Java commons-exec 执行外部命令

java commons exec shell process

Java创建子进程(Process)执行外部命令底层的方法是new ProcessBuilder().start()或Runtime.getRuntime().exec()。

Apache commons-exec对底层进行封装，提供了更加详细的设置和监控方法。

pom.xml

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-exec</artifactId>
    <version>1.3</version>
</dependency>

CmdHelper.java

import java.io.IOException;
import java.io.OutputStream;
import java.util.concurrent.CompletableFuture;
import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteWatchdog;
import org.apache.commons.exec.PumpStreamHandler;
import org.apache.commons.exec.ShutdownHookProcessDestroyer;
public class CmdHelper {
    /**
     * 执行外部命令，等待返回结果
     * 
     * @param commandLine: 命令行
     * @param out:         输出流，为空默认标准输出
     * @param timeout:     超时，不大于0则不限超时
     * @return CmdHandler based on DefaultExecuteResultHandler
     */
    public static CmdHandler run(CommandLine commandLine, OutputStream out, long timeout) {
        PumpStreamHandler pumpStreamHandler = null;
        if (null == out) {
            pumpStreamHandler = new PumpStreamHandler();
        } else {
            pumpStreamHandler = new PumpStreamHandler(out);
        }
        DefaultExecutor executor = new DefaultExecutor();
        CmdHandler cmdHandler = new CmdHandler(executor);
        executor.setStreamHandler(pumpStreamHandler);
        ShutdownHookProcessDestroyer processDestroyer = new ShutdownHookProcessDestroyer();
        executor.setProcessDestroyer(processDestroyer);// 随主进程退出
        if (timeout <= 0) {
            timeout = ExecuteWatchdog.INFINITE_TIMEOUT;
        }
        ExecuteWatchdog watchdog = new ExecuteWatchdog(timeout);
        executor.setWatchdog(watchdog);// 控制超时
        try {
            executor.execute(commandLine, cmdHandler);
            cmdHandler.waitFor();// 等待返回结果
        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        }
        return cmdHandler;
    }
    /**
     * 异步执行外部命令
     * 
     * @param commandLine: 命令行
     * @param out:         输出流，为空默认标准输出
     * @param timeout:     超时，不大于0则不限超时
     * @return CompletableFuture<CmdHandler>
     */
    public static CompletableFuture<CmdHandler> exec(CommandLine commandLine, OutputStream out, long timeout) {
        CompletableFuture<CmdHandler> cf = new CompletableFuture<>();
        PumpStreamHandler pumpStreamHandler = null;
        if (null == out) {
            pumpStreamHandler = new PumpStreamHandler();
        } else {
            pumpStreamHandler = new PumpStreamHandler(out);
        }
        DefaultExecutor executor = new DefaultExecutor();
        CmdHandler cmdHandler = new CmdHandler(executor);
        cmdHandler.setCallback(() -> {
            cf.complete(cmdHandler);// 执行完成后回调
        });
        executor.setStreamHandler(pumpStreamHandler);
        ShutdownHookProcessDestroyer processDestroyer = new ShutdownHookProcessDestroyer();
        executor.setProcessDestroyer(processDestroyer);// 随主进程退出
        if (timeout <= 0) {
            timeout = ExecuteWatchdog.INFINITE_TIMEOUT;
        }
        ExecuteWatchdog watchdog = new ExecuteWatchdog(timeout);
        executor.setWatchdog(watchdog);// 控制超时
        try {
            executor.execute(commandLine, cmdHandler);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return cf;
    }
    public static void main(String[] args) throws InterruptedException {
        CommandLine command = CommandLine.parse("ping 127.0.0.1 -t");
        // 测试同步执行
        CmdHandler result = CmdHelper.run(command, null, 3000);
        System.out.println(result.resultString());
        // 测试异步执行
        CmdHelper.exec(command, null, 0).thenAccept(cmdHandler -> {
            System.out.println(cmdHandler.resultString());
        });
    }
}

CmdHandler.java

import org.apache.commons.exec.DefaultExecuteResultHandler;
import org.apache.commons.exec.ExecuteException;
import org.apache.commons.exec.ExecuteWatchdog;
import org.apache.commons.exec.Executor;
public class CmdHandler extends DefaultExecuteResultHandler {
    Executor executor;
    Runnable callback;
    public CmdHandler(Executor executor) {
        this.executor = executor;
    }
    public void setCallback(Runnable callback) {
        this.callback = callback;
    }
    public Executor getExecutor() {
        return this.executor;
    }
    public ExecuteWatchdog getWatchdog() {
        if (this.executor == null) return null;
        return this.executor.getWatchdog();
    }
    public String resultString() {
        String retMsg = "complete";
        if (this.getException() != null) {
            ExecuteWatchdog watchdog = this.getWatchdog();
            if (watchdog != null && watchdog.killedProcess()) {
                retMsg = "timeout";
            } else {
                retMsg = this.getException().getMessage();
            }
        }
        return this.getExitValue() + ":" + retMsg;
    }
    @Override
    public void onProcessComplete(int exitValue) {
        super.onProcessComplete(exitValue);
        if (callback != null) {
            callback.run();
        }
    }
    @Override
    public void onProcessFailed(ExecuteException e) {
        super.onProcessFailed(e);
        if (callback != null) {
            callback.run();
        }
    }
}

参考

1. https://www.cnblogs.com/kingcucumber/p/3180146.html
2. https://www.jianshu.com/p/73aaec23009d