java使用Base64实现文件加密解密

package test.base64;

import java.io.fileinputstream;

import java.io.fileoutputstream;

import java.io.ioexception;

import java.io.inputstream;

import java.io.outputstream;

import sun.misc.base64decoder;

import sun.misc.base64encoder;

/**

* 服务器之间传递图片

*/

public class testcase {

public static void main(string[] args) {

// 将图片文件转化为字节数组字符串，并对其进行base64编码处理

string strimg = getimagestr();

system.out.println(strimg);

// 对字节数组字符串进行base64解码并生成图片

generateimage(strimg);

}

public static string getimagestr() {

string imgfile = "d:\\java.pdf" ; // 待处理的图片

inputstream in = null ;

byte [] data = null ;

// 读取图片字节数组

try {

in = new fileinputstream(imgfile);

data = new byte [in.available()];

in.read(data);

in.close();

} catch (ioexception e) {

e.printstacktrace();

}

// 对字节数组base64编码

base64encoder encoder = new base64encoder();

return encoder.encode(data); // 返回base64编码过的字节数组字符串

}

public static boolean generateimage(string imgstr) {

if (imgstr == null ){ // 图像数据为空

return false ;

}

base64decoder decoder = new base64decoder();

try {

// base64解码

byte [] b = decoder.decodebuffer(imgstr);

for ( int i = 0 ; i < b.length; ++i) {

if (b[i] < 0 ) { // 调整异常数据

b[i] += 256 ;

}

}

// 生成jpg图片

string imgfilepath = "d:\\new.pdf" ; // 新生成的图片

outputstream out = new fileoutputstream(imgfilepath);

out.write(b);

out.flush();

out.close();

return true ;

} catch (exception e) {

return false ;

}

}

}

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;

   }

}