java文件操作,java文件操作工具类

本文目录一览：

• 1、java 根据一个文件内容同时操作多个文件？
• 2、java里的文件操作
• 3、java遍历指定文件夹下的所有子文件夹怎么操作？
• 4、【高额奖赏】用java实现文件操作。
• 5、java 文件夹操作

java 根据一个文件内容同时操作多个文件？

可以用多线程来操作，java8的异步多线程CompletionStage接口，就可以实现，或者不使用多线程使用单线程版反应器模式Reactor（反应器）定制几个处理器接口，根据第一个文件的内容来分发到不同的处理器来处理你具体的需求，具体代码有空可以写给你

java里的文件操作

TextFileOutputDemo Part 1

public static void main(String[] args)

{

PrintWriter outputStream = null;

try

{

outputStream =

new PrintWriter(new FileOutputStream(“out.txt”));

}

catch(FileNotFoundException e)

{

System.out.println(“Error opening the file out.txt.”);

System.exit(0);

}

—————————————-

//: c11:IOStreamDemo.java

// Typical I/O stream configurations.

import java.io.*;

public class IOStreamDemo {

// Throw exceptions to console:

public static void main(String[] args)

throws IOException {

// 1. Reading input by lines:

BufferedReader in =

new BufferedReader(

new FileReader(“IOStreamDemo.java”));

String s, s2 = new String();

while((s = in.readLine())!= null)

s2 += s + “\n”;

in.close();

—————————————-

// 1b. Reading standard input:

BufferedReader stdin =

new BufferedReader(

new InputStreamReader(System.in));

System.out.print(“Enter a line:”);

System.out.println(stdin.readLine());

// 2. Input from memory

StringReader in2 = new StringReader(s2);

int c;

while((c = in2.read()) != -1)

System.out.print((char)c);

——————————————–

// 3. Formatted memory input

try {DataInputStream in3 =new DataInputStream(

new ByteArrayInputStream(s2.getBytes()));

while(true)

System.out.print((char)in3.readByte());

} catch(EOFException e) {

System.err.println(“End of stream”);

} // 4. File output

try { BufferedReader in4 =

new BufferedReader( new StringReader(s2));

PrintWriter out1 =

new PrintWriter(new BufferedWriter(

new FileWriter(“IODemo.out”)));

int lineCount = 1;

while((s = in4.readLine()) != null )

out1.println(lineCount++ + “: ” + s);

out1.close();

} catch(EOFException e) {

System.err.println(“End of stream”);

}

——————————————

// 5. Storing recovering data

try { DataOutputStream out2 =

new DataOutputStream(new BufferedOutputStream(

new FileOutputStream(“Data.txt”)));

out2.writeDouble(3.14159);

out2.writeChars(“That was pi\n”);

out2.writeBytes(“That was pi\n”); out2.close();

DataInputStream in5 = new DataInputStream(

new BufferedInputStream(

new FileInputStream(“Data.txt”)));

BufferedReader in5br =

new BufferedReader(new InputStreamReader(in5));

// Must use DataInputStream for data:

System.out.println(in5.readDouble());

// Can now use the “proper” readLine():

System.out.println(in5br.readLine());

System.out.println(in5br.readLine());

} catch(EOFException e) {

System.err.println(“End of stream”);}

————————————————-

// 6. Reading/writing random access files

RandomAccessFile rf =

new RandomAccessFile(“rtest.dat”, “rw”);

for(int i = 0; i 10; i++)

rf.writeDouble(i*1.414);

rf.close();

rf = new RandomAccessFile(“rtest.dat”, “rw”);

rf.seek(5*8);

rf.writeDouble(47.0001);

rf.close();

rf = new RandomAccessFile(“rtest.dat”, “r”);

for(int i = 0; i 10; i++)

System.out.println(

“Value ” + i + “: ” +

rf.readDouble());

rf.close();

}

}

————————————————–

//: c11:GZIPcompress.java

// Uses GZIP compression to compress a file

// whose name is passed on the command line.

import java.io.*;

import java.util.zip.*;

public class GZIPcompress {

// Throw exceptions to console:

public static void main(String[] args)

throws IOException {

BufferedReader in =

new BufferedReader(

new FileReader(args[0]));

BufferedOutputStream out =

new BufferedOutputStream(

new GZIPOutputStream(

new FileOutputStream(“test.gz”)));

System.out.println(“Writing file”);

int c;

while((c = in.read()) != -1)

out.write(c);

in.close();

out.close();

System.out.println(“Reading file”);

BufferedReader in2 =

new BufferedReader(

new InputStreamReader(

new GZIPInputStream(

new FileInputStream(“test.gz”))));

String s;

while((s = in2.readLine()) != null)

System.out.println(s);

}

}

java遍历指定文件夹下的所有子文件夹怎么操作？

import java.io.File ;\x0d\x0aimport java.io.IOException ;\x0d\x0apublic class FileDemo11{\x0d\x0apublic static void main(String args[]){\x0d\x0aFile my = new File(“d:” + File.separator) ;// 操作路径,可以有外部参数决定的\x0d\x0aprint(my) ;\x0d\x0a}\x0d\x0apublic static void print(File file){// 递归调用\x0d\x0aif(file!=null){// 判断对象是否为空\x0d\x0aif(file.isDirectory()){// 如果是目录\x0d\x0aFile f[] = file.listFiles() ;// 列出全部的文件\x0d\x0aif(f!=null){// 判断此目录能否列出\x0d\x0afor(int i=0;if.length;i++){\x0d\x0aprint(f[i]) ;// 因为给的路径有可能是目录，所以，继续判断\x0d\x0a}\x0d\x0a}\x0d\x0a}else{\x0d\x0aSystem.out.println(file) ;// 输出路径\x0d\x0a}\x0d\x0a}\x0d\x0a}\x0d\x0a};

【高额奖赏】用java实现文件操作。

1、执行代码如下，因不支持插入代码故放图片

2、执行结果

java 文件夹操作

你好，按照你的要求代码编写如下，可以直接运行

import java.io.File;

public class test {

public static void main(String[] args) {

File root = new File(“d:\\”);

for (File file : root.listFiles()) {

if (file.isDirectory()) {

for (File f : file.listFiles()) {

String fileName = f.getName();

if (fileName.endsWith(“.png”)) {

System.out.println(file.getName());

break;

}

}

}

}

}

}