有些时候会碰到这样的场景：java的功能里面要嵌入一个功能点，这个功能是通过是shell脚本实现的。这种时候就需要Java对脚本调用的支持了。
测试环境
Ubuntu16.04 i3-6100,12GB
Hello World
来看一个基本的例子
Process exec = Runtime.getRuntime().exec(new String[] { "uname" ,"-a"});
exec.waitFor();
BufferedReader reader =
new BufferedReader(new InputStreamReader(exec.getInputStream()));
System.out.println(reader.readLine());
Linux jason-Inspiron-3650 4.4.0-121-generic #145-Ubuntu SMP Fri Apr 13 13:47:23 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux解读Process
java.lang.Process类提供了获取输入、输出、等待执行和销毁进程的方法。
Process类可通过ProcessBuilder.start() 和 Runtime.exec 创建实例，从Java1.5开始，ProcessBuilder.start()是更推荐的做法，但网上的教程更多推荐用Runtime.exec()方法。
| Modifier and Type | Method | Description |
|---|---|---|
| abstract void | destroy () | Kills the subprocess. |
| abstract int | exitValue () | Returns the exit value for the subprocess. |
| abstract InputStream | getErrorStream () | Returns the input stream connected to the error output of the subprocess. |
| abstract InputStream | getInputStream () | Returns the input stream connected to the normal output of the subprocess. |
| abstract OutputStream | getOutputStream () | Returns the output stream connected to the normal input of the subprocess. |
| abstract int | waitFor () | Causes the current thread to wait, if necessary, until the process represented by this Process object has terminated. |
继承体系上面，Process的实现类是JDK内置的，linux版本的jdk中只带有一个实现类UnixProcess。
与脚本交互
Process不但可以执行进程，还可以获取进程的返回结果。
private String executeCommand(String command) {
StringBuffer output = new StringBuffer();
Process p;
try {
p = Runtime.getRuntime().exec(command);
int exitCode = p.waitFor();
System.out.println(exitCode);
BufferedReader reader =
new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = "";
while ((line = reader.readLine()) != null) {
output.append(line + "\n");
}
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(output.toString());
return output.toString();
}
PING www.a.shifen.com (111.13.100.91) 56(84) bytes of data.
64 bytes from localhost (111.13.100.91): icmp_seq=1 ttl=52 time=7.66 ms
64 bytes from localhost (111.13.100.91): icmp_seq=2 ttl=52 time=7.90 ms
64 bytes from localhost (111.13.100.91): icmp_seq=3 ttl=52 time=14.0 ms
--- www.a.shifen.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 7.668/9.861/14.013/2.937 ms总结
Java 执行脚本的方式其实类似用直接在bash里面执行脚本，区别在于环境有些变动，执行的效果和bash基本一致。
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