所以我尝试使用这个json文件，但是当我尝试用jsonobject解析它时，它给了我一个错误。我试图找到类似的问题，但似乎ppl没有相同的东西。
代码生成此错误消息

Exception in thread "main" org.json.JSONException: 
        A JSONObject text must begin with '{' at 1 [character 2 line 1]

java 语：

public void readSubjects(String filename){
    obj =new JSONObject(filename.trim());
    objArr=obj.getJSONArray("subjects".trim());
    String tmpName;
    String tmpRealName;
    for(int i=0;i<objArr.length();i++){
        tmpName=objArr.getJSONObject(i).getString("subject_code");
        tmpRealName=objArr.getJSONObject(i).getString("name");
        System.out.println(tmpName + " " + tmpRealName);
    }
}

json文件：

{
    "teachers": [
        {
            "name": [
                "Peremann"
            ],
            "age": 22,
            "subject": [
                "pgr200"
            ],
            "availability": true,
            "contact_info": ""
        },
        {
            "name": "Jarand",
            "age": 23,
            "subject": "root"
        }
    ],
    "subjects": [
        {
            "subject_code": "pgr200",
            "name": "Avansert Javaprogrammering",
            "campus_priority": "Fjerdingen",
            "educationForm": "",
            "subjectProgram": "",
            "duration": "X",
            "amountOfHours": "",
            "amountOfStudents": 12
        }
    ],
    "studentGroups": [
        {
            "students": []
        }
    ],
    "rooms": [
        {
            "room_code": "F11",
            "fasilitetsstoette": "test",
            "max-capasity": 50,
            "room-size": "X"
        }
    ]}