Runtime.getRuntime().exec（)----记录日志案例

public Process exec(String command, String[] envp, File dir) throws IOException {
    if (command.length() == 0) throw new IllegalArgumentException("Empty command");
    StringTokenizer st = new StringTokenizer(command);
    String[] cmdarray = new String[st.countTokens()];
    for (int i = 0; st.hasMoreTokens(); i++)
        cmdarray[i] = st.nextToken();
    return exec(cmdarray, envp, dir);
}

从上面的代码，我们可以看出最终调用的代码都是：exec(String[] cmdArray,String envp,File  dir)。exec(String command)相当于exec(command,null,null)，exec(String[] cmdArray)相当于exec(cmdArray,null,null)。

    "javap -l xxx > output.txt"});

5.getOutputStream()：获取子进程的输出流

6.waitFor()：导致当前线程等待，如有必要，一直要等到由该 Process 对象表示的进程已经终止。如果已终止该子进程，此方法立即返回。如果没有终止该子进程，调用的线程将被阻塞，直到退出子进程，根据惯例，0 表示正常终止

对Runtime.getRuntime.exec()的了解可以参考博客：http://www.cnblogs.com/mingforyou/p/3551199.html

案列：实现Log中的日志显示(以对话框的形式演示，可以将输出日志保存到具体的文件中)

public class MainActivity extends Activity implements OnClickListener{
    Button conLog;
	/** Called when the activity is first created. */
    @Override 
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        conLog = (Button) findViewById(R.id.conLog);//通过id找到的按钮
        MyLog.isDebug = true;//debug模式开启
       conLog.setOnClickListener(this);
    }
	public void onClick(View v) {
		//按钮被点击到了，收集收集日志
		try {
			readLog();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	/**
	 * @author Danny QQ 858030348  
	 * @throws IOException 
	 * 
	 */
	private void readLog() throws IOException {
		MyLog.i("INFO", "start connectLog");
		StringBuffer sb = new StringBuffer();
		ArrayList<String> cmdLine = new ArrayList<String>();
		cmdLine.add("logcat");
		cmdLine.add("-d");//收集一次日志停止
		cmdLine.add("-s");//过滤
		cmdLine.add("INFO");
		System.out.println(cmdLine.toArray(new String[cmdLine.size()]));
		Process exec = Runtime.getRuntime().exec(cmdLine.toArray(new String[cmdLine.size()]));
		//获取执行命令后的输入流
		InputStream inputStream = exec.getInputStream();
		InputStreamReader buInputStreamReader = new InputStreamReader(inputStream);//装饰器模式
		BufferedReader bufferedReader = new BufferedReader(buInputStreamReader);//直接读字符串
		String str = null;
		while((str = bufferedReader.readLine())!=null){
			sb.append(str);//每读一行拼接到sb里面去
			sb.append("\n");//每一行一个换行符
		}
		//吐司
		Toast.makeText(this, sb.toString(), 1000).show();
	}
}

Runtime.getRuntime().exec（)----记录日志案例

原文：http://blog.csdn.net/itjavawfc/article/details/46667213