521\"},{\"brand\":\"华为\",\"model\":\"荣耀畅玩4\"}]";

仔细一看，其实就是一些对象数组，每个对象里面有2个元素，一个品牌，一个型号。

接下来，咱们就需要把这些属性全部设置到对象数组里去。


  java.lang.reflect.Type type = new TypeToken<List<DeviceModelBean>>(){}.getType();
            Gson gson = new Gson();
            listDeviceModel = gson.fromJson(jsonString,type);
上面三行就可以将我们的json数组设置到List<DeviceModelBean>数组里去。在这里说明一下上面的用法，Gson可以通过toJson和fromJson方法分别把对象拆分成json数组和把json数组设置到对象集合中。Type是个接口，位于java.lang.reflect包下。formJson通过传入json字符串数组和type的接口对象从而设置到对象中去。

接下来，我们应该编写数据库帮助类和dao来完成数据库的操作。首先，我们先建立一个数据库帮助类DbHelper.java。

public class DbHelper extends SQLiteOpenHelper {
    private Context context;
    private  static final String dbName = "bbzs.db";
    public DbHelper(Context context){
        super(context,dbName,null,1);
        this.context = context;
    }

    //创建表
    @Override
    public void onCreate(SQLiteDatabase db) {
        String sql1 = "create table if not exists device_model_info(id integer primary key AUTOINCREMENT,model varchar(20),brand varchar(20))";
        db.execSQL(sql1);
    }
    //删除数据库
    public void deleteDb(){
        context.deleteDatabase(dbName);
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

我们可以通过创建DbHelper对象来创建一个数据库的实例和创建表。

然后我们可以写我们的Dao。

dao的完整代码如下：

public class DeviceModelDao {
    public static final String TAG = "DeviceModelDao";
    Context context;
    SQLiteDatabase db;
    List<DeviceModelBean> listDeviceModel = null;
    public  DeviceModelDao(Context context){
        this.context = context;
    }
    //Gson解析数组到对象中去
    public List<DeviceModelBean>  addObjectToList(){
        String jsonString = "[{\"brand\":\"华为\",\"model\":\"c8818\"},{\"brand\":\"华为\",\"model\":\"Y635\"}," +
                "{\"brand\":\"华为\",\"model\":\"Y635-CL00\"},{\"brand\":\"华为\",\"model\":\"P8 Lite\"},{\"brand\":\"华为\",\"model\":\"荣耀X2\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀Hol-T00\"},{\"brand\":\"华为\",\"model\":\"荣耀3X畅玩版\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀6\"},{\"brand\":\"华为\",\"model\":\"荣耀4C\"},{\"brand\":\"华为\",\"model\":\"荣耀X3升级版\"}," +
                "{\"brand\":\"华为\",\"model\":\"C8816\"},{\"brand\":\"华为\",\"model\":\"C8816D\"},{\"brand\":\"华为\",\"model\":\"Mate 7\"},{\"brand\":\"华为\",\"model\":\"荣耀畅玩4C\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀7\"},{\"brand\":\"华为\",\"model\":\"荣耀畅玩4C\"},{\"brand\":\"华为\",\"model\":\"荣耀7\"},{\"brand\":\"华为\",\"model\":\"荣耀4A\"}," +
                "{\"brand\":\"华为\",\"model\":\"P8\"},{\"brand\":\"华为\",\"model\":\"C2900\"},{\"brand\":\"华为\",\"model\":\"Y320\"}," +
                "{\"brand\":\"华为\",\"model\":\"C8815\"},{\"brand\":\"华为\",\"model\":\"Mate\"},{\"brand\":\"华为\",\"model\":\"Y600\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀6 Plus\"},{\"brand\":\"华为\",\"model\":\"C8817L\"},{\"brand\":\"华为\",\"model\":\"G5000\"}," +
                "{\"brand\":\"华为\",\"model\":\"C8817E\"},{\"brand:\":\"华为\",\"model\":\"荣耀6X\"},{\"brand\":\"华为\",\"model\":\"P8 Lite\"}," +
                "{\"brand\":\"华为\",\"model\":\"Ascend P8\"},{\"brand\":\"华为\",\"model\":\"荣耀畅玩4X\"},{\"brand\":\"华为\",\"model\":\"G629\"},{\"brand\":\"华为\",\"model\":\"G620\"},{\"brand\":\"华为\",\"model\":\"荣耀X2\"}," +
                "{\"brand\":\"华为\",\"model\":\"荣耀3C\"},{\"brand\":\"华为\",\"model\":\"荣耀6 Plus\"},{\"brand\":\"华为\",\"model\":\"C2800\"},{\"brand\":\"华为\",\"model\":\"2601\"},{\"brand\":\"华为\",\"model\":\"G610S\"}," +
                "{\"brand\":\"华为\",\"model\":\"Ascend G302D\"},{\"brand\":\"华为\",\"model\":\"Ascend G6\"},{\"brand\":\"华为\",\"model\":\"Ascend G6\"},{\"brand\":\"华为\",\"model\":\"T8950N\"}," +
                "{\"brand\":\"华为\",\"model\":\"G610\"},{\"brand\":\"华为\",\"model\":\"C8813DQ\"},{\"brand\":\"华为\",\"model\":\"Y618\"},{\"brand\":\"华为\",\"model\":\"G630\"}," +
                "{\"brand\":\"华为\",\"model\":\"G521\"},{\"brand\":\"华为\",\"model\":\"荣耀畅玩4\"}]";
        try{
            java.lang.reflect.Type type = new TypeToken<List<DeviceModelBean>>(){}.getType();
            Gson gson = new Gson();
            listDeviceModel = gson.fromJson(jsonString,type);
            Log.e("TAG",type+"");
            for(Iterator iterator = listDeviceModel.iterator();iterator.hasNext();){
                    DeviceModelBean bean = (DeviceModelBean) iterator.next();
                    Log.e(TAG,bean.getModel()+bean.getBrand());
            }
        }catch (Exception e){
            Log.e(TAG,"错误："+e.getMessage());
        }
        return listDeviceModel;
    }
    //插入数据到数据库
    public void insertModelToDb(List<DeviceModelBean> listDeviceModel){
        try{

            DbHelper dbHelper = new DbHelper(context);
            db = dbHelper.getWritableDatabase();
            //开始事务
            db.beginTransaction();
            Log.e(TAG,listDeviceModel.size()+"");
            String sql1 = "insert into device_model_info(id,model,brand) values (?,?,?)";
            for(DeviceModelBean f :listDeviceModel){
                db.execSQL(sql1,new Object[]{null,f.model,f.brand});
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            //提交
            db.setTransactionSuccessful();
            db.endTransaction();
            db.close();

        }

    }
}

创建数据库的脚本为： 

create table if not exists device_model_info(id integer primary key AUTOINCREMENT,model varchar(20),brand varchar(20))

执行插入的脚本为： 

insert into device_model_info(id,model,brand) values (?,?,?)

这里注意的是第一个为主键id，这个必须得加上integer primary key 才会自动生成。另外，主键必须为null才可以，否则一直


在代码中的用法为：

	//创建数据库和表
			DbHelper dbHelper = new DbHelper(MyApplication.getMyApplication());
			//插入数据到数据库
			DeviceModelDao dao = new DeviceModelDao(MyApplication.getMyApplication());
			dao.insertModelToDb(dao.addObjectToList());





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