文件操作入门_JAVA_编程开发_程序员俱乐部

class="MsoNormal" style="text-align: center; text-indent: 0.05pt; margin: 0cm 0cm 0pt;">文件操作入门

这段代码实现了最基础的文件操作：查，搜，读写和copy

我把这段代码传上来，以方便自己和他人的学习：

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package fileprogram;

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import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

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publicclass fileIO {

//检测是否存在：

?? publicvoid testFile(){

???? File file = new File("D:\\text.txt");

???? if(file.isDirectory()&&!file.exists()){

??????? //file.mkdir();这个只能创建一级目录

??????? file.mkdir();

??????? //可以创建多级目录

??????? file.mkdirs();

??????? try{

????????? //当且仅当不存在具有此抽象路径名指定名称的文件时，不可分地创建一个新的空文件。

????????? file.createNewFile();

??????? }catch? (IOException e){

????????? e.printStackTrace();

??????? }

???? }

???? //如果存在：更改文件名

???? if(file.isFile()){

??????? //打印该文件的绝对路径

??????? System.out.println(file.getAbsolutePath());

?? ??????? file.renameTo(new File("D:\\rename.txt"));

???? }

?? }

?? publicvoid find(File file,String findString){

???? //列出所有的子目录

???? File[] sonFiles = file.listFiles();

???? if(sonFiles != null){

??????? for(int i = 0;i<sonFiles.length;i++){

????????? File f = sonFiles[i];

????????? if(f.isFile()){

???????????? if(f.getName().indexOf(findString)!=-1){

?????????????? System.out.println(f.getAbsolutePath());

???????????? }else{

?????????????? find(f,findString);

???????????? }//else

????????? } //if

??????? }//for

???? }//if

????

?? }//

?? publicvoid readFile(){

???? try{

??????? FileInputStream fis = new FileInputStream("D:\\test.txt");

??????? System.out.println("fis.available()="+fis.available());

??????? //新建一个与文件大小相同的字节数组

??????? byte[] bytes = newbyte[fis.available()];

??????? //一次性把所有的数据都读到这个数组中

??????? fis.read(bytes);

??????? String content = new String(bytes,"GB2312");

??????? System.out.println(content);

??????? fis.close();

???? }catch(Exception e){

??????? e.printStackTrace();

???? }

?? }

?? //写入操作：

?? publicvoid writeFile(){

???? try{

??????? FileOutputStream fos = new FileOutputStream("D:\\text2.txt");

??????? String content = "Hello world";

??????? byte[] bytes = content.getBytes("gb2312");

??????? fos.write(bytes);

??????? fos.close();

???? }catch(Exception e){

??????? e.printStackTrace();

???? }?

?? }

?? //文件复制：

?? publicvoid copyFile(String src,String dest){

???? try {

??????? FileInputStream fiStream = new FileInputStream(src);

??????? FileOutputStream fos = new FileOutputStream(dest);

??????? int c = fiStream.read();

??????? while(c!=-1){

????????? c= c+12;//简单的加密代码

????????? fos.write(c);

????????? c = fiStream.read();

??????? }

??????? fiStream.close();//关闭

??????? fos.close();//关闭

???? }catch(Exception e){

??????? e.printStackTrace();

???? }

?? }

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?? publicstaticvoid main(String[] args) {

???? fileIO FileIO = new fileIO();

???? File file = new File("D:\\text.txt");

???? //FileIO.find(file, ".java");

???? //FileIO.testFile();

???? FileIO.copyFile("D:\\text.txt", "D:\\text2.txt");

?? }

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}

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