Java调用命令行

Runtime.exec() 不等同于直接执行command line命令！

啊，我算是在这里吃了苦头了。Runtime.exec()很有局限性，对有些命令不能直接把command line里的内容当作String参数传给exec().

比如重定向等命令。举个例子:

javap -l xxx > output.txt

这时要用到exec的第二种重载，即input 参数为String[]:

Process p = Runtime.getRuntime().exec(new String[]{“/bin/sh”,”-c”,”javap -l xxx > output.txt”});

import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.util.ArrayList;
import java.util.List;

public class test{
/**
* 运行shell脚本
* @param shell 需要运行的shell脚本
*/
public static void execShell(String shell){

try {
Runtime rt = Runtime.getRuntime();
rt.exec(shell);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 运行shell
*
* @param shStr
*            需要执行的shell
* @return
* @throws IOException
*/
public static List runShell(String shStr) throws Exception {
List<String> strList = new ArrayList();

Process process;
process = Runtime.getRuntime().exec(new String[]{"/bin/sh","-c",shStr},null,null);
//process = Runtime.getRuntime().exec(shStr);
InputStreamReader ir = new InputStreamReader(process
.getInputStream());
LineNumberReader input = new LineNumberReader(ir);
String line;
process.waitFor();
while ((line = input.readLine()) != null){
System.out.println(line);
strList.add(line);
}

return strList;
}
public static void main(String []arge)throws Exception {

test t=new test();
t.runShell("/home/ubuntu/soft/tomcat/bin/startup.sh")
}

获得输出值：

执行命令行获取返回值：

方法一

Process p = Runtime.getRuntime().exec("javac");
InputStream is = p.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
String line;
while((line = reader.readLine())!= null){
System.out.println(line);
}
p.waitFor();
is.close();
reader.close();
p.destroy();

方法二

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

public class TestCmd {
public static void main(String[] args) {
java.lang.Process process = null;
try {
process = Runtime.getRuntime().exec("net user");
ByteArrayOutputStream resultOutStream = new ByteArrayOutputStream();
InputStream errorInStream = new BufferedInputStream(
process.getErrorStream());
InputStream processInStream = new BufferedInputStream(
process.getInputStream());
int num = 0;
byte[] bs = new byte[1024];
while ((num = errorInStream.read(bs)) != -1) {
resultOutStream.write(bs, 0, num);
}
while ((num = processInStream.read(bs)) != -1) {
resultOutStream.write(bs, 0, num);
}
String result = new String(resultOutStream.toByteArray());
System.out.println(result);
errorInStream.close();
errorInStream = null;
processInStream.close();
processInStream = null;
resultOutStream.close();
resultOutStream = null;
} catch (IOException e) {
e.printStackTrace();
} finally {
if (process != null)
process.destroy();
process = null;
}
}
}

附项目实战代码：

DataOutputStream os = null;
private Process process = null;
private Handler mCaptureHanlder = new Handler(new Handler.Callback() {

@Override
public boolean handleMessage(Message msg) {
return false;
}
});

// 开始抓包
private Runnable mCaptureRunnable = new Runnable() {
public void run() {
if (!TextUtils.isEmpty(ForkConstants.path)) {
String commandPath = mContext.getFilesDir().getAbsolutePath() + "/tcpdump";
String permissionCmd = "chmod 777 " + commandPath;

try {
Runtime.getRuntime().exec(permissionCmd);
process = Runtime.getRuntime().exec("su");
os = new DataOutputStream(process.getOutputStream());
os.writeBytes(commandPath + " " + ForkConstants.parameters.trim() + " -w " + ForkConstants.path + "\n");

} catch (Exception e) {
e.printStackTrace();
}
}
}
};

// 停止抓包
private Runnable mStopRunnable = new Runnable() {
public void run() {
if (!TextUtils.isEmpty(ForkConstants.path)) {
try {
os.writeBytes("kill $(ps | grep tcpdump | tr -s ' ' | cut -d ' ' -f2)\n");
os.writeBytes("killall tcpdump\n");
os.writeBytes("busybox kill $(ps | grep tcpdump | tr -s ' ' | cut -d ' ' -f2)\n");
os.writeBytes("busybox killall tcpdump\n");
os.writeBytes("exit\n");
os.flush();
os.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
process.getInputStream().close();
process.getOutputStream().close();
process.destroy();
process = null;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
};