检测某一目录下md5相同的文件

import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.io.IOUtils;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * 检测某一目录下md5相同的文件
 */
public class Test {

    public static void main(String[] args) throws IOException {
        Map<String, String> map = new HashMap<String, String>();
        Map<String, List<String>> map1 = new HashMap<String, List<String>>();
        String path = "D:\\Nihaorz\\Documents\\work\\综合运维基线包\\实时解压版本\\OperationCenter-1.8\\OperationCenter\\WEB-INF\\lib";
        File dir = new File(path);
        File[] files = dir.listFiles();
        for (File file : files) {
            String fileName = file.getName();
            String md5 = DigestUtils.md5Hex(IOUtils.toByteArray(new FileInputStream(file)));
            if (!map.containsKey(md5)) {
                map.put(md5, fileName);
            } else {
                if (!map1.containsKey(md5)) {
                    List<String> list = new ArrayList<String>();
                    list.add(fileName);
                    map1.put(md5, list);
                } else {
                    map1.get(md5).add(fileName);
                }
            }
        }
        if (map1.size() > 0) {
            System.out.println("有如下jar包md5码重复");
            System.out.println("------------------------------------------");
            Iterator<String> it = map1.keySet().iterator();
            while (it.hasNext()) {
                String md5 = it.next();
                System.out.println("MD5:" + md5);
                System.out.println("fileName:" + map.get(md5));
                List<String> fileNames = map1.get(md5);
                for (String fileName : fileNames) {
                    System.out.println("fileName:" + fileName);
                }
            }
        }
    }

}