JAVA对文件类型的校验

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 第一步：编写一个枚举，在网上可以找到一些文件后缀所对应的前6位编码，例如JPEG对应的是FFD8FF

 

package com.ssh.pm_mark.core.test;

public 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"),  
		      
		    /** 
		     * Rich Text Format. 
		     */  
		    RTF("7B5C727466"),  
		      
		    /** 
		     * XML. 
		     */  
		    XML("3C3F786D6C"),  
		      
		    /** 
		     * HTML. 
		     */  
		    HTML("68746D6C3E"),  
		      
		    /** 
		     * Email [thorough only]. 
		     */  
		    EML("44656C69766572792D646174653A"),  
		      
		    /** 
		     * Outlook Express. 
		     */  
		    DBX("CFAD12FEC5FD746F"),  
		      
		    /** 
		     * Outlook (pst). 
		     */  
		    PST("2142444E"),  
		      
		    /** 
		     * MS Word/Excel. 
		     */  
		    XLS_DOC("D0CF11E0"),  
		      
		    /** 
		     * MS Access. 
		     */  
		    MDB("5374616E64617264204A"),  
		      
		    /** 
		     * WordPerfect. 
		     */  
		    WPD("FF575043"),  
		      
		    /** 
		     * Postscript. 
		     */  
		    EPS("252150532D41646F6265"),  
		      
		    /** 
		     * Adobe Acrobat. 
		     */  
		    PDF("255044462D312E"),  
		      
		    /** 
		     * Quicken. 
		     */  
		    QDF("AC9EBD8F"),  
		     
		   /** 
	  * Windows Password. 
		
		     */  
		  PWL("E3828596"),  
		      
		    /** 
	     * ZIP Archive. 
		     */  
	    ZIP("504B0304"),  
		      
	           /** 
		     * RAR Archive. 
		   */  
		   RAR("52617221"),  
		     
		   /** 
		    * Wave. 
		     */  
		  WAV("57415645"),  
		     
		   /** 
		     * AVI. 
		    */  
		   AVI("41564920"),  
		  
		 /** 
		   * Real Audio. 
		  */  
		   RAM("2E7261FD"),  
		     
		   /** 
		   * Real Media. 
		  */  
		   RM("2E524D46"),  
		    
		    /** 
		     * MPEG (mpg). 
		    */  
		  MPG("000001BA"),  
		    
		   /** 
		     * Quicktime. 
		     */  
		    MOV("6D6F6F76"),  
		      
		    /** 
		     * Windows Media. 
		    */  
		   ASF("3026B2758E66CF11"),  
		      
	  /** 
		     * MIDI. 
		  */  
		   MID("4D546864");  
		     
		   private String value = "";  
		     
		   /** 
	     * Constructor. 
		  *  
		    * @param type  
		    */  
		    private FileType(String value) {  
		        this.value = value;  
	  }  
	  
		    public String getValue() {  
		       return value;  
		    }  
		  
		    public void setValue(String value) {  
		        this.value = value;  
		   }  
		} 

 

第二步就是编写java类

 

package com.ssh.pm_mark.core.test;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

public class FileTypeJudge {
	    private FileTypeJudge() {}  
	      
	    /** 
	     * 将文件头转换成16进制字符串 
	     *  
	     * @param 原生byte 
	     * @return 16进制字符串 
	     */  
	    private static String bytesToHexString(byte[] src){  
	          
	        StringBuilder stringBuilder = new StringBuilder();     
	        if (src == null || src.length <= 0) {     
	            return null;     
	        }     
	        for (int i = 0; i < src.length; i++) {     
	            int v = src[i] & 0xFF;     
	            String hv = Integer.toHexString(v);     
	            if (hv.length() < 2) {     
	                stringBuilder.append(0);     
	            }     
	            stringBuilder.append(hv);     
	        }     
	        return stringBuilder.toString();     
	    }  
	     
	    /** 
	     * 得到文件头 
	     *  
	     * @param filePath 文件路径 
	     * @return 文件头 
	     * @throws IOException 
	     */  
	    private static String getFileContent(String filePath) throws IOException {  
	          
	        byte[] b = new byte[28];  
	          
	        InputStream inputStream = null;  
	          
	        try {  
	            inputStream = new FileInputStream(filePath);  
	            inputStream.read(b, 0, 28);  
	        } catch (IOException e) {  
	            e.printStackTrace();  
	            throw e;  
	        } finally {  
	            if (inputStream != null) {  
	                try {  
	                    inputStream.close();  
	                } catch (IOException e) {  
	                    e.printStackTrace();  
	                    throw e;  
	                }  
	            }  
	       }  
	        return bytesToHexString(b);  
	    }  
	      
	    /** 
	     * 判断文件类型 
	     *  
	     * @param filePath 文件路径 
	     * @return 文件类型 
	     */  
	    public static FileType getType(String filePath) throws IOException {  
	          
	        String fileHead = getFileContent(filePath);  
	          
	        if (fileHead == null || fileHead.length() == 0) {  
	            return null;  
	        }  
	          
	        fileHead = fileHead.toUpperCase();  
	          
	        FileType[] fileTypes = FileType.values();  
	          
	        for (FileType type : fileTypes) {  
	            if (fileHead.startsWith(type.getValue())) {  
	                return type;  
	            }  
	        }  
	          
	        return null;  
	   }  
	    
	    public static void main(String args[]) throws Exception {  
	    	       System.out.println(FileTypeJudge.getType("C:\\Users\\Administrator\\Desktop\\新建文本文档.t"));  
	    	    } 


}