Question

我有学生班和统一班。创建学生实例时，学生将使用绿色制服。

class Student{
    var uniform = Uniform.uniformColor
}

class Uniform{
    static var uniformColor = "Green"
        {
        didSet(newColor){
            print("Change to \(newColor)")

        }
    }

}



let student1 = Student()
let student2 = Student()

print(student1)
print(student2)

Uniform.uniformColor = "Red"

print(Uniform.uniformColor)

print(student1.uniform)
//print Green
print(student2.uniform)
//print Green
let student3 = Student()
print(student3.uniform)
//print Red

如何将所有学生的制服颜色一次设置为红色？

Answer 1

您可以尝试创建一系列学生，将每个学生添加到其中。接下来用Failed to access the WSDL at: http://multipurpose.jelastic.servint.net/ProxyServer/ProxyServerService?wsdl. It failed with: Connection refused. at com.sun.xml.ws.wsdl.parser.RuntimeWSDLParser.tryWithMex(RuntimeWSDLParser.java:265) at com.sun.xml.ws.wsdl.parser.RuntimeWSDLParser.parse(RuntimeWSDLParser.java:246) at com.sun.xml.ws.wsdl.parser.RuntimeWSDLParser.parse(RuntimeWSDLParser.java:209) at com.sun.xml.ws.wsdl.parser.RuntimeWSDLParser.parse(RuntimeWSDLParser.java:178) at com.sun.xml.ws.client.WSServiceDelegate.parseWSDL(WSServiceDelegate.java:364) at com.sun.xml.ws.client.WSServiceDelegate.<init>(WSServiceDelegate.java:322) at com.sun.xml.ws.client.WSServiceDelegate.<init>(WSServiceDelegate.java:231) at com.sun.xml.ws.client.WSServiceDelegate.<init>(WSServiceDelegate.java:212) at com.sun.xml.ws.client.WSServiceDelegate.<init>(WSServiceDelegate.java:208) at com.sun.xml.ws.spi.ProviderImpl.createServiceDelegate(ProviderImpl.java:119) at javax.xml.ws.Service.<init>(Service.java:92) at server.proxy.ProxyServerService_Service.<init>(ProxyServerService_Service.java:50) at server.tpa.pack.TPAServerService.setServer1UrlAtProxy(TPAServerService.java:1164) at server.tpa.pack.TPAServerService.setServer1Url(TPAServerService.java:911) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at com.sun.xml.ws.api.server.MethodUtil.invoke(MethodUtil.java:93) at com.sun.xml.ws.api.server.InstanceResolver$1.invoke(InstanceResolver.java:250) at com.sun.xml.ws.server.InvokerTube$2.invoke(InvokerTube.java:149) at com.sun.xml.ws.server.sei.SEIInvokerTube.processRequest(SEIInvokerTube.java:88) at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136) at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050) at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019) at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877) at com.sun.xml.ws.server.WSEndpointImpl$2.process(WSEndpointImpl.java:419) at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:868) at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:422) at com.sun.xml.ws.transport.http.servlet.ServletAdapter.invokeAsync(ServletAdapter.java:225) at com.sun.xml.ws.transport.http.servlet.WSServletDelegate.doGet(WSServletDelegate.java:161) at com.sun.xml.ws.transport.http.servlet.WSServletDelegate.doPost(WSServletDelegate.java:197) at com.sun.xml.ws.transport.http.servlet.WSServlet.doPost(WSServlet.java:81) at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283) at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167) at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206) at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180) at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235) at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119) at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283) at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200) at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132) at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111) at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77) at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536) at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112) at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117) at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56) at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137) at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591) at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571) at java.lang.Thread.run(Thread.java:745) Caused by: java.net.ConnectException: Connection refused at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at java.net.Socket.connect(Socket.java:579) at java.net.Socket.connect(Socket.java:528) at sun.net.NetworkClient.doConnect(NetworkClient.java:180) at sun.net.www.http.HttpClient.openServer(HttpClient.java:432) at sun.net.www.http.HttpClient.openServer(HttpClient.java:527) at sun.net.www.http.HttpClient.<init>(HttpClient.java:211) at sun.net.www.http.HttpClient.New(HttpClient.java:308) at sun.net.www.http.HttpClient.New(HttpClient.java:326) at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:997) at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:933) at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:851) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1301) at java.net.URL.openStream(URL.java:1037) at com.sun.xml.ws.wsdl.parser.RuntimeWSDLParser.createReader(RuntimeWSDLParser.java:999) at com.sun.xml.ws.wsdl.parser.RuntimeWSDLParser.resolveWSDL(RuntimeWSDLParser.java:400) at com.sun.xml.ws.wsdl.parser.RuntimeWSDLParser.parse(RuntimeWSDLParser.java:231) ... 61 more遍历所有学生并将红色分配给Uniform。

Answer 2

如果您始终希望学生拥有最新的Uniform.uniformColor，请将uniform更改为计算属性：

class Student {
    var uniform: String { return Uniform.uniformColor }
}

示例：

let student1 = Student() let student2 = Student() print(student1.uniform) // Green print(student2.uniform) // Green Uniform.uniformColor = "Red" print(student1.uniform) // Red print(student2.uniform) // Red

Answer 3

为什么不将Uniform的颜色声明为实例属性并创建一个默认的初始值设定项，它始终在Uniform类中创建一个带有红色的Student？

class Student 
{  
  let uniform : Uniform

  init() {
    self.uniform = Uniform(color:"Red")
  }
}

class Uniform
{
  var color = "Green" {
    didSet(newColor){
      print("Change to \(newColor)")
    }
  }

  init(color : String) {
    self.color = color
  }
}

let student = Student()
print(student.uniform.color) // "Red"

Answer 4

var students = [Student]()
students.append(student1)
students.append(student2)
for student in students {
    student.uniform.uniformColor = "Red"
}

如何更改类的所有实例的属性值？

4 个答案: