Java Shell命令调用及交互算法封装

发表于 | 分类于 |

简介

Java调用Shell命令运行子进程的方式如下代码：

1
2
3
4
5
6
ProcessBuilder processBuilder = new ProcessBuilder("pwd");
Process process = processBuilder.start();
if (process.waitFor(timeout, TimeUnit.MILLISECONDS)) {
    status = process.exitValue();
    System.out.println(status);
}

现在需要在子进程运行过程中，实时收集子进程输出流的行输出，因此需要设计算法实现该功能。

设计

采用监听模式，调用子进程执行Shell命令同时注册监听器
子进程行输出将以实时调用监听器对象传参的方式传递给监听器。

原始程序流程图：
image

核心代码片段

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
public static int execute(String command, String directory, Long timeout, final Communicator... communicators) throws CommandTimeoutException {
    final ProcessBuilder processBuilder = new ProcessBuilder(command);
    if (directory != null) {
        File workDir = new File(directory);
        if (workDir.exists() && workDir.isDirectory()) {
            processBuilder.directory(workDir);
        }
    }
    processBuilder.redirectErrorStream(true);
    int status = -1;
    try {
        final Process process = processBuilder.start();
        if (communicators != null && communicators.length > 0) {
            communicatorExecutor.submit(() -> {
                BufferedReader reader = null;
                try {
                    InputStream inputStream = process.getInputStream();
                    if (inputStream == null) {
                        return;
                    }
                    reader = new BufferedReader(new InputStreamReader(inputStream));
                    String line;
                    while ((line = reader.readLine()) != null) {
                        for (Communicator communicator : communicators) {
                            communicator.onMessage(line, process);
                        }
                    }
                } catch (Exception e) {
                    logger.warn(e.getMessage(), e);
                } finally {
                    if (reader != null) {
                        try {
                            reader.close();
                        } catch (Exception e) {
                            logger.warn(e.getMessage(), e);
                        }
                    }
                }
            });
        }
        if (timeout == null || timeout <= 0) {
            status = process.waitFor();
        } else {
            if (!process.waitFor(timeout, TimeUnit.MILLISECONDS)) {
                throw new CommandTimeoutException(String.format("Command execute timeout, timeout: %s, command: %s", timeout, command));
            } else {
                status = process.exitValue();
            }
        }
        TimeUnit.MILLISECONDS.sleep(100);
    } catch (Exception e) {
        logger.warn(e.getMessage(), e);
        if (e instanceof CommandTimeoutException) {
            throw (CommandTimeoutException) e;
        }
    }
    return status;
}

说明：

方法参数 说明
command Shell命令
directory 执行命令的目录路径
timeout 命令执行等待时间，null则一直等待直到命令执行结束
communicators 交互对象列表，子进程运行输出监听器

用法示例

用法

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

@Test
public void simpleTest() {
    try {
        int exitValue = ShellExecutor.execute(
                "./test.sh",
                System.getProperty("user.dir")+"/scripts",
                null,
                (message, process) -> System.out.println(message)
        );
        System.out.println("exitValue: " + exitValue);
    } catch (ShellExecutor.CommandTimeoutException e) {
        System.out.println(e.getMessage());
    }
}

Shell脚本 test.sh 如下：

1
2
3
4
5
6
7
8
9
10
11
12
13
#!/bin/bash

source /etc/profile

i=0
while((${i} < 20))
do
    echo "Printout success, index: ${i}"
    let "i++"
    sleep 2
done

exit 0

结果输出

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Printout success, index: 0
Printout success, index: 1
Printout success, index: 2
Printout success, index: 3
Printout success, index: 4
Printout success, index: 5
Printout success, index: 6
Printout success, index: 7
Printout success, index: 8
Printout success, index: 9
Printout success, index: 10
Printout success, index: 11
Printout success, index: 12
Printout success, index: 13
Printout success, index: 14
Printout success, index: 15
Printout success, index: 16
Printout success, index: 17
Printout success, index: 18
Printout success, index: 19
exitValue: 0

代码仓库

https://github.com/johnsonmoon/ShellExecutor.git