How do I set the proxy to be used by the JVM

Many times, a Java app needs to connect to the Internet. The most common example happens when it is reading an XML file and needs to download its schema.

I am behind a proxy server. How can I set my JVM to use the proxy ?

Solution 1:

From the Java documentation (not the javadoc API):

http://download.oracle.com/javase/6/docs/technotes/guides/net/proxies.html

Set the JVM flags http.proxyHost and http.proxyPort when starting your JVM on the command line. This is usually done in a shell script (in Unix) or bat file (in Windows). Here's the example with the Unix shell script:

JAVA_FLAGS=-Dhttp.proxyHost=10.0.0.100 -Dhttp.proxyPort=8800
java ${JAVA_FLAGS} ...

When using containers such as JBoss or WebLogic, my solution is to edit the start-up scripts supplied by the vendor.

Many developers are familiar with the Java API (javadocs), but many times the rest of the documentation is overlooked. It contains a lot of interesting information: http://download.oracle.com/javase/6/docs/technotes/guides/

Update : If you do not want to use proxy to resolve some local/intranet hosts, check out the comment from @Tomalak:

Also don't forget the http.nonProxyHosts property!

-Dhttp.nonProxyHosts="localhost|127.0.0.1|10.*.*.*|*.foo.com‌​|etc"

Solution 2:

To use the system proxy setup:

java -Djava.net.useSystemProxies=true ...

Or programatically:

System.setProperty("java.net.useSystemProxies", "true");

Source: http://docs.oracle.com/javase/7/docs/api/java/net/doc-files/net-properties.html

Solution 3:

To set an HTTP/HTTPS and/or SOCKS proxy programmatically:

...

public void setProxy() {
    if (isUseHTTPProxy()) {
        // HTTP/HTTPS Proxy
        System.setProperty("http.proxyHost", getHTTPHost());
        System.setProperty("http.proxyPort", getHTTPPort());
        System.setProperty("https.proxyHost", getHTTPHost());
        System.setProperty("https.proxyPort", getHTTPPort());
        if (isUseHTTPAuth()) {
            String encoded = new String(Base64.encodeBase64((getHTTPUsername() + ":" + getHTTPPassword()).getBytes()));
            con.setRequestProperty("Proxy-Authorization", "Basic " + encoded);
            Authenticator.setDefault(new ProxyAuth(getHTTPUsername(), getHTTPPassword()));
        }
    }
    if (isUseSOCKSProxy()) {
        // SOCKS Proxy
        System.setProperty("socksProxyHost", getSOCKSHost());
        System.setProperty("socksProxyPort", getSOCKSPort());
        if (isUseSOCKSAuth()) {
            System.setProperty("java.net.socks.username", getSOCKSUsername());
            System.setProperty("java.net.socks.password", getSOCKSPassword());
            Authenticator.setDefault(new ProxyAuth(getSOCKSUsername(), getSOCKSPassword()));
        }
    }
}

...

public class ProxyAuth extends Authenticator {
    private PasswordAuthentication auth;

    private ProxyAuth(String user, String password) {
        auth = new PasswordAuthentication(user, password == null ? new char[]{} : password.toCharArray());
    }

    protected PasswordAuthentication getPasswordAuthentication() {
        return auth;
    }
}

...

Remember that HTTP proxies and SOCKS proxies operate at different levels in the network stack, so you can use one or the other or both.

Solution 4:

You can set those flags programmatically this way:

if (needsProxy()) {
    System.setProperty("http.proxyHost",getProxyHost());
    System.setProperty("http.proxyPort",getProxyPort());
} else {
    System.setProperty("http.proxyHost","");
    System.setProperty("http.proxyPort","");
}

Just return the right values from the methods needsProxy(), getProxyHost() and getProxyPort() and you can call this code snippet whenever you want.

Solution 5:

JVM uses the proxy to make HTTP calls

System.getProperties().put("http.proxyHost", "someProxyURL");
System.getProperties().put("http.proxyPort", "someProxyPort");

This may use user setting proxy

System.setProperty("java.net.useSystemProxies", "true");