2020.11.13 first commit

exw8.java

@@ -0,0 +1,103 @@
+//第八周作业
+import java.util.Scanner;
+import java.io.*;
+import java.security.MessageDigest;
+//import java.util.Date;  //**
+
+public class exw8
+{
+	//SHA1计算哈希值
+	public static byte[] SHA1Checksum(InputStream instream) throws Exception
+	{
+		byte[] buffer = new byte[1024];
+		MessageDigest complete=MessageDigest.getInstance("SHA-1");
+		int numRead=0;
+		do{
+			numRead=instream.read(buffer);
+			if(numRead>0)
+			{
+				complete.update(buffer,0,numRead);
+			}
+			//文件已读完，退出循环
+		}while (numRead != -1);
+		//关闭输入流
+		instream.close();
+		//返回SHA1哈希值
+		return complete.digest();
+	}
+
+	//在存入fs列表前，对listFiles()方法取出来的东西进行排序，按照最后修改时间的由新到老*
+	public static File[] sortAfter_listFileMeth(File[] fs)
+	{
+		File temp;
+		for(int i=0 ; i<fs.length ; i++)
+		{
+			for(int j=0 ; j<fs.length ; j++)
+			{
+				if(fs[i].lastModified() > fs[j].lastModified())
+				{
+					temp=fs[i];
+					fs[i]=fs[j];
+					fs[j]=temp;
+				}
+			}
+		}
+		return fs;
+	}
+
+	//深度优先遍历文件夹
+	public static void dirDepthFirstTravel(String dirPath)
+	{
+		File dir=new File(dirPath);
+		File[] fs = sortAfter_listFileMeth(  dir.listFiles()  );  //使用了sortAfter_listFileMeth()排序
+		String result = "";
+		for(int i=0 ; i<fs.length ; i++)
+		{
+			//如果是文件
+			if(fs[i].isFile())
+			{
+				System.out.println("file-------"+fs[i].getName());
+
+				//文件哈希值计算区
+				//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+				try
+				{
+					FileInputStream instream= new FileInputStream(fs[i]);
+					byte[] sha1 = SHA1Checksum(instream);
+					for(int count=0 ; count < sha1.length ; count++)
+					{
+						result+= Integer.toString(sha1[count]&0xFF,16);
+					}
+				}catch (Exception e)
+				{
+					e.printStackTrace();
+				}
+				System.out.println("SHA1:"+result+"\r\n");
+				//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++				
+			}
+
+			//如果是子文件夹
+			if(fs[i].isDirectory())
+			{
+				System.out.println("directory--"+fs[i].getName()+"\r\n");
+				//递归，进入子文件夹继续遍历
+				dirDepthFirstTravel(dirPath+File.separator +fs[i].getName());
+			}
+		}
+	}
+
+    public static void main(String[] args) 
+	{
+		System.out.println("请输入文件夹路径");
+		Scanner instring=new Scanner(System.in);
+		String path = instring.next().toString();
+
+		try
+		{
+			dirDepthFirstTravel(path);
+		}catch (Exception e)
+		{
+			e.printStackTrace();
+		}
+    }
+}