Golang 函数并发编程的最佳实践：如何解决常见的并发问题？

package main

import (
    "fmt"
    "sync"
)

// BankAccount represents a bank account.
type BankAccount struct {
    balance int
    lock    sync.Mutex
}

// Deposit deposits money to the account.
func (a *BankAccount) Deposit(amount int) {
    a.lock.Lock()
    defer a.lock.Unlock()
    a.balance += amount
}

// Withdraw withdraws money from the account.
func (a *BankAccount) Withdraw(amount int) {
    a.lock.Lock()
    defer a.lock.Unlock()
    a.balance -= amount
}

// GetBalance returns the account balance.
func (a *BankAccount) GetBalance() int {
    a.lock.Lock()
    defer a.lock.Unlock()
    return a.balance
}

func main() {
    // Create a bank account with an initial balance of 100.
    account := &BankAccount{balance: 100}

    // Create goroutines to deposit and withdraw money concurrently.
    go account.Deposit(50)
    go account.Withdraw(25)

    // Wait for the goroutines to finish.
    fmt.Println(account.GetBalance()) // Output: 125
}

package main

import (
    "fmt"
    "sync"
    "time"
)

func main() {
    // Create a channel with a buffer size of 1.
    ch := make(chan int, 1)

    // Create goroutine A.
    go func() {
        // Send a message to B.
        time.Sleep(time.Second)
        select {
        case ch <- 1:
            fmt.Println("A sent a message to B.")
        default:
            fmt.Println("Channel full, cannot send message.")
        }
    }()

    // Create goroutine B.
    go func() {
        // Receive a message from A.
        var msg int
        select {
        case msg = <-ch:
            fmt.Println("B received a message from A:", msg)
        case <-time.After(time.Second * 2):
            fmt.Println("Timeout waiting for message.")
        }
    }()

    // Wait for the goroutines to finish.
    time.Sleep(time.Second * 3)
}

package main

import (
    "fmt"
    "io/ioutil"
    "os"
)

func main() {
    // Open a file.
    file, err := os.Open("data.txt")
    if err != nil {
        // Handle error.
    }

    // Defer closing the file until the function returns.
    defer file.Close()

    // Read from the file.
    data, err := ioutil.ReadAll(file)
    if err != nil {
        // Handle error.
    }

    // Use the data.
    fmt.Println(data)
}