一、Java调用Linux系统的命令非常简单

这是一个非常常用的调用方法示例：

1 publicString executeLinuxCmd(String cmd) {2 System.out.println("got cmd job :" +cmd);3 Runtime run =Runtime.getRuntime();4 try{5 Process process =run.exec(cmd);6 InputStream in =process.getInputStream();7 BufferedReader bs = new BufferedReader(new InputStreamReader(in));8 //System.out.println("[check] now size

"+bs.readLine());StringBuffer out = new StringBuffer();

byte[] b = new byte[8192];

for (int n; (n = in.read(b)) != -1;) {

out.append(new String(b, 0, n));

}

System.out.println("job result [" + out.toString() + "]");

14 in.close();15 //process.waitFor();

16 process.destroy();17 returnresult;18 } catch(IOException e) {19 e.printStackTrace();20 }21 return null;22 }

二、含有管道符(|)多级命令串联查询

public ListexecuteLinuxCmd(String cmd) {

System.out.println("got cmd job : " +cmd);

Runtime run=Runtime.getRuntime();try{//Process process = run.exec(cmd);

Process process = run.exec(new String[] {"/bin/sh", "-c", cmd});

InputStream in=process.getInputStream();

BufferedReader bs= new BufferedReader(newInputStreamReader(in));

List list = new ArrayList();

String result= null;while ((result = bs.readLine()) != null) {System.out.println("job result [" + result + "]");

list.add(result);

}

in.close();//process.waitFor();

process.destroy();returnlist;

}catch(IOException e) {

e.printStackTrace();

}return null;

}

三、含有cd操作的方法示例

1. 问题背景

1.1 java程序运行在/home/lings目录下；

1.2 希望删除/home/test目录下的文件proxy.log；

1.3 调用上面的接口两次？

executeLinuxCmd("cd /home/test");

executeLinuxCmd("rm -fr /home/proxy.log");

是不行的！

1.4 这个接口的调用是单次事务型的，就是每次调用都是独立的事务或者说操作，没有关联的。

那这种“复杂”一点的操作流程怎么办呢？

1.5 方法a: 可以写一个独立的脚本，然后一次运行脚本，这样多复杂的逻辑都没问题。

1.6 方法b: 可以启动一个shell长连接，保持连接，发送多条命令，最后释放连接。

示例逻辑代码：

1 public voidexecuteNewFlow() {2 Runtime run =Runtime.getRuntime();3 File wd = new File("/bin");4 System.out.println(wd);5 Process proc = null;6 try{7 proc = run.exec("/bin/bash", null, wd);8 } catch(IOException e) {9 e.printStackTrace();10 }11 if (proc != null) {12 BufferedReader in = new BufferedReader(newInputStreamReader(proc.getInputStream()));13 PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(proc.getOutputStream())), true);14 out.println("cd /home/test");15 out.println("pwd");16 out.println("rm -fr /home/proxy.log");17 out.println("exit");//这个命令必须执行，否则in流不结束。18 try{19 String line;20 while ((line = in.readLine()) != null) {21 System.out.println(line);22 }23 proc.waitFor();24 in.close();25 out.close();26 proc.destroy();27 } catch(Exception e) {28 e.printStackTrace();29 }30 }31 }

三的优化和演进(返回值)

public List executeNewFlow(Listcommands) {

List rspList = new ArrayList();

Runtime run=Runtime.getRuntime();try{

Process proc= run.exec("/bin/bash", null, null);

BufferedReaderin = new BufferedReader(newInputStreamReader(proc.getInputStream()));

PrintWriterout = new PrintWriter(new BufferedWriter(new OutputStreamWriter(proc.getOutputStream())), true);for(String line : commands) {out.println(line);

}//out.println("cd /home/test");//out.println("pwd");//out.println("rm -fr /home/proxy.log");

out.println("exit");//这个命令必须执行，否则in流不结束。

String rspLine = "";while ((rspLine = in.readLine()) != null) {

System.out.println(rspLine);

rspList.add(rspLine);

}

proc.waitFor();in.close();out.close();

proc.destroy();

}catch(IOException e1) {

e1.printStackTrace();

}catch(InterruptedException e) {

e.printStackTrace();

}returnrspList;

}