fastjson序列化定制过滤器

fastjson在序列化时支持传入自定义的序列号过滤器，来定制序列化的结果

fastjson支持6种SerializeFilter，用于不同场景的定制序列化。

PropertyPreFilter 根据PropertyName判断是否序列化
PropertyFilter 根据PropertyName和PropertyValue来判断是否序列化
NameFilter 修改Key，如果需要修改Key,process返回值则可
ValueFilter 修改Value
BeforeFilter 序列化时在最前添加内容
AfterFilter 序列化时在最后添加内容

举个例子

public class Test  {
    public static void main(String[] args) {

        HashMap<String, Object> map = new HashMap<>();
        map.put("bizmonth","2020-12");
        map.put("cust_total_num","0");
        map.put("ventilation_total_num_1m","11");
        HashMap<String, Object> map1 = new HashMap<>();
        map1.put("bizmonth","2020-12");
        map1.put("cust_total_num","0");
        map1.put("ventilation_total_num_1m","11");
        ArrayList<HashMap<String, Object>> mapList = Lists.newArrayList(map1, map);
        System.out.println(map);
        System.out.println("---------------");
        String s = JSON.toJSONString(mapList, new ValueFilter() {
            @Override
            public Object process(Object o, String name, Object value) {
                if (name.equals("bizmonth")) {
                    return "*****";
                }
                return value;
            }
        });
        
        System.out.println(s);
    }
}

输出

[{"bizmonth":"*****","ventilation_total_num_1m":"11","cust_total_num":"0"},{"bizmonth":"*****","ventilation_total_num_1m":"11","cust_total_num":"0"}]

 应用：对json中的日期进行格式化转换

public class DateTransform {
    public static String transform(String srcData, String srcFormat, String dstFormat) {
        DateFormatEnum from = DateFormatEnum.valueOf(srcFormat);
        DateFormatEnum to = DateFormatEnum.valueOf(dstFormat);
        TemporalAccessor parse = from.parse(srcData);
        return to.format(parse);
    }

    public static void main(String[] args) {

        HashMap<String, Object> map = new HashMap<>();
        map.put("bizmonth", "2020-12");
        map.put("cust_total_num", "0");
        map.put("ventilation_total_num_1m", "11");
        HashMap<String, Object> map1 = new HashMap<>();
        map1.put("bizmonth", "2020-12");
        map1.put("cust_total_num", "0");
        map1.put("ventilation_total_num_1m", "11");
        ArrayList<HashMap<String, Object>> mapList = Lists.newArrayList(map1, map);
        System.out.println(map);
        System.out.println("---------------");
        String s = JSON.toJSONString(mapList, new ValueFilter() {
            @Override
            public Object process(Object o, String name, Object value) {
                if (name.equals("bizmonth")) {
                    return transform((String) value, "YM", "YM2");
                }
                return value;
            }
        });

        System.out.println(s);
    }
}