DataWeave中多格式时区时间转UTC的实现方法

完全不用依赖第三方库，DataWeave自带的日期时间处理能力就能搞定这三种格式转UTC的需求，下面分场景给你具体实现代码：

场景1：日期时间与时区缩写分开 #

比如输入是 { "dt": "2022-01-20T15:00:00", "tz": "CST" }，先把日期字符串结合时区转成带时区的DateTime，再转成UTC格式：

%dw 2.0
output application/json
---
(payload.dt as DateTime {timezone: payload.tz}) as String {format: "uuuu-MM-dd'T'HH:mm:ss'Z'", timezone: "UTC"}

场景2：带时区偏移的日期时间字符串 #

比如输入是 "2022-01-20T15:00:00+05:30"，这种格式本身包含时区偏移，直接转成DateTime后再转UTC即可：

%dw 2.0
output application/json
---
($ as DateTime) as String {format: "uuuu-MM-dd'T'HH:mm:ss'Z'", timezone: "UTC"}

场景3：日期时间与IANA时区分开 #

比如输入是 { "dt": "2022-01-20T15:00:00", "tz": "Asia/Calcutta" }，处理逻辑和场景1一致，IANA时区的解析更准确（推荐优先用这种，避免时区缩写的歧义）：

%dw 2.0
output application/json
---
(payload.dt as DateTime {timezone: payload.tz}) as String {format: "uuuu-MM-dd'T'HH:mm:ss'Z'", timezone: "UTC"}

综合处理不同格式的通用函数 #

如果输入可能混合这三种格式，可以封装一个通用函数来统一处理：

%dw 2.0
output application/json

fun toUTC(dt: String, tz: String = "") = 
    if (dt contains "+" or dt contains "-") 
        (dt as DateTime) as String {format: "uuuu-MM-dd'T'HH:mm:ss'Z'", timezone: "UTC"}
    else if (tz != "")
        (dt as DateTime {timezone: tz}) as String {format: "uuuu-MM-dd'T'HH:mm:ss'Z'", timezone: "UTC"}
    else
        error("Missing timezone information")
---
// 测试不同输入场景
{
    case1: toUTC("2022-01-20T15:00:00", "CST"),
    case2: toUTC("2022-01-20T15:00:00+05:30"),
    case3: toUTC("2022-01-20T15:00:00", "Asia/Calcutta")
}

内容的提问来源于stack exchange，提问作者PiriyaS