[bug]构建MySQL到StarRocks， Flink实时同步时，decimal-> 类型值为NULL

[baisui1981]

使用MySQL 表作为源头表，表内有一个deciaml 字段 增量 同步到 starrock表中，对应的字段为null
期望：不能为空

[baisui1981]

已经修改：qlangtech/chunjun@a33ac8b

添加对DecimalData的 fastjson 序列化映射：

 static {

        com.alibaba.fastjson.serializer.ObjectSerializer decimalSerializer = new ObjectSerializer() {
            @Override
            public void write(JSONSerializer serializer, Object object, Object fieldName, Type fieldType, int features) throws IOException {
                try {
                    DecimalData value = (DecimalData) object;
                    Objects.requireNonNull(value, "callable of " + fieldName + " can not be null");
                    serializer.write(value.toString());
                } catch (Exception e) {
                    throw new IOException(e);
                }
            }
        };

        SerializeConfig.globalInstance.put(DecimalData.class, decimalSerializer);
    }

[baisui1981]

相同的issue：#242