java代码实现对文件的base64加密解密

Base64编码方法:将每三个8bit的字节转换为四个6bit的字节,其中,转换之后的这四个字节中每6个有效Bbit为有效数据,空余的那2个用0补上成为一个字节,java中可直接调用算法进行base64加密解密。

public class base64 {

    public static void main(String[] args){
        File file = new File("D:\\base64.txt");
        String result = getFromBase64(file2String(file));
        System.out.println(result);
    }

    //文件转字符串
    public static String file2String(File file){
        try {
            BufferedReader buffer = new BufferedReader(new FileReader(file));
            StringBuilder sb = new StringBuilder();
            String temp;
            while((temp = buffer.readLine()) !=null ){
                sb.append(temp);

            }
            return sb.toString();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;
        }
    }
    //加密
    public static String getBase64(String str){
        byte[]  b = null;
        String s = null;
        try {
            b = str.getBytes("utf-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        if( b != null){
             s = new BASE64Encoder().encode(b);
        }
        return s;

    }

    //解密
    public static String getFromBase64(String str){
        byte[] b = null;
        String result = null;
        if(str != null){
             BASE64Decoder decoder = new BASE64Decoder();  
             try {  
                    b = decoder.decodeBuffer(str);  
                    result = new String(b, "utf-8");  
                } catch (Exception e) {  
                    e.printStackTrace();  
                }  
        }
        return result;
    }

}

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