很多时候,Java应用程序需要连接到Internet。最常见的例子发生在读取XML文件并需要下载其模式时。

我在代理服务器后面。如何将JVM设置为使用代理?


当前回答

可以将代理服务器的一些属性设置为jvm参数

-Dhttp。proxyPort=8080, proxyHost,等等。

但是如果你需要通过一个认证代理,你需要一个像下面这样的验证器:

ProxyAuthenticator.java

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

public class ProxyAuthenticator extends Authenticator {

    private String userName, password;

    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication(userName, password.toCharArray());
    }

    public ProxyAuthenticator(String userName, String password) {
        this.userName = userName;
        this.password = password;
    }
}

Example.java

    import java.net.Authenticator;
    import ProxyAuthenticator;

public class Example {

    public static void main(String[] args) {
        String username = System.getProperty("proxy.authentication.username");
        String password = System.getProperty("proxy.authentication.password");

                if (username != null && !username.equals("")) {
            Authenticator.setDefault(new ProxyAuthenticator(username, password));
        }

                // here your JVM will be authenticated

    }
}

根据这个回复: http://mail-archives.apache.org/mod_mbox/jakarta-jmeter-user/200208.mbox/%3C494FD350388AD511A9DD00025530F33102F1DC2C@MMSX006%3E

其他回答

从Java文档(不是javadoc API):

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

设置JVM标志http。proxyHost和http。在命令行上启动JVM时使用proxyPort。 这通常是在shell脚本(Unix)或bat文件(Windows)中完成的。下面是Unix shell脚本的示例:

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

当使用JBoss或WebLogic等容器时,我的解决方案是编辑供应商提供的启动脚本。

许多开发人员都熟悉Java API (javadocs),但很多时候忽略了文档的其余部分。它包含许多有趣的信息:http://download.oracle.com/javase/6/docs/technotes/guides/


更新:如果您不想使用代理来解析一些本地/内网主机,请查看来自@Tomalak的评论:

不要忘记http。nonProxyHosts财产!

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

将usesystemagents属性设置为true。例如,您可以通过JAVA_TOOL_OPTIONS环境变量来设置它。例如,在Ubuntu中,你可以在.bashrc中添加以下代码行:

export JAVA_TOOL_OPTIONS+=" - djava.net.usesystemagents =true"

在连接到代理后面的URL之前添加此选项。

System.getProperties().put("http.proxyHost", "someProxyURL");
System.getProperties().put("http.proxyPort", "someProxyPort");
System.getProperties().put("http.proxyUser", "someUserName");
System.getProperties().put("http.proxyPassword", "somePassword");

You can utilize the http.proxy* JVM variables if you're within a standalone JVM but you SHOULD NOT modify their startup scripts and/or do this within your application server (except maybe jboss or tomcat). Instead you should utilize the JAVA Proxy API (not System.setProperty) or utilize the vendor's own configuration options. Both WebSphere and WebLogic have very defined ways of setting up the proxies that are far more powerful than the J2SE one. Additionally, for WebSphere and WebLogic you will likely break your application server in little ways by overriding the startup scripts (particularly the server's interop processes as you might be telling them to use your proxy as well...).

最近,我发现了允许JVM使用浏览器代理设置的方法。你需要做的是将${java.home}/lib/deploy.jar添加到你的项目中,并像下面这样初始化库:

import com.sun.deploy.net.proxy.DeployProxySelector;
import com.sun.deploy.services.PlatformType;
import com.sun.deploy.services.ServiceManager;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public abstract class ExtendedProxyManager {

    private static final Log logger = LogFactory.getLog(ExtendedProxyManager.class);

    /**
     * After calling this method, proxy settings can be magically retrieved from default browser settings.
     */
    public static boolean init() {
        logger.debug("Init started");

        // Initialization code was taken from com.sun.deploy.ClientContainer:
        ServiceManager
                .setService(System.getProperty("os.name").toLowerCase().indexOf("windows") != -1 ? PlatformType.STANDALONE_TIGER_WIN32
                        : PlatformType.STANDALONE_TIGER_UNIX);

        try {
            // This will call ProxySelector.setDefault():
            DeployProxySelector.reset();
        } catch (Throwable throwable) {
            logger.error("Unable to initialize extended dynamic browser proxy settings support.", throwable);

            return false;
        }

        return true;
    }
}

之后,可以通过java.net.ProxySelector将代理设置提供给Java API。

这种方法的唯一问题是你需要在bootclasspath中使用deploy.jar启动JVM,例如java -Xbootclasspath/a:"%JAVA_HOME%\jre\lib\deploy.jar" -jar my.jar。如果有人知道如何克服这个限制,请告诉我。