json文件内容：

{
  "nickname":"leoops",
  "openid":"12e1f31a2d8bae8395c424752be18e02"
}

读取的代码：

public static void main(String[] args) throws FileNotFoundException {
        JSONReader reader = new JSONReader(new FileReader("/Users/leo/Documents/test.json"));
        reader.startObject();
        while (reader.hasNext()) {
            Map<String, Object> map = new HashMap<String, Object>();
            reader.readObject(map);
            System.out.println(JSON.toJSONString(map));
        }
        reader.endObject();
        reader.close();
    }

异常信息：

Exception in thread "main" com.alibaba.fastjson.JSONException: syntax error, expect {, actual string, 
    at com.alibaba.fastjson.parser.DefaultJSONParser.parseObject(DefaultJSONParser.java:219)
    at com.alibaba.fastjson.parser.DefaultJSONParser.parseObject(DefaultJSONParser.java:1051)
    at com.alibaba.fastjson.JSONReader.readObject(JSONReader.java:282)
    at com.example.DemoApplicationTests.main(DemoApplicationTests.java:30)