如果特定字符串不在文本文件中，则返回False

def check_string_in_file(file_path, target_string):
    try:
        with open(file_path, 'r') as file:
            content = file.read()
            if target_string in content:
                return True
            else:
                return False
    except FileNotFoundError:
        print(f"The file {file_path} does not exist.")
        return False
    except Exception as e:
        print(f"An error occurred: {e}")
        return False

# 使用示例
file_path = 'example.txt'
target_string = 'Hello, World!'
result = check_string_in_file(file_path, target_string)
print(result)  # 输出：True 或 False