Groovy String类型null和empty（""）判断

复制代码public static void main(String[] args) { def a = "" def b = null if (a?.trim()){ //a为null/"" a?.trim()表达式为false println("not empty or null") } else { def c = a?.trim() println("empty or null") }}

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public static void main(String[] args) {
    def a = ""
    def b = null
    if (a?.trim()){  //a为null/""  a?.trim()表达式为false
        println("not empty or null")
    }
    else {
        def c = a?.trim()
        println("empty or null")
    }
}