[Java] 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;
  }
 
}