java运行shell脚本方法示例

2019-11-26 15:51:54

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现在通过CommandHelper.execute方法可以执行命令，该类实现

package javaapplication3;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
/**
 *
 * @author chenshu
 */
public class CommandHelper {
    //default time out, in millseconds
    public static int DEFAULT_TIMEOUT;
    public static final int DEFAULT_INTERVAL = 1000;
    public static long START;
    public static CommandResult exec(String command) throws IOException, InterruptedException {
        Process process = Runtime.getRuntime().exec(command);
        CommandResult commandResult = wait(process);
        if (process != null) {
process.destroy();
        }
        return commandResult;
    }
    private static boolean isOverTime() {
        return System.currentTimeMillis() - START >= DEFAULT_TIMEOUT;
    }
    private static CommandResult wait(Process process) throws InterruptedException, IOException {
        BufferedReader errorStreamReader = null;
        BufferedReader inputStreamReader = null;
        try {
errorStreamReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
inputStreamReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
//timeout control
START = System.currentTimeMillis();
boolean isFinished = false;
for (;;) {
if (isOverTime()) {
CommandResult result = new CommandResult();
result.setExitValue(CommandResult.EXIT_VALUE_TIMEOUT);
result.setOutput("Command process timeout");
return result;
}
if (isFinished) {
CommandResult result = new CommandResult();
result.setExitValue(process.waitFor());
//parse error info
if (errorStreamReader.ready()) {
StringBuilder buffer = new StringBuilder();
String line;
while ((line = errorStreamReader.readLine()) != null) {
buffer.append(line);
}
result.setError(buffer.toString());
}
//parse info
if (inputStreamReader.ready()) {
StringBuilder buffer = new StringBuilder();
String line;
while ((line = inputStreamReader.readLine()) != null) {
buffer.append(line);
}
result.setOutput(buffer.toString());
}
return result;
}
try {
isFinished = true;
process.exitValue();
} catch (IllegalThreadStateException e) {
// process hasn't finished yet
isFinished = false;
Thread.sleep(DEFAULT_INTERVAL);
}
}
        } finally {
if (errorStreamReader != null) {
try {
errorStreamReader.close();
} catch (IOException e) {
}
}
if (inputStreamReader != null) {
try {
inputStreamReader.close();
} catch (IOException e) {
}
}
        }
    }
}

CommandHelper类使用了CommandResult对象输出结果错误信息。该类实现

复制代码代码如下:

package javaapplication3;
/**
*
* @author chenshu
*/
public class CommandResult {
    public static final int EXIT_VALUE_TIMEOUT=-1;
    private String output;
    void setOutput(String error) {
        output=error;
    }
    String getOutput(){
        return output;
    }
    int exitValue;
    void setExitValue(int value) {
        exitValue=value;
    }
    int getExitValue(){
        return exitValue;
    }
    private String error;
    /**
     * @return the error
     */
    public String getError() {
        return error;
    }
    /**
     * @param error the error to set
     */
    public void setError(String error) {
        this.error = error;
    }
}

现在看看调用代码的演示（main函数接受一个超时参数）：

复制代码代码如下:

public static void main(String[] args) {
        try {
int timeout = Integer.parseInt(args[0]);
CommandHelper.DEFAULT_TIMEOUT = timeout;
CommandResult result = CommandHelper.exec("mkdir testdir");
if (result != null) {
System.out.println("Output:" + result.getOutput());
System.out.println("Error:" + result.getError());
}
        } catch (IOException ex) {
System.out.println("IOException:" + ex.getLocalizedMessage());
        } catch (InterruptedException ex) {
System.out.println("InterruptedException:" + ex.getLocalizedMessage());
        }
    }

结果会创建一个testdir目录。
我尝试用这种方法创建通过ssh登录到远程机器，遇到两个问题：
1）如果希望没有人机对话方式，则需要使用命令sshpass -p password ssh user@targetIP 'command'
2) 在NetBeans上直接运行工程是不行的，因为权限不够,需要在终端里运行java javaapplication3.Main
3) 很多命令不能运行，只有如pwd等命令可以运行，原因还不清楚，最好改用Ganymed SSH-2库或者其他类似Java库，我会在下一篇文章中介绍如何使用。

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