1.编写一个程序，指定一个文件夹，能自动计算出其总容量
package test;
import java.io.File;
import java.util.ArrayList;
public class test1 {
static long size=0;
private static ArrayList<String> filelist=new ArrayList<String>();
public static void main(String[] args) {
test1 s=new test1();
String filePath="D:\\abc";
s.getFiles(filePath);
}
void getFiles(String filePath) {
File root=new File(filePath);
File[] files=root.listFiles();
for(File file:files) {
if(file.isDirectory()) {
getFiles(file.getAbsolutePath());
filelist.add(file.getAbsolutePath());
}
else {
size+=file.getAbsolutePath().length();
}
}
System.out.println(size);
}
}
2.编写一个文件加解密程序，通过命令行完成加解密工作
package test;
import java.io.*;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class test2 {
public static void encryption() throws IOException {
BufferedInputStream sc = new BufferedInputStream(new FileInputStream("D:\\abc\\1.txt"));
BufferedOutputStream scan = new BufferedOutputStream(new FileOutputStream("D:\\abc\\2.txt"));
int b;
while((b = sc.read()) != -1) {
scan.write(b ^ 123);
}
sc.close();
scan.close();
}
public static void main(String[] args) throws IOException {
encryption();
}
}
3.编写一个文件分割工具，能把一个大文件分割成多个小的文件。并且能再次把它们合并起来得到完整的文件。
package test;
import java.io.*;
public class test3 {
public static void main(String args[])
{ try {
FileReader read = new FileReader("D:\\abc\\1.txt");
BufferedReader br = new BufferedReader(read);
String row;
int rownum = 1;
int fileNo = 1;
FileWriter fw = new FileWriter("D:/text"+fileNo +".txt");
while ((row = br.readLine()) != null) {
rownum ++; fw.append(row + "\r\n");
if((rownum / 464183) > (fileNo - 1)){
fw.close(); fileNo ++ ;
fw = new FileWriter("D:/text"+fileNo +".txt");
}
}
fw.close();
System.out.println("rownum="+rownum+";fileNo="+fileNo);
} catch (FileNotFoundException e) {
e.printStackTrace(); } catch (IOException e)
{ e.printStackTrace();
}
}
}
原文：https://www.cnblogs.com/zlj843767688/p/9986730.html