今天在测试HTTPURLConnection时报了一个这样的错：
1 java.net.ConnectException: Connection refused: connect 2 at java.net.PlainSocketImpl.socketConnect(Native Method) 3 at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) 4 at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) 5 at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) 6 at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) 7 at java.net.Socket.connect(Socket.java:525) 8 at java.net.Socket.connect(Socket.java:475) 9 at sun.net.NetworkClient.doConnect(NetworkClient.java:163) 10 at sun.net.www.http.HttpClient.openServer(HttpClient.java:394) 11 at sun.net.www.http.HttpClient.openServer(HttpClient.java:529) 12 at sun.net.www.http.HttpClient.<init>(HttpClient.java:233) 13 at sun.net.www.http.HttpClient.New(HttpClient.java:306) 14 at sun.net.www.http.HttpClient.New(HttpClient.java:323) 15 at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:860) 16 at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:801) 17 at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:726) 18 at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1049) 19 at java.net.URL.openStream(URL.java:1010)
经检查发现是端口号不对，我项目是8022，而我写成了8080；
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补充：以上情况出现在服务器正常运行的情况下，如果服务器没有开启，也会出现这种问题。
不光是端口不对，也可能ip地址啊，请求的服务不对啊，等等。。。。。。。。。。。。。。。。。。。。。。