以16进制的方式判断文件上传的类型

我就是我 2022-06-02 04:59 121阅读 0赞

import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    
    public class FileTypeUtil {
    
        private FileTypeUtil() {
        }
    
        /** * 把文件头转换成16进制 * @param src * @return */ private static String bytesToHexString(byte[] src) {
            StringBuilder sb = new StringBuilder();
            if (src == null || src.length < 0) {
                return null;
            }
            for (int i = 0; i < src.length; i++) {
                int h = src[i] & 0xFF;
                String hv = Integer.toHexString(h);
                if (hv.length() < 2) {
                    sb.append(0);
                }
                sb.append(hv);
            }
            return sb.toString().toUpperCase();
        }
    
        private static String getFileContent(String filePath) {
            byte[] bytes = new byte[28];
            File file = new File(filePath);
            if(!file.exists()){
                return null;
            }
            FileInputStream fileInputStream;
            try {
                fileInputStream = new FileInputStream(file);
                fileInputStream.read(bytes, 0, 28);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
    
            return bytesToHexString(bytes);
        }
    
        public static FileType getFileType(String filePath) {
            if (filePath == null || filePath == "") {
                return null;
            }
            String fileContent = getFileContent(filePath);
            if (fileContent == null || fileContent == "") {
                return null;
            }
            FileType[] fileTypes = FileType.values();
            for (FileType fileType : fileTypes) {
                if (fileContent.startsWith(fileType.getValue())) {
                    return fileType;
                }
            }
            return null;
        }
    
        public static void main(String[] args) {
            String s = getFileType("E:\\QP\\7a76a296b072ebe17507bd31709e9dc4.png").name().toLowerCase();
            if (s != null && s != "") {
                System.out.println(s);
            }
        }
    
        public static enum FileType {
            /** * JEPG. */ JPEG("FFD8FF"),
    
            /** * PNG. */ PNG("89504E47"),
    
            /** * GIF. */ GIF("47494638"),
    
            /** * TIFF. */ TIFF("49492A00"),
    
            /** * Windows Bitmap. */ BMP("424D"),
    
            /** * CAD. */ DWG("41433130"),
    
            /** * Adobe Photoshop. */ PSD("38425053"),
            /** * MS Word/Excel. */ XLS_DOC("D0CF11E0"),
    
            XLSX_DOCX("504B0304"),
    
            /** * Rich Text Format. */ RTF("7B5C727466");
    
            private String value;
    
            private FileType(String value) {
                this.value = value;
            }
    
            public String getValue() {
                return value;
            }
    
            public void setValue(String value) {
                this.value = value;
            }
        }
    }