我将数据放入地图的代码是否有错误？

Question

我看不到我代码的错误，希望你能找到！

语言：Java IDE：日食

我创建了一个对象。此对象包含以下数据：

public class ObjectTypeBean {
   private  Map<String, String> connectedOperators = new HashMap<String, String>();

   public Map<String, String> getConnectedOperators() {
       return connectedOperators;
   }

   public void setConnectedOperators(String operatorId, String label) {
       this.connectedOperators.put(operatorId, label);
    }
}

然后我创建了这个对象的列表-class

List<ObjectTypeBean> name= new ArrayList<ObjectTypeBean>();

我正在尝试向地图添加新数据。我正在这样尝试：

for(ObjectTypeBean n:name){
   n.setConnectedOperators("one", "two");
}

但是我一调整这个我就得到一个

java.lang.UnsupportedOperationException
at java.base/java.util.AbstractMap.put(AbstractMap.java:209)
    at ObjectTypeBean.setConnectedOperators(ObjectTypeBean.java:356)
    at MyServlet.doPost(MyServlet.java:372)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at CharsetFilter.doFilter(CharsetFilter.java:31)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:836)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1839)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:834).

Answer 1

感谢您的建议，我找到了答案！

问题是，我在 ObjectTypeBean-Object 中使用了构建器。当构建器创建一个 Collections.emptyMap() 以便地图可以为空时。

我已经从构建器中删除了 connectedOperators-Map，现在没有错误了。谢谢！

我将数据放入地图的代码是否有错误？

Is there an error with my code to put data in map?

java

dictionary

put