我在使用Apache Commons Exec库更改PATH环境变量以指向我的目标目录中创建的Python virtualenv时遇到了一些困难。Apache Commons Exec更改PATH并执行virtualenv的点
理想情况下,我想要的东西等同于激活Python virtualenv,但在Java中。据我所知,执行此操作的最佳方法是更改环境变量,以便在我的othervenv
(这是我主要使用的另一个virtualenv)之前发现它的pip和python可执行文件。
我有我的PluginUtils
类此方法:
public static String callAndGetOutput(CommandLine commandLine, Map<String, String> environment) throws IOException
{
CollectingLogOutputStream outputStream = new CollectingLogOutputStream();
Executor executor = new DefaultExecutor();
DefaultExecuteResultHandler resultHandler = new DefaultExecuteResultHandler();
PumpStreamHandler streamHandler = new PumpStreamHandler(outputStream);
executor.setStreamHandler(streamHandler);
executor.execute(commandLine, environment, resultHandler);
try
{
// Wait for the subprocess to finish.
resultHandler.waitFor();
}
catch(InterruptedException e)
{
throw new IOException(e);
}
return outputStream.getOuput();
}
,然后将该类调用此方法。
import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.environment.EnvironmentUtils;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Map;
public class Example
{
public void run() throws Exception
{
Map<String, String> env = EnvironmentUtils.getProcEnvironment();
// env.forEach((k,v) -> System.out.println(k + "=" + v));
System.out.println(PluginUtilities.callAndGetOutput(CommandLine.parse("which python"), env));
System.out.println(PluginUtilities.callAndGetOutput(CommandLine.parse("which pip"), env));
Path venvDir = Paths.get("", "target", "testvenv");
Path venvBin = venvDir.resolve("bin");
assert(Files.isDirectory(venvDir));
assert(Files.isDirectory(venvBin));
env.put("PATH", venvBin.toAbsolutePath().toString()+ File.pathSeparator +env.get("PATH"));
env.put("VIRTUAL_ENV", venvDir.toAbsolutePath().toString());
// env.forEach((k,v) -> System.out.println(k + "=" + v));
System.out.println(PluginUtilities.callAndGetOutput(CommandLine.parse("which python"), env));
System.out.println(PluginUtilities.callAndGetOutput(CommandLine.parse("which pip"), env));
Path venvPip = venvBin.resolve("pip");
System.out.println(PluginUtilities.callAndGetOutput(CommandLine.parse("pip install jinja2"), env));
}
public static void main(String[] args) throws Exception
{
Example example = new Example();
example.run();
}
}
这样做的输出如下:
/home/lucas/.virtualenvs/othervenv/bin/python
/home/lucas/.virtualenvs/othervenv/bin/pip
/home/lucas/projects/myproject/mymodule/target/testvenv/bin/python
/home/lucas/projects/myproject/mymodule/target/testvenv/bin/pip
Requirement already satisfied: jinja2 in /home/lucas/.virtualenvs/othervenv/lib/python2.7/site-packages
Requirement already satisfied: MarkupSafe in /home/lucas/.virtualenvs/othervenv/lib/python2.7/site-packages (from jinja2)
我很困惑,为什么在运行pip
which pip
将返回正确点子可执行文件调用不正确的可执行文件。我能够直接使用venvPip
来安装jinja2,但我想避免将绝对路径传递给pip,而是让它在PATH上被发现。
我在想这可能是一个竞争条件,但我增加了DefaultExecuteResultHandler
所以所有的子进程调用是同步的,这似乎没有帮助。