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 public String 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 \n"+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 return result; 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 List<String> executeLinuxCmd(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(new InputStreamReader(in)); List<String> list = new ArrayList<String>(); String result = null; while ((result = bs.readLine()) != null) { System.out.println("job result [" + result + "]"); list.add(result); } in.close(); // process.waitFor(); process.destroy(); return list; } 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 void executeNewFlow() { 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(new InputStreamReader(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<String> executeNewFlow(List<String> commands) { List<String> rspList = new ArrayList<String>(); Runtime run = Runtime.getRuntime(); try { Process proc = run.exec("/bin/bash", null, null); BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream())); PrintWriter out = 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(); } return rspList; }标签:Java,cmd,cd,Linux,println,new,null,proc,out From: https://www.cnblogs.com/kn-zheng/p/17024776.html