【Java】如何调用系统命令

如何通过Java调用系统命令，如ping 127.0.0.1、java -version等？

> 简单的例子

package com.nicchagil.callpython.No001无参数调用;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class HowToCallSystemCommand {

    public static void main(String[] args)  {
        BufferedReader in = null;
        try {
            /* 调用、输出 */
            Process process = Runtime.getRuntime().exec("ping 127.0.0.1");
            in = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line = null;
            while ((line = in.readLine()) != null) {
                System.out.println(line);
            }
            
            /* 判断是否正常 */
            int waitFor = process.waitFor();
            System.out.println("waitFor -> " + waitFor);
            if (process.waitFor() == 0) {
                System.out.println("Normal termination.");
            } else {
                System.out.println("Abnormal termination.");
            }
        } catch (Exception e) {
            // TODO
            e.printStackTrace();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    // TODO
                    e.printStackTrace();
                }
            }
            System.out.println("Done...");
        }
    }

}

执行后，发现对于“ping 127.0.0.1”能完整的打印出日志，而对于“java -version”却无日志输出，原因在于它们输出的级别不同。

于是，作了下简单修改。

package com.nicchagil.callpython.No001无参数调用;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class HowToCallSystemCommand {

    public static void main(String[] args)  {
        BufferedReader inputBufferedReader = null;
        BufferedReader errorBufferedReader = null;
        try {
            /* 调用、输出 */
            Process process = Runtime.getRuntime().exec("java -version");
            inputBufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            errorBufferedReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
            String line = null;
            
            System.out.println("Input Stream -> ");
            while ((line = inputBufferedReader.readLine()) != null) {
                System.out.println(line);
            }
            
            System.out.println("Error Stream -> ");
            while ((line = errorBufferedReader.readLine()) != null) {
                System.out.println(line);
            }
            
            /* 判断是否正常 */
            int waitFor = process.waitFor();
            System.out.println("waitFor -> " + waitFor);
            if (process.waitFor() == 0) {
                System.out.println("Normal termination.");
            } else {
                System.out.println("Abnormal termination.");
            }
        } catch (Exception e) {
            // TODO
            e.printStackTrace();
        } finally {
            if (inputBufferedReader != null) {
                try {
                    inputBufferedReader.close();
                } catch (IOException e) {
                    // TODO
                    e.printStackTrace();
                }
            }
            System.out.println("Done...");
        }
    }

}

分别执行两个命令，查询日志，发现OK了，哈哈哈。