[英]Executing a command in Java
我正在尝试编写一个可以从命令行执行vagrant
的Java
类:
import java.io.BufferedReader;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.util.List;
public class Hello {
public static void deploy() {
String path = System.getProperty("user.home") + "/ansible/solr/";
try {
String command = "vagrant up";
ProcessBuilder builder = new ProcessBuilder(command);
System.out.println("------------------------------------------------");
System.out.println("Executing " + command + " in directory " + path);
System.out.println("Current path: " + Paths.get(".").toAbsolutePath().normalize().toString());
builder.directory(new File(path));
Process child = builder.start();
watch(child);
System.out.println("------------------------------------------------");
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
}
private static void watch(final Process process) {
new Thread() {
@Override
public void run() {
BufferedReader input = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line = null;
try {
System.out.println("------------------------------------------------");
System.out.println("Executing Ansible");
while ((line = input.readLine()) != null) {
System.out.println(line);
}
System.out.println("------------------------------------------------");
} catch (IOException ex) {
System.out.println(ex.getMessage());
}
}
}.start();
}
public static void main(String[] args) {
deploy();
}
}
在/ansible/solr
目录中,我具有:
-rw-r--r-- 1 ubuntu staff 2.1K Sep 17 08:36 README.md
-rw-r--r-- 1 ubuntu staff 840B Sep 17 08:36 Vagrantfile
drwxr-xr-x 4 ubuntu staff 136B Sep 17 08:36 provisioning/
-rw-r--r-- 1 ubuntu staff 80B Sep 17 08:36 requirements.yml
并且目录/home/ubuntu/ansible/solr
显然存在。 当我执行上面的程序时,我得到:
------------------------------------------------
Executing vagrant up in directory /home/ubuntu/ansible/solr
Current path: /home/ubuntu
Cannot run program "vagrant up" (in directory "/home/ubuntu/ansible/solr"): error=2, No such file or directory
为什么我收到此错误?
根据ProcessBuilder的注释,您应该分离命令及其参数:
/**
* Constructs a process builder with the specified operating
* system program and arguments. This is a convenience
* constructor that sets the process builder's command to a string
* list containing the same strings as the {@code command}
* array, in the same order. It is not checked whether
* {@code command} corresponds to a valid operating system
* command.
*
* @param command a string array containing the program and its arguments
*/
public ProcessBuilder(String... command) {
this.command = new ArrayList<>(command.length);
for (String arg : command)
this.command.add(arg);
}
所以尝试:
ProcessBuilder builder = new ProcessBuilder("vagrant", "up");
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