Java PhantomJs完成html图片输出功能

# 1. 下载
## mac 系统
wget https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-2.1.1-macosx.zip
## linux 系统
wget https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-2.1.1-linux-x86_64.tar.bz2
## windows 系统
## 就不要玩了，没啥意思
# 2. 解压
sudo su 
tar -jxvf phantomjs-2.1.1-linux-x86_64.tar.bz2
# 如果解压报错，则安装下面的
# yum -y install bzip2
# 3. 安装
## 简单点，移动到bin目录下
cp phantomjs-2.1.1-linux-x86_64/bin/phantomjs /usr/local/bin
# 4. 验证是否ok
phantomjs --version
# 输出版本号，则表示ok

<!--phantomjs -->
<dependency>
  <groupId>org.seleniumhq.selenium</groupId>
  <artifactId>selenium-java</artifactId>
  <version>2.53.1</version>
</dependency>
<dependency>
  <groupId>com.github.detro</groupId>
  <artifactId>ghostdriver</artifactId>
  <version>2.1.0</version>
</dependency>
<repositories>
  <repository>
    <id>jitpack.io</id>
    <url>https://jitpack.io</url>
  </repository>
</repositories>

public class Html2ImageByJsWrapper {
  private static PhantomJSDriver webDriver = getPhantomJs();
  private static PhantomJSDriver getPhantomJs() {
    //设置必要参数
    DesiredCapabilities dcaps = new DesiredCapabilities();
    //ssl证书支持
    dcaps.setCapability("acceptSslCerts", true);
    //截屏支持
    dcaps.setCapability("takesScreenshot", true);
    //css搜索支持
    dcaps.setCapability("cssSelectorsEnabled", true);
    //js支持
    dcaps.setJavascriptEnabled(true);
    //驱动支持（第二参数表明的是你的phantomjs引擎所在的路径，which/whereis phantomjs可以查看）
    // fixme 这里写了执行， 可以考虑判断系统是否有安装，并获取对应的路径 or 开放出来指定路径
    dcaps.setCapability(PhantomJSDriverService.PHANTOMJS_EXECUTABLE_PATH_PROPERTY, "/usr/local/bin/phantomjs");
    //创建无界面浏览器对象
    return new PhantomJSDriver(dcaps);
  }
  public static BufferedImage renderHtml2Image(String url) throws IOException {
    webDriver.get(url);
    File file = webDriver.getScreenshotAs(OutputType.FILE);
    return ImageIO.read(file);
  }
}

public class Base64Util {
  public static String encode(BufferedImage bufferedImage, String imgType) throws IOException {
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    ImageIO.write(bufferedImage, imgType, outputStream);
    return encode(outputStream);
  }
  public static String encode(ByteArrayOutputStream outputStream) {
    return Base64.getEncoder().encodeToString(outputStream.toByteArray());
  }
}
@Test
public void testRender() throws IOException {
  BufferedImage img = null;
  for (int i = 0; i < 20; ++i) {
    String url = "https://my.oschina.net/u/566591/blog/1580020";
    long start = System.currentTimeMillis();
    img = Html2ImageByJsWrapper.renderHtml2Image(url);
    long end = System.currentTimeMillis();
    System.out.println("cost: " + (end - start));
  }
  System.out.println(Base64Util.encode(img, "png"));
}