Java 可以通过 Runtime 调用Linux命令，形式如下：
Runtime.getRuntime().exec(command)
但是这样执行时没有任何输出，因为调用 Runtime.exec 方法将产生一个本地的进程，并返回一个Process子类的实例
（注意：Runtime.getRuntime().exec（command）返回的是一个Process类的实例）该实例可用于控制进程或取得进程的相关信息。
由于调用 Runtime.exec 方法所创建的子进程没有自己的终端或控制台，因此该子进程的标准IO（如stdin,stdou,stderr）都通过 Process.getOutputStream()，Process.getInputStream()， Process.getErrorStream() 方法重定向给它的父进程了。
用户需要用这些stream来向子进程输入数据或获取子进程的输出，下面的代码可以取到 linux 命令的执行结果：
try {
String[] cmd = new String[]{”/bin/sh”, “-c”, ” ls “};
Process ps = Runtime.getRuntime().exec(cmd);
BufferedReader br = new BufferedReader(new InputStreamReader(ps.getInputStream()));
StringBuffer sb = new StringBuffer();
String line;
while ((line = br.readLine()) != null) {
sb.append(line).append(”\n”);
}
String result = sb.toString();
System.out.println(result);
} catch (Exception e) {
e.printStackTrace();
}
package com.cisco.learning;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
public class Ys {
public static void main(String[] args) throws IOException {
Process exec = Runtime.getRuntime().exec("notepad");
InputStream inputStream = exec.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
StringBuilder stringBuilder = new StringBuilder(10);
try {
String tmp;
while ((tmp = bufferedReader.readLine()) != null) {
stringBuilder.append(tmp);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
bufferedReader.close();
}
System.out.println(stringBuilder.toString());
}
}
package com.cisco.learning;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
public class Ys {
public static void main(String[] args) throws IOException {
Process exec = Runtime.getRuntime().exec("notepad");
InputStream inputStream = exec.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
StringBuilder stringBuilder = new StringBuilder(10);
try {
String tmp;
while ((tmp = bufferedReader.readLine()) != null) {
stringBuilder.append(tmp);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
bufferedReader.close();
}
System.out.println(stringBuilder.toString());
}
}