转换ArrayList< JsonArray>在Java中浮动[] [] [英] Convert ArrayList<JsonArray> to float[][] in Java

问题描述

使用Gson将 ArrayList< JsonArray> 转换为 float [] [] ？

$ b $ ArrayList< JsonArray> 是一个具有以下示例格式的long二维数组：

  [[-0.0028871582，-0.0017856462，0.0078000603，0.003144495，0.0042561297，-0.026877755,0.019066211,0.050337251，-0.00062063418]，
 [ -0.6545645087,0.7474752828,1.8797838739,0.2287287200,0.0007858753,0.742472785,0.019066211,0.050337251,0.00062063418]，
 ...] 
  

人们说我应该用两次扫描每个项目并进行转换，但不知道是否有更自动化的方式。

fromJson 取第二个参数来描述你的数据。它可以是 Class code> 或 类型 。

---

Class example

 字符串json =[\ n+ 
[ -0.0028871582，-0.0017856462,0.0078000603]，\ n+ 
[-0.6545645087,0.7474752828,1.8797838739] \ n+ 
] \ n; 
 
 Gson gson = new GsonBuilder（）。create（）; 
 float [] [] r = gson.fromJson（json，float [] []。class）; （float [] a：r）{
 for（float f：a）{
 System.out.println（f）; 
 
 
 
 
 
 
 $ b 
 类型示例
 
 
 
 键入myType = new TypeToken< ArrayList< ArrayList< Float> ;>>（）{} .getType（）; 
列表<列表<浮点>> r = gson.fromJson（json，myType）; （浮动f：a）{
 System.out.println（f）; 
 for（List< Float> a：r） 
} 
} 
  
 
What is best and fastest way to convert an ArrayList<JsonArray> to float[][] using Gson?

The ArrayList <JsonArray> is a 2D array of long with this sample format:
[ [ -0.0028871582, -0.0017856462, 0.0078000603, 0.003144495, 0.0042561297, -0.026877755, 0.019066211, 0.050337251, -0.00062063418],
 [ -0.6545645087, 0.7474752828, 1.8797838739, 0.287287200, 0.0007858753, -0.742472785, 0.019066211, 0.050337251, -0.00062063418],
... ]
People say I should scan each item with two go and do the conversion but do not know if there is a more automated means for this.
解决方案
As @njzk2 mentioned fromJson takes a second parameter describing your data. It can be a Class or a Type.



Class example

String json = "[\n" +
        "    [ -0.0028871582, -0.0017856462, 0.0078000603 ],\n" +
        "    [ -0.6545645087, 0.7474752828, 1.8797838739 ]\n" +
        "]\n";

Gson gson = new GsonBuilder().create();
float[][] r = gson.fromJson(json, float[][].class);
for (float[] a: r) {
    for (float f : a) {
        System.out.println(f);
    }
}




Type example

Type myType = new TypeToken<ArrayList<ArrayList<Float>>>() {}.getType();
List<List<Float>> r = gson.fromJson(json, myType);
for (List<Float> a: r) {
    for (Float f: a) {
        System.out.println(f);
    }
}


                        
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