java: 多进程简易操作

java用了这么久，貌似没有使用过多进程。貌似一般的需求里面也不涉及这个方面。

但是，有时候确实有这种奇怪的需求，比如xxx.

于是，通过翻阅api文档，以及参考往上博客，写了一个简单的多进程程序。

package com.pythoncat.java.process;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Arrays;

/**
 * Created on 2017/8/11.
 * from http://www.jianshu.com/p/428bbc3852a7
 * @author cat
 */
public class NewlyProcess {
    public static void main(String[] args) throws IOException, InterruptedException {

        createProcess("java", "-version");

//        CmdToolkit.readConsole("java",true);
        createProcess("git","status");
    }

    private static void createProcess(String... cmd) throws IOException, InterruptedException {
//        ProcessBuilder pb = new ProcessBuilder("java", "-version");
        ProcessBuilder pb = new ProcessBuilder(cmd);
        pb.redirectErrorStream(true);
        Process process = pb.start();
        process.waitFor();

        InputStream in = process.getInputStream();
        BufferedReader br = new BufferedReader(new InputStreamReader(in));

        String line;
        StringBuilder sb = new StringBuilder();
        sb.append("---------------------------------\n");
        sb.append("commands:\t")
                .append(Arrays.toString(cmd))
                .append("\n");
//        System.out.println(sb);
        sb.append("RESULT:\t").append("\n");
        while ((line = br.readLine()) != null) {
            sb.append(line).append("\n");
        }
        sb.append("---------------------------------\n");

        System.out.println(sb.toString());
    }
}

代码量很少，主要的代码还是用于打印输出了。输出结果如下：

---------------------------------
commands:   [java, -version]
RESULT: 
java version "1.8.0_131"
Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)
---------------------------------

---------------------------------
commands:   [git, status]
RESULT: 
fatal: Not a git repository (or any of the parent directories): .git
---------------------------------

其中关键逻辑至于3行

ProcessBuilder pb = new ProcessBuilder(cmd);
pb.redirectErrorStream(true);
Process process = pb.start();
process.waitFor();