Android sqlite 表到 json 文件

Question

我是 json 的新手。我正在尝试将两个 Sqlite 表放入一个 json 文本文件中。我能够获取每个表并发送到文本文件，但如果我尝试从文件中读取字符串，我的结果将无效。

代码如下:

    File f = new File(Constants.DEFAULT_BACKUP_FILE_PATH);
    FileOutputStream fos = new FileOutputStream(f,true);
    PrintStream ps = new PrintStream(fos);

    String query1 = "SELECT " + COL_1  + "," + COL_2 + " FROM " + TABLE_1;
    Cursor cursor1 = db.rawQuery(query1, null);
    cursor1.moveToFirst();

    JSONObject mObject = new JSONObject();
    JSONArray tab1Array = new JSONArray();


    int i = 0;
    while (!cursor1.isAfterLast()) {
        JSONObject rObject = new JSONObject();
        try {
            rObject.put("id", cursor1.getString(cursor1.getColumnIndex(COL_1)));
            rObject.put("user", cursor1.getString(cursor1.getColumnIndex(COL_2)));

            cursor1.moveToNext();

            tab1Array.put(i, rObject);
            i++;

        } catch (JSONException e) {

            e.printStackTrace();
        }
    }


    mObject.put("TABLE1", tab1Array);
    ps.append(mObject.toString());


    String query2 = "SELECT " + COL_1  + "," + COL_2 + " FROM " + TABLE_2;
    Cursor cursor2 = db.rawQuery(query2, null);
    cursor2.moveToFirst();

    JSONObject mObject2 = new JSONObject();
    JSONArray tab2Array = new JSONArray();


    int i2 = 0;
    while (!cursor2.isAfterLast()) {
        JSONObject rObject2 = new JSONObject();
        try {
            rObject2.put("id", cursor2.getString(cursor2.getColumnIndex(COL_1)));
            rObject2.put("name", cursor2.getString(cursor2.getColumnIndex(COL_2)));

            cursor2.moveToNext();

            tab2Array.put(i2, rObject2);
            i2++;

        } catch (JSONException e) {

            e.printStackTrace();
        }
    }


    mObject2.put("TABLE2", tab1Array);
    ps.append(mObject2.toString());

我的文本文件如下所示(注意两者之间没有逗号):

{"TABLE1":[{"id":"1", "user":"Larry"},{"id":"2", "user":"Mo"},{"id": "4", "user":"Curly"},{"id":"5", "user":"Shemp"}]} {"TABLE2":[{"id":"1", "name":"Ticky"},{"id":"2", "name":"Tky"},{"id":"4", "name":"Tem"},{"id":"5", "name":"Bo"}]}

它应该是这样的: { “表格1”: [{ “编号”:“1”， “用户”:“拉里” }, { “编号”:“2”， “用户”:“莫” }, { “编号”:“4”， “用户”:“ curl ” }, { “编号”:“5”， “用户”:“羊” }], “表 2”:[{ “编号”:“1”， “名称”:“滴滴” }, { “编号”:“2”， “名字”:“Tky” }, { “编号”:“4”， “名称”:“腾” }, { “编号”:“5”， “姓名”:“博” }]

我可以通过以下方式解析 TABLE1:

        try {
        JSONObject jsonObject = new JSONObject(backup);
        JSONArray jsonArray = jsonObject.getJSONArray("TABLE1");
        for (int i=0;i<jsonArray.length();i++)     {

            JSONObject jsonObject1 = jsonArray.getJSONObject(i);
            String theId = jsonObject1.getString("_id");

但使用相同的代码无法找到 TABLE2。任何帮助都有助于正确构建导出表。

Answer 1

从代码中间删除 ps.append(mObject.toString());，并将最后两行更改为:

mObject.put("TABLE2", tab2Array);
ps.append(mObject.toString());