Go 特殊语法

if cmd := os.Getenv("JAVA_HOME"); len(cmd) == 0 {
        fmt.Print("cmd length is 0")
    } else {
        fmt.Printf("cmd length is %d\r\n", len(cmd))
        fmt.Println(cmd)
    }

    cmd := os.Getenv("JAVA_HOME")
    if len(cmd) == 0 {
        fmt.Print("cmd length is 0")
    } else {
        fmt.Printf("cmd length is %d\r\n", len(cmd))
        fmt.Println(cmd)
    }