从文本文件中读取JSON [英] Reading JSON from a text file
问题描述
我知道一些JSON库,我现在正在研究Google-JSON,但我想要实现的只是简单的事情,我想知道你会建议什么。
I know of some JSON libs around and I'm currently looking into Google-JSON but all I want to achieve is something simple and I want to know what you would suggest.
我想要一个JSON库,让我读取一个JSON文本文件,让我把它转换成字符串,int,boolean等。
- 现在使用Json.org/java
I want a JSON library which will let me read a textfile that is in JSON and let me convert it into strings, int, boolean, etc. -- Now using Json.org/java
它可以阅读!但是!!
It can READ! BUT!!
import org.json.*;
public class readJ {
public static String MapTitle;
public static int[][] tiles;
public static void main(String[] args) {
String json =
"{"
+"'name': 'map_one.txt',"
+"'title': 'Map One',"
+"'currentMap': 4,"
+"'items': ["
+"{ name: 'Pickaxe', x: 5, y: 1 },"
+"{ name: 'Battleaxe', x: 2, y: 3 }"
+"],"
+"map': [ [ 1,3,1,1,1,24,1,1,1,1,1,1,1 ],"
+"[ 1,3,1,1,1,24,1,1,1,1,1,1,1 ],"
+"[ 1,7,1,1,1,24,1,1,24,1,1,1,1 ],"
+"[ 1,7,1,1,7,1,1,1,24,1,1,1,1 ],"
+"[ 1,7,7,7,1,24,24,24,24,1,1,1,1 ],"
+"[ 1,1,7,1,1,24,1,24,1,1,1,1,1 ],"
+"[ 1,1,1,1,1,24,1,1,1,1,1,1,1 ],"
+"[ 1,1,3,1,1,24,1,1,1,1,1,1,1 ],"
+"[ 1,3,3,1,1,24,1,1,1,1,1,1,1 ]]"
+"}";
try {
JSONObject JsonObj = new JSONObject(json);
MapTitle = JsonObj.getString("title");
tiles = JsonObj.getJSONArray("map");
}catch (JSONException er) {
er.printStackTrace();
}
System.out.println(MapTitle);
System.out.println(tiles[0][1]);
}
}
编译时我收到此错误:
When compiling I get this error:
C:\Users\Dan\Documents\readJSON\readJ.java:32: incompatible types
found : org.json.JSONArray
required: int[][]
tiles = JsonObj.getJSONArray("map");
^
1 error
Tool completed with exit code 1
推荐答案
安装 Google Gson 并创建这两个模型类
Install Google Gson and create those two model classes
public class Data {
private String name;
private String title;
private int currentMap;
private List<Item> items;
private int[][] map;
public String getName() { return name; }
public String getTitle() { return title; }
public int getCurrentMap() { return currentMap; }
public List<Item> getItems() { return items; }
public int[][] getMap() { return map; }
public void setName(String name) { this.name = name; }
public void setTitle(String title) { this.title = title; }
public void setCurrentMap(int currentMap) { this.currentMap = currentMap; }
public void setItems(List<Item> items) { this.items = items; }
public void setMap(int[][] map) { this.map = map; }
}
和
public class Item {
private String name;
private int x;
private int y;
public String getName() { return name; }
public int getX() { return x; }
public int getY() { return y; }
public void setName(String name) { this.name = name; }
public void setX(int x) { this.x = x; }
public void setY(int y) { this.y = y; }
}
并按如下方式转换您的JSON:
And convert your JSON as follows:
Data data = new Gson().fromJson(json, Data.class);
要获得标题,请执行以下操作:
To get the title just do:
System.out.println(data.getTitle()); // Map One
并获取x = 3和y = 3的地图项目:
And to get the map item at x=3 and y=3:
System.out.println(data.getMap()[3][3]); // 1
并获取第一个项目的名称
:
System.out.println(data.getItems().get(0).getName()); // Pickaxe
简单!使用 Gson#toJson()
转换另一种方式也很简单。
Easy! Converting the other way on is also simple using Gson#toJson()
.
String json = new Gson().toJson(data);
参见这个答案另一个复杂的Gson例子。
See also this answer for another complex Gson example.
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