GoMap并发冲突预防与解决

func TestConcurrent(t *testing.T) {
    var m = map[string]int{}
    // 写 map
    t.Run("write", func(t *testing.T) {
      for i := 0; i < 10000; i++ {
        m["a"] = 1
      }
    })
    // 读 map
    t.Run("read", func(t *testing.T) {
      for i := 0; i < 10000; i++ {
        _ = m["a"]
      }
    })
}

func TestConcurrent(t *testing.T) {
    var m = map[string]int{}
    t.Run("write", func(t *testing.T) {
      // 加上并行
      t.Parallel()
      for i := 0; i < 10000; i++ {
        m["a"] = 1
      }
    })
    t.Run("read", func(t *testing.T) {
      // 加上并行
      t.Parallel()
      for i := 0; i < 10000; i++ {
        _ = m["a"]
      }
    })
}

fatal error: concurrent map read and map write

func TestConcurrent(t *testing.T) {
	var m = map[string]int{}
	//  定义锁，零值就可以使用
	var mu sync.RWMutex
	t.Run("write", func(t *testing.T) {
		t.Parallel()
		for i := 0; i < 10000; i++ {
			// 锁
			mu.Lock()
			m["a"] = 1
			// 解锁
			mu.Unlock()
		}
	})
	t.Run("read", func(t *testing.T) {
		t.Parallel()
		for i := 0; i < 10000; i++ {
			// 锁
			mu.Lock()
			_ = m["a"]
			// 解锁
			mu.Unlock()
		}
	})
}

func (m *Map) Store(key, value any)

func (m *Map) Load(key any) (value any, ok bool)

func (m *Map) Delete(key any)

func (m *Map) Range(f func(key, value any) bool)

func TestConcurrent(t *testing.T) {
	// 可以使用零值
	var m sync.Map
	t.Run("write", func(t *testing.T) {
		t.Parallel()
		for i := 0; i < 10000; i++ {
			// 写
			m.Store("a", 1)
		}
	})
	t.Run("read", func(t *testing.T) {
		t.Parallel()
		for i := 0; i < 10000; i++ {
			// 读
			v, ok := m.Load("a")
			if ok {
				_ = v.(int)
			}
		}
	})
}