ios图片上传翻转问题解决

开发微信服务，有个上传头像的功能，前端用html5的方法来上传头像
<img id="babyHead"src="$session.getAttribute('picUrl')"style="width:74px;height:74px;border-radius:37px;"/>
<label class="camera"><i class="fa fa-camera"aria-hidden="true"></i>
<input id="f1"name="f1"class="weui_uploader_input"type="file"capture="camera"accept="image/*"multiple="">
                       
.on("change", "#f1", function(){
        $("#loadingToast").show()
        var fileName = $(this).val();
        if (fileName.length > -1) {
        jQuery.ajaxFileUpload({
    url:jQuery("#confirmUrl").val(),
    type: 'post',
    secureuri:false,
    fileElementId:'f1',
    data:{
    type:'5'},
    dataType:"json",
    success: function(data, status){
    $('#babyHead').attr('src',data.url);
  $('#headUrl').val(data.url);
  $("#loadingToast").hide();
              },error:function(data,status,e){
  alert(e);
  }
  });
        } else {
            alert("请选择图片上传！");
        }
    });
上传到后端的头像竟然会出现各种翻转，基本就是90度的倍数。
查找后得知是ios的拍照片时记录了拍摄的翻转角度。为了把这个角度纠正过来，在java中需要调用metadata-extractor
maven引用如下
<dependency><groupId>com.drewnoakes</groupId><artifactId>metadata-extractor</artifactId><version>2.9.1</version></dependency>
网上很多引用2.3.1的做法，实际上已经不能用了，在2.9.1中原先老的ExifDirector变成了n个directory，我通过for循环挨个试出来，当ExifDirector为ExifIFD0Directory时，才可以调用ExifDirectoryBase.TAG_ORIENTATION来判断翻转的角度，具体方法如下面的代码，我的思路是得到翻转的数值：6,3,8来得到需要右转的角度：90,180,270，然后调用Graphics2D的rotate方法来翻转
1.得到角度
privateintgetRotateAngleForPhoto(String filePath){
        int angle = 0;
        File imgFile = new File(filePath);
        try {
            Metadata metadata = ImageMetadataReader.readMetadata(imgFile);
            for (Directory directory : metadata.getDirectories()) {
                if ("ExifIFD0Directory".equalsIgnoreCase(directory.getClass()
                        .getSimpleName())) {
                    if (directory
                            .containsTag(ExifDirectoryBase.TAG_ORIENTATION)) {
                        // Exif信息中方向　　int orientation = directory
                                .getInt(ExifDirectoryBase.TAG_ORIENTATION);
                        logger.info("orientation=" + orientation);
                        switch (orientation) {
                        case6:
                            angle = 90;
                            break;
                        case3:
                            angle = 180;
                            break;
                        case8:
                            angle = 270;
                            break;
                        default:
                            return 0;
                        }

                    }
                }

            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return angle;
    }
2.调用的翻转方法
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.imageio.ImageIO;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
     * 向右旋转angle角度
     * @param img
     * @param angle
     * @return
     */
    public static void rotate(File image, int angle,String targetFolderPath,String targetFileName) throws IOException {
        BufferedImage img = ImageIO.read(image);
        int w = img.getWidth();
        int h = img.getHeight();
        BufferedImage dimg = new BufferedImage(w, h, img.getType());
        Graphics2D g = dimg.createGraphics();
        g.rotate(Math.toRadians(angle), w / 2, h / 2);
        g.drawImage(img, null, 0, 0);
        commonIoWrite(targetFolderPath, targetFileName, dimg, g);
    }

3.根据翻转的角度来调用对应的rotate方法
intangle = getRotateAngleForPhoto(sourcePath);
if (getRotateAngleForPhoto(sourcePath) > 0) {
    ImageUtil.rotate(new File(smallPath),angle, path, smallFileName);
}
其中smallPath是源文件地址，angle是向右翻转角度，path是目标文件夹，smallFileName是最终的文件名