mac系统安装chromedriver请参考：
[WebDriver]Mac安装chromedriver

Windows系统安装chromedriver：

1.从http://chromedriver.storage.googleapis.com/index.html下载chromedriver包，注意chromedriver和chrome浏览器的版本对应关系。

2.将chromedriver解压放到chrome的安装目录下

3.设置环境变量
选择系统变量Path，点击编辑：

将chromedriver的目录设置到Path中：

设置完环境变量，命令chromedriver -v验证下是否设置成功，如果设置成功，回显中会显示版本信息：

4.写个demo代码吧：

public static void main(String[] args) {
        ChromeDriver client = null;
        try {
            ChromeOptions options = new ChromeOptions();
            options.addArguments("--headless");
            options.addArguments("--disable-gpu");

            client = new ChromeDriver (options);
            client.manage().deleteAllCookies();
            client.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
            Dimension dimension = new Dimension(1400, 900);
            client.manage().window().setSize(dimension);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
}

执行会报错：
The path to the driver executable must be set by the webdriver.chrome.driver system property; for more information, see https://github.com/SeleniumHQ/selenium/wiki/ChromeDriver. The latest version can be downloaded from http://chromedriver.storage.googleapis.com/index.html

需要在new ChromeDriver()前加段代码，设置webdriver.chrome.driver系统变量，这样就可以成功启动ChromeDriver实例了。

public static void main(String[] args) {
        ChromeDriver client = null;
        // 设置系统变量：
        System.setProperty("webdriver.chrome.driver","C:\\Program Files (x86)\\Google\\Chrome\\Application\\chromedriver.exe");
        try {
            ChromeOptions options = new ChromeOptions();
            options.addArguments("--headless");
            options.addArguments("--disable-gpu");

            client = new ChromeDriver (options);
            client.manage().deleteAllCookies();
            client.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
            Dimension dimension = new Dimension(1400, 900);
            client.manage().window().setSize(dimension);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
}