java - Ant 给出 _JAVA OPTIONS 消息

Question

我已在 Windows 8.1 上安装了 Apache Ant 1.8。

当我在控制台上运行 ant 命令时，它在屏幕上显示以下消息:
选择_JAVA_OPTIONS:-Djava.net.preferIPv4Stack=true

我无法找到此消息的原因。

附上屏幕截图供您引用。

请向我提供您对此的评论。还会影响ant的工作吗？

请忽略有关build.xml和“tools.jar”的错误。

Answer 1

When I am running the ant command on console, it is showing following message on screen: Picked up _JAVA_OPTIONS: -Djava.net.preferIPv4Stack=true

I am not able to find the reason of this message.

_JAVA_OPTIONS是一个特殊的环境变量。它将被 JVM 拾取。您正在设置java.net.preferIPv4Stack真正的意思是禁用IPV6。

export _JAVA_OPTIONS=-Djava.net.preferIPv4Stack=true

您可以使用以下方法实现相同的目的

System.setProperty("java.net.preferIPv4Stack" , "true");

通过应用程序中的代码级别。

IPv6-Related System Properties

On dual stack machines, system properties are provided for setting the preferred protocol stack—IPv4 or IPv6—as well as the preferred address family types—inet4 or inet6.

IPv6 stack is preferred by default, since on a dual-stack machine IPv6 socket can talk to both IPv4 and IPv6 peers.

This setting can be changed through the java.net.preferIPv4Stack=<true|false> system property.

By default, we would prefer IPv4 addresses over IPv6 addresses, i.e., when querying the name service (e.g., DNS service), we would return Ipv4 addresses ahead of IPv6 addresses.

在此处查看有关 Networking IPv6 User Guide for JDK/JRE 5.0 的信息.

顺便说一句，这不对您的错误负责。从您的错误消息来看，没有 build.xml看来是在目录中的文件。