判断两个文件内容是否相同

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package cn.bl.file;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * 判断两个文件是否内容完全相同
 * @author BarryLee
 * @2018年11月1日@下午10:16:50
 */
public class FileEquals {
	public static void main(String[] args) {
		File file1 = new File("E:/a/a.txt");
		File file2 = new File("E:/a/a - 副本.txt");
		String str1 = getMD5Str(file1);
		String str2 = getMD5Str(file2);
		System.out.println(str1.equals(str2));
	}
	public static String getMD5Str(File file) {
		if(!file.isFile()) {
			System.out.println(file.getName()+"不是文件");
			return null;
		}
		InputStream in = null;
		try {
			MessageDigest digest = MessageDigest.getInstance("MD5");
			in = new FileInputStream(file);
			byte[]bs = new byte[1024];
			int len = -1;
			while((len=in.read(bs))!=-1) {
				digest.update(bs,0,len);
			}
			BigInteger bi = new BigInteger(1,digest.digest());
			return bi.toString(16);
		} catch (NoSuchAlgorithmException e) {
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				in.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return null;
	}
}