JAVA 恶心的字符串（字符串有点复杂）转实体类

public class AlarmFeedBack {
    public Msg msg;
    public String systemMessage;
    public String alarmId;
    public String type;
    public String userId;
    public String gisMessage;
}

public class Msg {
    public long absTime;
    public Object[] adminList;
    public String alarmAddress;
    public String alarmLevel;
    public String alarmStatus;
    public String alarmTime;
    public String alarmType;
    public String deviceId;
    public List<Ext> ext;
    public String faceId;
    public String gbId;
    public String id;
    public String idCard;
    public String imageUrl;
    public double latitude;
    public String libId;
    public String libName;
    public String loginId;
    public double longitude;
    public String name;
    public Integer number;
    public Integer realAlarm;
    public String recordId;
    public Integer score;
    public String sex;
    public String source;
    public String status;
    public String targetImage;
    public String taskId;
}

public class Ext {
    public String birthday;
    public String libId;
    public String nation;
    public String sex;
    public String libName;
    public String remark;
    public String targetImage;
    public Extend extend;
    public String sceneImg;
    public Integer score;
    public String createTime;
    public String idcard;
    public String name;
    public String personId;
}

public class Extend {
    String DealWith;
    String Reason;
    String Source;
}

/**
     * 解析
     * @param str
     * @return
     */
    public static AlarmFeedBack GetAlarmFeedBackFromStr(String str){
        Map<String,String> map= com.alibaba.fastjson.JSONObject.parseObject(str,Map.class);
        Map<String,String> map1= com.alibaba.fastjson.JSONObject.parseObject(JSONObject.toJSONString(map.get("msg")),Map.class);
        String res=map1.get("ext");
        AlarmFeedBack alarmFeedBack= JSONUtil.toBean(str,AlarmFeedBack.class);
        if(res!=null&&res.length()>0){
            List<Map> maps=JSONObject.parseArray(res,Map.class);
            String ss= maps.get(0).get("extend").toString();
            List<Ext>exts=JSONUtil.toList(JSONUtil.parseArray(res),Ext.class);
            alarmFeedBack.getMsg().setExt(exts);
            if(ss!=null&&ss.length()>0){
                Extend extend=JSONUtil.toBean(ss,Extend.class);
                alarmFeedBack.getMsg().getExt().get(0).setExtend(extend);
            }
        }
        return alarmFeedBack;
    }

String str="{\"msg\":{\"absTime\":1589882783000,\"adminList\":[],\"alarmAddress\":\"沪亭南路姚北路北侧南向北1HG\",\"alarmLevel\":\"1\",\"alarmStatus\":\"0\",\"alarmTime\":1589882783000,\"alarmType\":\"2\",\"deviceId\":\"5d7c562f-f31b-4f25-a306-72358341ee63\",\"ext\":\"[{\\\"birthday\\\":\\\"未知\\\",\\\"libId\\\":\\\"550\\\",\\\"nation\\\":\\\"未知\\\",\\\"sex\\\":\\\"0\\\",\\\"libName\\\":\\\"布控中心重点人员 - T3\\\",\\\"remark\\\":\\\"级联布控人员告警\\\",\\\"targetImage\\\":\\\"http://15.210.56.40:6120/pic?2ddf32i6c-e*292198143b8b--6df4b688b14e9i3b2*=9d5s5*=0dpi*=1d5i7t5pe*m5i7-=9906485zcd8s=8i01=\\\",\\\"extend\\\":\\\"{\\\\\\\"DealWith\\\\\\\":\\\\\\\"现场风洞道口任务，无需处置\\\\\\\",\\\\\\\"Reason\\\\\\\":\\\\\\\"支撑现场风洞道口任务\\\\\\\",\\\\\\\"Source\\\\\\\":\\\\\\\"刘迪冰\\\\\\\"}\\\",\\\"sceneImg\\\":\\\"http://15.209.59.111:8080/SJKKPIC_1400/CJ/20200519/31011710051321035012/310117100513210350120220200519180623269100.jpg\\\",\\\"score\\\":94,\\\"createTime\\\":\\\"2020-05-19 18:09:55\\\",\\\"idcard\\\":\\\"440922197305180614\\\",\\\"name\\\":\\\"刘关平\\\",\\\"personId\\\":\\\"310117100513210350120220200519180623396370663590\\\"}]\",\"faceId\":\"310117100513210350120220200519180623396370663590\",\"gbId\":\"31011710051321035012\",\"id\":\"a376886d-90e7-47bd-92a9-9d87916ff5bc\",\"idCard\":\"440922197305180614\",\"imageUrl\":\"http://15.209.59.114:8080/SJKKPIC_1400/OTHER/20200519/31011710051321035012/310117100513210350120220200519180623269131.jpg\",\"latitude\":31.112101,\"libId\":\"550\",\"libName\":\"布控中心重点人员 - T3\",\"loginId\":\"0ad29676-2e1d-40ca-b44a-ede03a187095\",\"type\":\"FACE_ALARM\",\"userId\":\"b2d589d1-4b66-4d11-9960-103b98596d1a\",\"gisMessage\":\"0\"}";
        AlarmFeedBack res= ParsePoliceSit.GetAlarmFeedBackToStr(str);