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：public String executeLinuxCmd(String cmd) {

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

Runtime run = Runtime.getRuntime();

try {

Process process = run.exec(cmd);

InputStream in = process.getInputStream();

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

// 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() + "]");

in.close();

// process.waitFor();

process.destroy();

return result;

} catch (IOException e) {

e.printStackTrace();

}

return null;

}

二、含有管道符(|)多级命令串联查询public List 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 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();

return list;

} catch (IOException e) {

e.printStackTrace();

}

return null;

}

三、含有cd操作的方法示例问题背景

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：public void executeNewFlow() {

Runtime run = Runtime.getRuntime();

File wd = new File("/bin");

System.out.println(wd);

Process proc = null;

try {

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

} catch (IOException e) {

e.printStackTrace();

}

if (proc != null) {

BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream()));

PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(proc.getOutputStream())), true);

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。

try {

String line;

while ((line = in.readLine()) != null) {

System.out.println(line);

}

proc.waitFor();

in.close();

out.close();

proc.destroy();

} catch (Exception e) {

e.printStackTrace();

}

}

}

三的优化和演进(返回值)public List executeNewFlow(List commands) {

List rspList = new ArrayList();

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;

}