ProcessBuilder 或 Runtime 类从哪里获取环境变量？

Question

这个link:Understanding Java Process and Java ProcessBuilder有一句话说用exec方法创建的进程不拥有控制台

如果我从 java 调用 python 脚本，进程从哪里获取环境变量？

如何 manipulate/add/remove Java 进程 class 使用的环境变量？

Answer 1

您可以使用ProcessBuilder.environment()方法获取Map的环境变量。

ProcessBuilder 文档指出：

Returns a string map view of this process builder's environment. Whenever a process builder is created, the environment is initialized to a copy of the current process environment (see System.getenv()). Subprocesses subsequently started by this object's start() method will use this map as their environment.

使用返回的映射，您可以设置您自己的自定义环境变量，您启动的进程将使用这些变量。

下面的示例片段演示了使用 ProcessBuilder API:

设置环境变量

public static void main(String[] args) throws Exception {
     ProcessBuilder pb =
                new ProcessBuilder("cmd.exe", "/C", "echo", "%JAVA_HOME%");
     Map<String, String> env = pb.environment();
     env.put("JAVA_HOME", "c/User/Programs/JDK...");
     Process p = pb.start();
     BufferedReader br  = new BufferedReader(new InputStreamReader(p.getInputStream()));
     String line = "";
     while((line=br.readLine()) != null){
         System.out.println(line);
     }
     try {
         int exitValue = p.waitFor();
         System.out.println("\n\nExit Value is " + exitValue);
     } catch (InterruptedException e) {
            e.printStackTrace();
     }
}

ProcessBuilder 或 Runtime 类从哪里获取环境变量？

Where does ProcessBuilder or Runtime classes get the environment variables from?

java

windows

process

processbuilder

ProcessBuilder 或 Runtime 类 从哪里获取环境变量？

Where does ProcessBuilder or Runtime classes get the environment variables from?

java

windows

process

processbuilder

ProcessBuilder 或 Runtime 类从哪里获取环境变量？