区分上传照片是否原类型图片上传

package com.csf.study;

 

import java.util.HashMap;

 

public class FileTypeUtils {

 

public static final String IMAGE_JPEG = "image/jpeg";

public static final String IMAGE_PNG = "image/png";

public static final String IMAGE_GIF = "image/gif";

public static final String IMAGE_BMP = "image/bmp";

 

 

private static final HashMap<String, String> mFileTypes = new HashMap<String, String>();

static {

mFileTypes.put("FFD8FF", IMAGE_JPEG);

mFileTypes.put("89504E47", IMAGE_PNG);

mFileTypes.put("47494638", IMAGE_GIF);

mFileTypes.put("424D", IMAGE_BMP);

mFileTypes.put("25504446", "application/pdf");

}

 

/**

* 获取图片格式

*/

    public static String getImgContentType(byte[] src) {

StringBuilder builder = new StringBuilder();

if (src == null || src.length <= 0) {

return null;

}

String contentType;

String hv;

for (int i = 0; i < 4 && i < src.length; i++) {

// 以十六进制（基数 16）无符号整数形式返回一个整数参数的字符串表示形式，并转换为大写

hv = Integer.toHexString(src[i] & 0xFF).toUpperCase();

if (hv.length() < 2) {

builder.append(0);

}

builder.append(hv);

contentType = mFileTypes.get(builder.toString());

if(contentType!=null){

return contentType;

}

}

contentType = "image/jpeg";

return contentType;

}

 

}