pom文件导入fastjson2坐标：

 <dependency>
      <groupId>com.alibaba.fastjson2</groupId>
      <artifactId>fastjson2</artifactId>
      <version>2.0.51</version>
    </dependency>

UserVO对象：

@Data
@AllArgsConstructor
@NoArgsConstructor
public class UserVO {
    private Long id;
    private String userName;
    private String name;
    private String token;
}

java对象转json对象：

 //对象
         UserVO userVO = new UserVO(1L,"UserVo","User","0");
         //userVo对象:UserVO(id=1, userName=UserVo, name=User, token=0)
        System.out.println(userVO);
        //java对象转Json
        String jsonUserVo = JSONObject.toJSONString(userVO);
        //{"id":1,"name":"User","token":"0","userName":"UserVo"}
        System.out.println(jsonUserVo);

json对象(json字符串)转java对象：

UserVO userVO1 = JSON.parseObject(JSONObject.toJSONString(userVO),UserVO.class);
        //或者
        //UserVO userVO1 = JSON.parseObject(jsonUserVo,UserVO.class);
        //UserVO(id=1, userName=UserVo, name=User, token=0)
        System.out.println(userVO1);

其他：

 //java对象转换成json格式的字节码
        byte[]bytes=JSON.toJSONBytes(userVO);
        //读取字节码
        String s = new String(bytes);
        //result:{"id":1,"name":"User","token":"0","userName":"UserVo"}
        System.out.println(s);

json文件方式+JSONPath：

   // json文件：
"MyCar":["AstonMartin","Audio","AUDIOYYDS","AUDIOYYDS2","BENZ","BENZE","BENZYYDS","BMW",
    "BMWYYDS","BYD"],



public void testByteJson(){
        try ( InputStream fp = new FileInputStream(InfoFiledConstant.JSON_SRC))
        {
            byte[] bytes = fp.readAllBytes();
//            JSONPath path = JSONPath.of("$.MyPhone");
            //组装访问的json路径（内容）path
            JSONPath path = JSONPath.of("$.MyPhone");
            //读取字节码成Json格式
            JSONReader parse = JSONReader.of(bytes);
            JSONArray extract =(JSONArray) path.extract(parse);
            //result:ASUS
            System.out.println(extract.get(2));
        }catch (Exception e){
            e.printStackTrace();
        }

    }

其他：

    static {
        try (InputStream is = new FileInputStream(InfoFiledConstant.JSON_SRC)) {
            byte[] b = is.readAllBytes();
            s = new String(b);
        } catch (Exception e) {
            System.out.println("ErrorJsonStringRead:" + e.getMessage());
        }
    }

    private static Random r = new Random();
    private static String s;

    private static String common(String infoConstant) {
        String key;
        JSONArray common = JSONArray.parse(JSONObject.parseObject(s).get(infoConstant).toString());
        key = (String) common.get(r.nextInt(common.size()));
        return key;
    }