Q1.出现
"resource load since it is insecure" 或者
"The resource could not be loaded because the App Transport Security policy requires the use of a secure connection"（该提示不一定有，主要是第一段提示）
这两段错误提示
解决方式：
①选中info.plist
②选中Information Property List后面的加号➕
③弹框中选择App Transport Security Settings
④点击App Transport Security Settings前的箭头，再点击加号➕
⑤弹框仅有三个选项，选择Allow Arbitrary Loads
⑥将Allow Arbitrary Loads后的NO改成YES即可
Q2.出现
"Request failed: unacceptable content-type: text/html"错误提示
是由于JSon序列化有不支持的格式，即text/html
解决方式：
可通过闭包的形式往单例中添加格式支持
1 static let shareInstance: NetworkTools = { 2 let tools = NetworkTools() 3 tools.responseSerializer.acceptableContentTypes?.insert("text/html") 4 return tools 5 }()