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();
                    }
                }
            }
        }
    };