Java:如何检查2个二进制文件是否相同？

Question

检查(在单元测试中)二进制文件A和B是否相等的最简单方法是什么？

Answer 1

第三方图书馆是公平游戏吗？番石榴有Files.equal(File, File).如果你不需要,没有真正的理由去打扰哈希; 它只会效率低下.

Answer 2

总是只是从每个文件中逐字节读取并随时比较它们.Md5和Sha1等仍然必须读取所有字节,因此计算哈希是额外的工作,你不必这样做.

if(file1.length() != file2.length()){
        return false;
 }

 try(   InputStream in1 =new BufferedInputStream(new FileInputStream(file1));
    InputStream in2 =new BufferedInputStream(new FileInputStream(file2));
 ){

      int value1,value2;
      do{
           //since we're buffered read() isn't expensive
           value1 = in1.read();
           value2 = in2.read();
           if(value1 !=value2){
           return false;
           }
      }while(value1 >=0);

 //since we already checked that the file sizes are equal 
 //if we're here we reached the end of both files without a mismatch
 return true;
}