Java intellij Idea中的连接超时错误

我正在尝试使用HttpURLConnection发出一个简单的http请求。我收到此错误，连接超时。我正在使用intellij IDEA，并正确设置代理。在设置中检查连接，表示连接成功。可能出了什么问题？这是我的密码

import java.io.*;
import java.net.*;

/**
 * Created by admin on 22/8/15.
 */
public class Hello {
    public static void main(String [] args)
    {
        try
        {
            URL url = new URL("http://www.google.com");
            URLConnection urlConnection = url.openConnection();
            HttpURLConnection connection = null;
            if(urlConnection instanceof HttpURLConnection)
            {
                connection = (HttpURLConnection) urlConnection;
            }
            else
            {
                System.out.println("Please enter an HTTP URL.");
                return;
            }
            BufferedReader in = new BufferedReader(
                    new InputStreamReader(connection.getInputStream()));
            String urlString = "";
            String current;
            while((current = in.readLine()) != null)
            {
                urlString += current;
            }
            System.out.println(urlString);
        }catch(IOException e)
        {
            e.printStackTrace();
        }
    }
}

错误如下所示

java.net.ConnectException: Connection timed out
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
    at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
    at java.net.Socket.connect(Socket.java:529)
    at java.net.Socket.connect(Socket.java:478)
    at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:394)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:529)
    at sun.net.www.http.HttpClient.<init>(HttpClient.java:233)
    at sun.net.www.http.HttpClient.New(HttpClient.java:306)
    at sun.net.www.http.HttpClient.New(HttpClient.java:323)
    at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:860)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:801)
    at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:726)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1049)
    at Hello.main(Hello.java:24)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)

Process finished with exit code 0

---

创建两个同名的属性文件（proxy.properties）。使用包含以下内容的文件：

http.proxyHost=lotus
http.proxyPort=8080

http.proxyHost=
http.proxyPort=

。。。用于开发，并包含：

http.proxyHost=lotus
http.proxyPort=8080

http.proxyHost=
http.proxyPort=

应运至生产部

那么在你上面的班级里：

static Proxy getProxy() throws IOException {
    Properties proxyProperties = new Properties();
    InputStream inputStream = null;
    try {
        inputStream = Hello.getClass().getClassLoader().getResourceAsStream("proxy.properties");
        proxyProperties.load(inputStream);
    } finally {
        if(inputStream != null) {
            try {
                inputStream.close();
            } catch(IOException ioe) {
            }
        }
    }
    String proxyHost = proxyProperties.getProperty("http.proxyHost");
    if(proxyHost != null && proxyHost.length() > 0)) {
        String proxyPort = proxyProperties.getProperty("http.proxyPort");
        SocketAddress addr = new InetSocketAddress(proxyHost, Integer.parseInt(proxyPort));
        return new Proxy(Proxy.Type.HTTP, addr);
    }
    return null;
}

然后在您的主要方法中：

...
URL url = new URL("http://www.google.com");
URLConnection urlConnection;
Proxy = getProxy();
if(proxy != null) {
    urlConnection = url.openConnection(proxy);
} else {
    urlConnection = url.openConnection();
HttpURLConnection connection = null;
...

---

我不想在我的代码中使用代理，这对我来说是不可行的@RCI在我的IntelliJ 11上测试了你的代码，效果很好。是的，在我的代码中使用系统属性时效果很好。但是当从代码中删除这些行时，它就不起作用了@TimBiegeleisenWildcard imports是一种糟糕的做法，因为很难看到引用的类来自何处。然后，您无法查看它是来自同一个包还是来自库的类。若在包中有相同的名称，那个么无意中隐藏库类就更容易了。