JAVA：类型不匹配：无法从Collection <set <iconnection>＆gt;转换到Iterator <iconnection> </iconnection> </set <iconnection>

Question

我有一个问题，这里使用Red5 0.9 Server中的Java，这里是代码

package com.hwakin.i5lc.manager;

import java.util.Iterator;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.red5.server.adapter.ApplicationAdapter;
import org.red5.server.api.IClient;
import org.red5.server.api.IConnection;
import org.red5.server.api.IScope;
import org.red5.server.api.Red5;
import org.red5.server.api.service.IServiceCapableConnection;

import com.hwakin.i5l.vo.ExternalPoint;
import com.hwakin.i5l.vo.UserInfo;
import com.hwakin.i5lc.vo.ExternalDrawInfo;

public class I5lcDrawManager extends ApplicationAdapter {
    protected static Log log = LogFactory.getLog(I5lcDrawManager.class.getName());

public void startDrawingHandler(String type,ExternalPoint point, ExternalDrawInfo data){

         try{
            IConnection Lconn = Red5.getConnectionLocal();

            IScope scope = Lconn.getScope();

            Iterator<IConnection> it = scope.getConnections();

            while (it.hasNext()) {
                IConnection conn = it.next();

                if (Lconn.equals(conn)) {
                    continue;
                }

                log.info("i5lvDrawManagerReceiver.startDrawingHandler invoked.");

                IClient client = conn.getClient();

                UserInfo userInfo =(UserInfo) client.getAttribute("userInfo");


                if (conn instanceof IServiceCapableConnection) {
                    if(userInfo.lectureInfo.sync.equals("true")){

                        ((IServiceCapableConnection) conn).invoke("invoke",new Object[]{"i5lvDrawManagerReceiver.startDrawingHandler",type,point,data});
                    }       
                }   
            }

        }catch(Exception e){
                log.debug("Exception in noticeChattingTo Method:"+e);
        }
    }
    public void drawingHandler(String type,ExternalPoint point){

         try{
            IConnection Lconn = Red5.getConnectionLocal();
            IScope scope = Lconn.getScope();

            Iterator<IConnection> it = scope.getConnections();

            while (it.hasNext()) {
                IConnection conn = it.next();

                if (Lconn.equals(conn)) {
                    continue;
                }

                log.info("i5lvDrawManagerReceiver.drawingHandler invoked.");

                IClient client = conn.getClient();

                UserInfo userInfo =(UserInfo) client.getAttribute("userInfo");


                if (conn instanceof IServiceCapableConnection) {
                    if(userInfo.lectureInfo.sync.equals("true")){

                        ((IServiceCapableConnection) conn).invoke("invoke",new Object[]{"i5lvDrawManagerReceiver.drawingHandler",type,point});

                    }

                }   
            }

        }catch(Exception e){
                log.debug("Exception in noticeChattingTo Method:"+e);
        }
    }

    public void endDrawingHandler(String type,ExternalPoint point, ExternalDrawInfo data){

         try{
            IConnection Lconn = Red5.getConnectionLocal();
            IScope scope = Lconn.getScope();

            Iterator<IConnection> it = scope.getConnections();

            while (it.hasNext()) {
                IConnection conn = it.next();

                if (Lconn.equals(conn)) {
                    continue;
                }

                log.info("i5lvDrawManagerReceiver.endDrawingHandler invoked.");

                IClient client = conn.getClient();

                UserInfo userInfo =(UserInfo) client.getAttribute("userInfo");


                if (conn instanceof IServiceCapableConnection) {
                    if(userInfo.lectureInfo.sync.equals("true")){

                        ((IServiceCapableConnection) conn).invoke("invoke",new Object[]{"i5lvDrawManagerReceiver.endDrawingHandler",type,point,data});
                    }       
                }   
            }

        }catch(Exception e){
                log.debug("Exception in noticeChattingTo Method:"+e);
        }
    }
}

错误是：

1. /opt/red5/dist/webapps/i5lecture/WEB-INF/src/com/hwakin/i5lc/manager/I5lcDrawManager.java中的错误（第29行）

   Iterator <IConnection> it = scope.getConnections();
   

类型不匹配：无法从Collection＆lt; Set＆lt; IConnection＆gt;＆gt;转换到Iterator

1. /opt/red5/dist/webapps/i5lecture/WEB-INF/src/com/hwakin/i5lc/manager/I5lcDrawManager.java中的错误（第63行）

   Iterator<IConnection> it = scope.getConnections();
   

类型不匹配：无法从Collection＆lt; Set＆lt; IConnection＆gt;＆gt;转换到Iterator＆lt; IConnection＆gt;

1. /opt/red5/dist/webapps/i5lecture/WEB-INF/src/com/hwakin/i5lc/manager/I5lcDrawManager.java中的错误（第100行）

   Iterator<IConnection> it = scope.getConnections();
   

类型不匹配：无法从Collection＆lt; Set＆lt; IConnection＆gt;＆gt;转换到Iterator＆lt; IConnection＆gt;

3个问题（3个错误）

Answer 1

听起来您的getConnections()方法会返回Collection<Set<IConnection>>，而您似乎认为它应该返回Iterator<IConnection>。

您是否忘记了对.iterator()的通话？如

Iterator<IConnection> it = scope.getConnections.iterator();

虽然从编译器错误中听起来好像你需要

Iterator<Set<IConnection>> it = scope.getConnections.iterator();

Answer 2

Collection是Iterable，而非Iterator。您不需要Iterator进行循环;增强的for循环适用于任何Iterable实现。

请改为尝试：

for (Set<IConnection>> connections : scope.getConnections()) {
  for (IConnection con : connections) {
    /* Use each 'conn' instance... */
  }
}

Answer 3

我添加了（Iterator）来解析scope.getConnection（）;

Iterator<IConnection> it = (Iterator) scope.getConnections();

然后我在函数的开头添加了@SuppressWarnings（“unchecked”）

@SuppressWarnings("unchecked")
    public void startDrawingHandler(String type,ExternalPoint point, ExternalDrawInfo data){

   // Rest of the code

}

Answer 4

您在这里看到的是一个不稳定的API。

是Iterator<IConnection> getConnections()还是Collection<Set<IConnection>> getConnections()（很好地将文档称为“获取连接迭代器。” - 评论谎言）？谷歌是你的朋友。