Go 语言中的select语句详解及工作原理

select {
case <-channel1:
    // 从 channel1 接收数据时的处理逻辑
case channel2 <- value:
    // 向 channel2 发送数据时的处理逻辑
case v := <-channel3:
    // 从 channel3 接收数据并赋值给 v 的处理逻辑
default:
    // 所有通道都未就绪时的默认逻辑（可选）
}

package main
import (
    "fmt"
    "time"
)
func main() {
    ch1 := make(chan string)
    ch2 := make(chan string)
    go func() {
        time.Sleep(1 * time.Second)
        ch1 <- "from ch1"
    }()
    go func() {
        time.Sleep(2 * time.Second)
        ch2 <- "from ch2"
    }()
    select {
    case msg1 := <-ch1:
        fmt.Println("Received:", msg1)
    case msg2 := <-ch2:
        fmt.Println("Received:", msg2)
    }
}

package main
import (
    "fmt"
)
func main() {
    ch := make(chan string)
    select {
    case msg := <-ch:
        fmt.Println("Received:", msg)
    default:
        fmt.Println("No message received")
    }
}

package main
import (
    "fmt"
    "time"
)
func main() {
    ch1 := make(chan string, 1)
    ch2 := make(chan string, 1)
    select {
    case ch1 <- "to ch1":
        fmt.Println("Sent to ch1")
    case msg := <-ch2:
        fmt.Println("Received from ch2:", msg)
    default:
        fmt.Println("Nothing happened")
    }
}

package main
import (
    "fmt"
    "time"
)
func main() {
    ch := make(chan string)
    select {
    case msg := <-ch:
        fmt.Println("Received:", msg)
    case <-time.After(2 * time.Second):
        fmt.Println("Timeout after 2 seconds")
    }
}

select {}