Java ProcessBuilder示例

布满荆棘的人生 2023-02-15 05:10 21阅读 0赞

在Java中，我们可以使用`ProcessBuilder`轻松调用外部命令：

ProcessBuilder processBuilder = new ProcessBuilder();
    
    	// -- Linux --
    
    	// Run a shell command
    	processBuilder.command("bash", "-c", "ls /home/mkyong/");
    
    	// Run a shell script
    	processBuilder.command("path/to/hello.sh");
    
    	// -- Windows --
    
    	// Run a command
    	processBuilder.command("cmd.exe", "/c", "dir C:\\Users\\mkyong");
    
    	// Run a bat file
    	processBuilder.command("C:\\Users\\mkyong\\hello.bat");
    
    	Process process = processBuilder.start();

## 1.平 ##

1.1运行外部ping命令对网站进行ping操作3次，并显示输出信息。

ProcessBuilderExample1.java

package com.mkyong.process;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    
    public class ProcessBuilderExample1 {
    
        public static void main(String[] args) {
    
            ProcessBuilder processBuilder = new ProcessBuilder();
    
            // Run this on Windows, cmd, /c = terminate after this run
            processBuilder.command("cmd.exe", "/c", "ping -n 3 google.com");
    
            try {
    
                Process process = processBuilder.start();
    
    			// blocked :(
                BufferedReader reader =
                        new BufferedReader(new InputStreamReader(process.getInputStream()));
    
                String line;
                while ((line = reader.readLine()) != null) {
                    System.out.println(line);
                }
    
                int exitCode = process.waitFor();
                System.out.println("\nExited with error code : " + exitCode);
    
            } catch (IOException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
    
        }
    
    }

输出量

Pinging google.com [172.217.166.142] with 32 bytes of data:
    Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
    Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
    Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
    
    Ping statistics for 172.217.166.142:
        Packets: Sent = 3, Received = 3, Lost = 0 (0% loss),
    Approximate round trip times in milli-seconds:
        Minimum = 10ms, Maximum = 10ms, Average = 10ms
    
    Exited with error code : 0

## 2. Ping +线程 ##

在上面的示例1.1中， `process.getInputStream`是“ blocking”，最好为读取过程启动一个新的Thread，这样它就不会阻止其他任务。

ProcessBuilderExample2.java

package com.mkyong.process;
    
    import java.io.BufferedReader;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.util.List;
    import java.util.concurrent.*;
    import java.util.stream.Collectors;
    
    public class ProcessBuilderExample2 {
    
        public static void main(String[] args) {
    
            ExecutorService pool = Executors.newSingleThreadExecutor();
    
            ProcessBuilder processBuilder = new ProcessBuilder();
    
            // Run this on Windows, cmd, /c = terminate after this run
            processBuilder.command("cmd.exe", "/c", "ping -n 3 google.com");
    
            try {
    
                Process process = processBuilder.start();
    
                System.out.println("process ping...");
                ProcessReadTask task = new ProcessReadTask(process.getInputStream());
                Future<list<string>> future = pool.submit(task);
    
                // no block, can do other tasks here
                System.out.println("process task1...");
                System.out.println("process task2...");
    
                List<string> result = future.get(5, TimeUnit.SECONDS);
                for (String s : result) {
                    System.out.println(s);
                }
    
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                pool.shutdown();
            }
        }
    
        private static class ProcessReadTask implements Callable<list<string>> {
    
            private InputStream inputStream;
    
            public ProcessReadTask(InputStream inputStream) {
                this.inputStream = inputStream;
            }
    
            @Override
            public List<string> call() {
                return new BufferedReader(new InputStreamReader(inputStream))
    				.lines()
    				.collect(Collectors.toList());
            }
        }
    
    }

输出量

process ping...
    process task1...
    process task2...
    
    Pinging google.com [172.217.166.142] with 32 bytes of data:
    Reply from 172.217.166.142: bytes=32 time=11ms TTL=55
    Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
    Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
    
    Ping statistics for 172.217.166.142:
        Packets: Sent = 3, Received = 3, Lost = 0 (0% loss),
    Approximate round trip times in milli-seconds:
        Minimum = 10ms, Maximum = 11ms, Average = 10ms

## 3.更改目录 ##

3.1转到目录`C:\\users`并运行external `dir`命令列出所有文件。

ProcessBuilderExample3.java

package com.mkyong.process;
    
    import java.io.BufferedReader;
    import java.io.File;
    import java.io.IOException;
    import java.io.InputStreamReader;
    
    public class ProcessBuilderExample3 {
    
        public static void main(String[] args) {
    
            ProcessBuilder processBuilder = new ProcessBuilder();
    
            processBuilder.command("cmd.exe", "/c", "dir");
            processBuilder.directory(new File("C:\\users"));
    
            // can also run the java file like this
            // processBuilder.command("java", "Hello");
    
            try {
    
                Process process = processBuilder.start();
    
                BufferedReader reader =
                        new BufferedReader(new InputStreamReader(process.getInputStream()));
    
                String line;
                while ((line = reader.readLine()) != null) {
                    System.out.println(line);
                }
    
                int exitCode = process.waitFor();
                System.out.println("\nExited with error code : " + exitCode);
    
            } catch (IOException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
    
        }
    
    }

输出量

Volume in drive C has no label.
     Volume Serial Number is CE5B-B4C5
    
     Directory of C:\users
    
    //...

## 参考文献 ##

1.  [Microsoft系统错误代码（0-499）][Microsoft_0-499]
2.  [如何从Java执行Shell命令][Java_Shell]
3.  [Java文档– ProcessBuilder][Java_ ProcessBuilder]
4.  [cmd / C是什么意思？][cmd _ C]

标签： [可调用的][Link 1] [外部命令][Link 2] [java][] [进程][Link 3] [shell命令][shell] [线程][Link 4]

> 翻译自: [https://mkyong.com/java/java-processbuilder-examples/][https_mkyong.com_java_java-processbuilder-examples]

[Microsoft_0-499]: https://docs.microsoft.com/en-us/windows/desktop/debug/system-error-codes--0-499-
[Java_Shell]: https://www.mkyong.com/java/how-to-execute-shell-command-from-java/
[Java_ ProcessBuilder]: https://docs.oracle.com/javase/8/docs/api/java/lang/ProcessBuilder.html
[cmd _ C]: https://stackoverflow.com/questions/515309/what-does-cmd-c-mean
[Link 1]: https://mkyong.com/tag/callable/
[Link 2]: https://mkyong.com/tag/external-command/
[java]: https://mkyong.com/tag/java/
[Link 3]: https://mkyong.com/tag/process/
[shell]: https://mkyong.com/tag/shell-command/
[Link 4]: https://mkyong.com/tag/thread/
[https_mkyong.com_java_java-processbuilder-examples]: https://mkyong.com/java/java-processbuilder-examples/